Pagoda SL Group
W113 Pagoda SL Group => Drive train, fuel, suspension, steering & brakes => Topic started by: mrfatboy on February 02, 2012, 00:41:00
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Hey Guys,
I was hoping somebody could help me out with my CO numbers for my 69 280sl stick. I have borrowed a Gunson CO meter and come up with the following information.
650rpm Idle w/vac (I can't seem to get it higher) is 3.5% - 4.5%. Within spec from the manual.
1500 rpm is 11%-12% (should be 1.5 -3.0) From the manual
3000 rpm is 11%-12% (should be 0.2 -1.5) From the manual
The manual states that the 1500 & 3000 rpm should be under partial load. I don't have a dyno so this is all done parked in the driveway :(
What should I be able to gleen from the 1500 & 3000rpm CO readings if anything while just sitting in the driveway doing these tests? Can I use the numbers to make my CO adjustments. If so, I assume I could lean out the 1500 & 3000rpm ranges by removing shims in the WRD or BC and then increase richness at idle using the knob on the back of the pump. I have an adjustable bolt in the FIP where the BC goes to adjust the fuel mixture across all ranges.
Is the doable? Can I even look at 1500 & 3000rpm CO numbers without being on a dyno?
Here are my other specs:
Dwell 37.2
WRD Tested and working. Sucks in air when cold. No air getting sucked in when warm.
CSV & TTS Testing and working
Linkage to spec as per the linkage tour
Timing (w/vacuum) is 2 ATDC
Timing (w/o Vacuum) is 8 BTDC
Spark Plug Wires: New type. All measured at 1k Ohm.
Coil: Silver with Red Label
Ballast Resistor: Red (1.8ohm)
Distributor: 051 Cast iron (Retard with matching Retard Intake Manifold (vacuum connector on bottom)
Plugs: NGK BP5ES (Based on you recommendation several years ago ;D )
I have not tested timing at 1500 or 3000+rpm yet. Will get numbers tomorrow when fellow member 66andBlue comes over to help.
thanks
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Let's see what the more experience folks have to say, but I wouldn't think the CO w/ and w/o load would be close to the same, i.e. you are running rich. Your bolt should make it easy to experiment - just keep careful track of the changes you make so you can reverse them if needed. And yes, if you lean out across the full range you will need to richen the idle back up
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OK. Lets start with the basic stuff. You have done some pretty good diagnostics but now we have to try and figure out what those numbers are telling us.
What coil are you running? The standard black one or the later blue one? Which distributor is on the engine 051 or 062 ? Which spark plugs are you using - NGK or Bosch? Any carbon core wires in the system - IK ohm spark plug ends?
I am now using NGK BP5ES which about similar to the old Bosch W9DC. No carbon core wires which I often find on the coil wire and no other resistors other than at the spark plug ends. If you have the black coil you can upgrade to the red one and a 1.8 ohm ballast resistor.
If you have the cast iron 051 distributor, it should advance about 10 degrees when you pull the vacuum line off. Do all testing with the lines attached. If you are running the 051 or similar, set your idle timming to about 5 - 6 degrees BTDC. Total advance should be about 35 -36 degrees at 3,000 RPM. The 30 degrees at 3,000 RPM often stated is how much the distributor should advance but you also have to add the idle setting to obtain the full amount.
If you have the later 062, this is a bit more complicated. You should have full vacuum going to the distributor until about 2,200 RPM. The speed relay should shut off the vacuum via the switch over valve and the distributor will advance about 20 more degrees. On this system timing is advanced by mechanical up to 2,200 RPM and then the vacuum advance kicks in. If you have the vacuum line from the throttle body connected directly to the distrbutor, ( like I see on so many cars ) all you will have is about 20 degrees of mechanical advance. The engine will lack mid range power and will be very thirsty. The vacuum line should go from the throttle body to the center port on the vacuum switch over valve and then the outer port should connect to a line that goes to the distributor.
Idle timming should be about 3 or 4 degrees ATDC at idle on this system and you should have about the same 35 degrees at 3,000 RPM. You can set the timing at full advance and then check it at idle which should be somewhere ATDC. If it is, then everything is working. Don't disconnect this system thinking it will work better - it won't. Hooked up and working properly, it's very effective.
Dwell should be 30 degrees for the aluminium distributors and about 38 - 40 degrees for the cast iron versions. The points are designed differently on these two models and the angles are different which calls for certain dwell angles. The point gaps are the same but the dwell angles aren't.
I've seen CSV's leak but they had no outward signs that were. Under the vacuum of a running engine they can do unexpected things.
If you can't get the pump to lean down your best bet is to have it gone through. It remains one of your best investments relative to making the engine run properly. All new engine rebuilds are generally done with a IP rebuild, new oil pump, new water pump, distrbutor rebuild and rad recore if needed. The intent isn't to have people spend more money but rather to have a base line of new parts that you know are going to work for you. If any of these parts were replaced or done a few years prior to an engine rebuild then you probably wouldn't need them.
You shoud also check the usual stuff like fuel volume and if fuel is returning to the tank. This is basic stuff but still important.
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Benz Dr.
Here is the additional information that you requested. I have updated my original post also.
1969 4 speed manual transmission
Spark Plug Wires: New type. All measured at 1k Ohm.
Coil: Silver with Red Label
Ballast Resistor: Red (1.8ohm)
Distributor: 051 (Retard with matching Retard Intake Manifold (vacuum connector on bottom)
Plugs: NGK BP5ES (Based on you recommendation several years ago ;D )
I am definitely confused about the timing specs. There have been all sorts of numbers floating around this forum and suggestions that the book and haynes are incorrect. According to the 280SL book and the wiki timing specs are stated as followed:
Timing @started speed: 8 BTDC (w/o Vacuum)
IDLE: 2 ATDC +/- 1 (w/Vacuum)
1500RPM: 12-19 BTDC (w/Vacuum)
3000RPM: 30 BTDC (w/Vacuum)
Just to double check, which specs should I actually be following? I would have to check again today but I think my car runs better on your specs. I would appreciate it if you or somebody could clear up the correct timing specs. Once 66andBlue comes over today I will post my new timing information at higher rpms.
Also, can you confirm if I can use any CO information at 1500 & 3000rpm from the Gunson CO meter while parked? If not, how to you check for lean and rich at higher rpms? Is it just by checking the plugs?
Thanks for all you help
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2 - 4 degrees ATDC is for the later ignition system with the 062 distributor - so that's correct, but not right for your car.
Use my specs for the 051 distributor at 5 or 6 degrees BTDC at idle. 30 degrees is how much the distributor should advance but you want a total advance number of about 35 degrees BTDC at 3,000 RPM. You may find that you get that amount before 3K or slightly after. The main thing is to have at least 35 degrees total advance. You can check it at 4,000 RPM if you want - it's the total amount that you're looking for.
Sounds like you have all of the right ignition parts in your system. I would change your dwell angle to 39 - 40 degrees. The point gap will be a little bit closer which can help if you have any dwell loss at higher RPM's. This is caused by worn bearings on the main shaft or by a small amount of wear between the main shaft and the cam lobe piece. This can be fixed
but I won't tell you how I do it. ;D
Run you engine and pull the vacuum line off while testing with your dwell meter. If the dwell changes more than a degree or two, the advance plate is worn. Sometimes I can fix them but it's about a 50% rate. It depends on how badly they're worn. All of these wear problems are caused by a lack of lubrication and servicing.
You should drive your car first before doing any testing so the engine is fully warmed up. Most of my testing is done by spark plug colour, the sound of the engine, how it smells while running, and how it feels on the road. A 280SL engine should have a smooth idle, quick throttle response, and should pull hard when you feed it some throttle. The front of the car should lift a little bit and you should be able to feel it pushing you back into your seat. In other words, it's something you can feel as well as hear, when you have it right.
Pull your plugs and lay them out on a table in the order you remove them. If they're black and sooty looking the mixture is too rich. A light tan colour is preferred. The IP should be rich at idle and lean during mid range while quite rich at full throttle. This is mostly done through throtle linkage where the air valve opens faster through the mid range than does the IP.
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Benz Dr.,
Here is the new info with your specs. BTW, my 051 distributor is the cast iron type.
IDLE: 5 BTDC (w/Vacuum)
1500RPM: 23 BTDC (w/Vacuum)
3000RPM: 40 BTDC (w/Vacuum)
Idle was 750-800rpm with the CO reading 4.0 - 4.5%
The engine would miss a little as you rev'd the engine thru it's range while parked.
I then tried something different and set the timing @3000rpm to 35degrees BTDC. The numbers came out like this:
IDLE: 0.0 TDC (w/Vacuum)
1500RPM: 18 BTDC (w/Vacuum)
3000RPM: 35 BTDC (w/Vacuum)
With a little tweaking of the air screw idle was 750-800rpm with the CO reading 4.0 - 4.5%
The engine would rev much better thru it's range with a hint of missing (while parked) once in a while. However, when taking it for a road test the engine missed a lot.
What would cause the missing while driving? I'm thinking it is too lean in the mid to upper range? I didn't get to take the plugs out after the last test drive because it got late.
Thoughts?
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What's the CO now at the higher RPMs? I wouldn't expect timing changes to impact CO, so although you've probably cleared up some ignition issues, I'd guess you still have a mixture problem just like when you started.
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I think the CO numbers are the same as I stated in my first post. It was getting late and I forg0t. I will have to check again. But aren't those numbers bogus anyway since I'm parked and not on a dyno?
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I would think they are good, or at least indicative of the problem you still have. Removing a shim from the barometric compensator will lean out the mixture across the board and could be an easy and interesting experiment. Just keep in mind that it will affect your idle mixture too, but if it improves performance while driving then you will know you are on the right track.
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I replaced the bc with an adjustable bolt for on the fly adjustments. I will be test running the car this weekend and report back.
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Your distributor isn't working right and is advancing 5 dergees more than it should. Go back to 5 degrees BTDC. You probably have fouled out spark plugs.
I think your IP is pooched.
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@benz_dr
Thanks for all your input (also twistedtree) . Can you help me understand your reasoning for setting the timing to 5 BTDC at idle? I have been reading (and trying to comprehend :) ) all of the distributor posts in this forum. Do you think the 280sl just runs better at that setting? Are you trying to compensate for worn parts? It seems that everybody is following the MB Book specs and setting the timing to
Timing @started speed: 8 BTDC (w/o Vacuum)
IDLE: 2 ATDC +/- 1 (w/Vacuum)
1500RPM: 12-19 BTDC (w/Vacuum)
3000RPM: 30 BTDC (w/Vacuum)
Sorry for all the questions. I'm just trying to get a handle on all of this.
thanks much
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Hello,
I would try the split linkage test at higher rpms and see if the engine miss goes away as you induce more air by opening up the linkage going to the venturi. Looks like your upper rpm ranges are rich. You can lean them out easily by removing a shim under the baro. compensator, or adjusting the rack. Since your idle mixture is currently ok, you will need to richen it up a bit with the thumbscrew after the shim is removed.
Shim removal under the baro. is a lot easier than the main rack adjustment on the IP. Also it is easier to put back as before if needed.
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@benz_dr
Thanks for all your input (also twistedtree) . Can you help me understand your reasoning for setting the timing to 5 BTDC at idle? I have been reading (and trying to comprehend :) ) all of the distributor posts in this forum. Do you think the 280sl just runs better at that setting? Are you trying to compensate for worn parts? It seems that everybody is following the MB Book specs and setting the timing to
Timing @started speed: 8 BTDC (w/o Vacuum)
IDLE: 2 ATDC +/- 1 (w/Vacuum)
1500RPM: 12-19 BTDC (w/Vacuum)
3000RPM: 30 BTDC (w/Vacuum)
Sorry for all the questions. I'm just trying to get a handle on all of this.
thanks much
Those are all specs for the later engine with switch gear.
Set it at 5 degrees BTDC for the 051 cast iron distributor.
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I spent the afternoon tweaking the FIP today. Long story short is that after adjusting the pump so the car is running correctly at mid and high range (1700 and up rpm) with nice golden brown spark plugs the idle mixture remains too rich. The lowest I could get it was 9.5% CO (spec is 3.5% - 4.5%). Of course if I removed shims from the WRD or BC the car ran and idled nice but way too lean at the mid and high range. Spark plugs were bright white. This is just another confirmation that these pumps wear rich at the idle.
The only thing I have not checked is if the FIP was installed incorrectly at 20 BTDC instead of 20 ATDC. Is there a way to check this without taking off the FIP? I seem to remember one of these threads mentioning a toothpicks in the injection pump trick to see if it was aligned properly. Maybe that was in reference to something else. I will have to search for that one :D
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Hello,
Idle mixture is easiest to adjust. Just turn the idle thumbscrew, on the back of the IP (with engine off only) a few clicks lean, you should see immediate results in idle mixture. Oval shim removal may only change mixture (all ranges) until the engine is warmed up.
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I guess I was not clear in my post. I had the pump all the way leaned out. I turned the knob CCW as much as it would go. The lowest CO I could get was 9.5%. I could get it lower and perfect at idle if I removed shims from the BC but the leaned out the mid and upper range too much.
For kicks I started increasing mixture (CW) one click at a time and recorded the CO%. As I stated, it started at 9.5% but increased proportionately to 11.3% by click 14. Clicks 14 - 20 resulted in a very rough idle with engine almost dying. The CO bounced around in the 10-11% range during these clicks. I'm not sure what to make of that.
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Yes, it sounds like rebuild time on that pump. If nothing else it will save you an awful lot of frustrating experimentation.
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First, I'll ask the obvious. Sorry. Did you actually engage the slot with the knob when you backed the idle mixture adjustment out? Did you feel it click?
Second, I wonder if you are getting enough air through the idle air screw and the hose. I am suspicious because you said originally that you could not raise the idle.
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Yes, the fuel mixture screw is absolutely engaging. I have actually leaned it all the way out enough to feel the internal screw hit the fitting of external screw. I then turned clockwise enough to make sure everything turned freely. The air screw is opened all the way.
I just got through doing JA17's test to see if the IP was install 180 degrees out of time. Unfortunately, it was installed correctly so it looks like it's going to be rebuilt. It's worn rich at idle.
I will be posting a 'How to" with pics using JA17 method.
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Well, you may be rich at idle because you are not getting enough air through the valve and tubing. Have you checked that out?
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I spent the day today putting back together the IP and getting idle all set to specs.
My timing is now at 2 ATDC (as per book specs)
Dwell 38 degrees
Warm Idle is 650 -750 (digit rpm gauge bounces a bit but engine sounds good)
CO 4%
Warm start is great
I have not tested cold start yet.
Since my IP was leaned all the way out (CCW) I enrichened the IP 15 clicks (CW) so I could have room to play with later. I did some experiments yesterday that showed my IP adjusted the CO % about 2% over 15 clicks. So in theory, I should be able to back down the pump (CCW) 15 clicks (my max lean) to lean my CO% down to 2% (4% -2% =2%)
I used my BC Bolt hack to adjust the IP across all ranges to get the idle CO% down to 4%. I then took out the bolt and measured it and translated that length to my BC. I used a micrometer to measure the bolt and BC but I found that I need to add several more shims (fine tune) to get it where it was. Very easy. Using the BC Bolt Hack make life easy :)
Now with everything back together I went for a short 2 mile drive. The engine sounded great. NO missing. Very Strong! I have gotten the car to this point before but the mid and high range while driving was always too lean. Plugs were bright white.
So...... Before I start messing around with the mid and high range of the IP (Black and white screws) I would like to get opinions if you guys think the plugs are way too lean or OK. I am terrible at plug diagnosis unless it is extremely obvious. ;D
I have attached two pictures. Frankly, they look the same to me. The idle.jpg was after a 5 minute idle at 4% CO. I pulled the plug again right after a 2 mile drive in the other.
What do you guys think of the plugs? Lean or OK?
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I'm with you on reading plugs; it's fine for judging gross problems, but no way to fine tune. For fine tuning, I'd go based on how the car feels, smells, and the CO numbers.
Do I understand that you now have reasonable CO numbers across the RPM range? If so, that's a significant change from where you were before, right? Any idea what you "fixed"?
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You have the 051 distributor, right? It runs great at 2 ATDC? OK............. ::)
5 - 6 degrees BTDC is where you want it. 35 - 36 max advance at 3,000 RPM anmd above.
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For the 051, the BBB calls for
2-4 ATDC @ idle w/ vacuum
12-19 BTDC @ 1500
30 BTDC @ 3000
Dan, it sounds like you've found other numbers work better?
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To give a little back story my engine has always had the incorrect timing pointer on it. I was never able to know exactly what timing I had. It was all done by ear, or diagnostic machine, vac hose method. Not very accurate for me. It drove me nuts. I have been dealing with that for the last 10 years or so. I finally got the correct timing pointer from JA17 so I could see where I really stood. When the engine was rebuilt 10 years ago I was getting about 230 miles per tank. Over the years it has degraded to about 170 mile per tank. I am guessing that is mostly attributed to me trying to tune "by ear". Bad idea.
So 2 weeks ago when I started this whole thing I think I was at 14 BTDC. Whoa! that led me to a broken distributor vac hose. Fix'd that and that put me at 4 BTDC. Then I followed the BBB book and tried setting to 2 ATDC. This introduced some missing at mid to high range. I then moved on to Dan's timing numbers and that eliminated the missing ;D However, I was extremely lean at mid and high range and extremely rich at idle.
The last two days have been experimenting with the IP pump and concluded that I just need an IP rebuild. I talked to JA17 (Joe) last night and he gave me some more tips by trying to adjust the internal mid/high range (black/white) screws inside the pump. I figured what the heck, if I really mess it up the pump is going to be rebuilt anyway :)
So that brings be today. I decided to set everything at BBB specs as I stated above and tweaked the IP pump to get a good idle CO and prepared to go into the pump to adjust the mid/high range screws full expecting it to run very lean as it has previously done before. Which brings me to the two pictures of the spark plugs.
I just got back from a 10 mile drive and it drove great. I am just worried that it's too lean.
So.. Too Lean or OK? I don't want to melt anything ;D If they are considered too lean I then have to start the ugly process of tweaking the internal IP screws.
@twistedtree
The only thing I worked on today was getting the IP idle mixture set correctly. I just set timing to 2 ATDC. Move the idle adjustment screw on the IP 15 clicks from max lean.Tweaked shims on the BC. I was fully expecting to get bright white plugs (too lean) at mid/high range but I got the pictures above which I can't tell are still lean or OK. If they are OK I might be out of the woods :)
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For the 051, the BBB calls for
2-4 ATDC @ idle w/ vacuum
12-19 BTDC @ 1500
30 BTDC @ 3000
Dan, it sounds like you've found other numbers work better?
That's wrong or at least it's not what works right. The 280SL should be 6 degrees BTDC and the 230SL or 250SL won't be any different when using a 051 distributor. 30 degrees is how much the distributor should advance but it's not your maximum advance. For that, you have to add your initial timing amount at idle because the distributor won't be advancing at idle. It doesn't matter how much you advance the ignition at idle with the 051 distributor because the vacuum portion won't advance until you open the throttle. The mechanical portion will start to advance above 900 RPM but this can be changed by adjusting the spring tension inside of the distributor.
The 30 degrees at 3,000 RPM is what you should have while making this test using a distributor tester and is not what you set your ignition at. MB mechanics would have already known this and would have simply added the initial timing advance to the total distributor advance. The BBB wil give you specs but they have to be understood from the point of view that some are to be taken as a maximum and others as part of a total amount.
Another example of this would be cylinder bores. The maximum bore may be 83.5 mm and when you order pistons you order that size. The piston is actually smaller at maybe 83.46 mm but that is already taken into account and they're machined to that tollerance.
As I recall, this patricular distributor is advancing 35 degrees which is 5 degrees too much. So, where ever you set idle timing, it's always going to be wrong at full advance. 2 - 4 degrees ATDC is for the late 280SL and should not be used for cars running the 051 unit.
I'm going to try one more time. Set your ignition to 5 degrees BTDC. :)
Remove the vacuum cell from your distributor and turn the pull rod in one full turn. This should give you less vacuum cell advance but it will not change the mechanical portion. Install the distributor and set your tinming to 5 degrees and check your maximum advance which should be around 35 to 36 degrees BTDC. If It's more than 36 degrees remove the distributor and do the pull rod adjustment again but only turn it a half turn this time.
Repeat setting the timing and checking what you have for full advance. When you get it to 35 - 36 degrees lock the distributor in place and don't mess with it after you have this amount.
Looking at your spark plug pictures they look about right and maybe a tiny bit rich which is OK for now. You will need to drive the car for a while while checking the plugs but frankly, a pump rebuild would be your best option here. You may be able to get it close by working on it but I've never been a big advocate of playing around with such a delicate piece of machinery.
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.... 2 - 4 degrees ATDC is for the late 280SL and should not be used for cars running the 051 unit. ....
.... or perhaps he says - they say. ;)
The 1969 Mercedes Technical Data Book clearly specifies 2° +/- 1° after TDC with vacuum even when installed in a 230SL.
Obviously "late 280SL" did not yet exist in 1969.
So, who is right? ???
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I know what the book says and I'm not following it because it's 40+ years later. 5 degrees is where the engine will make power. It will run at TDC just fine but it will use more fuel and won't pull as hard. :)
I run my own car at 36 degrees. I had it at 30 degrees and it never seemed to have very good throtttle response. :(
After studying ignition systems on these old cars for about 20 years now I hope I've got some of it figured out. There's a sweet spot where every engine runs really good and it isn't TDC or anything after that unless it's a late 280SL. Clearly, if you hear pinging, you have it advanced too much or you need higher octaine.
I use regular in my car and it never pings at 36 degrees. I haven't checked my compression in a while but the last time I did it was up around 175 PSI. I set the advance springs in my distributor a bit tigher than stock so it would advance slower which is why I can run regular. The car gets a consistant 26 MPG ( IMP ) every tank.
The car is a '66 230SL with the ZF 5 speed. I used a distributor from a 300SE that's dual point - dwell angle is 52 degrees. Each set of points runs three cylinders - throws a wicked spark with the red coil and ballast resistor set up. I'm running a 230SL cam shaft advanced to 12 degrees BTDC.
Last year I changed out the 4.08 rear axle to 3.92 LSD and I picked up a bit more mileage.
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Well.... I guess I have come full circle as far as I know. Last night I put the car away knowing that it was idling (warm) with a nice 4.0% CO. Today I wanted to see what it would do completely cold. It started right up and quickly went lean to about 2.0% CO and stumbled as it got warm. After the engine was completely warm (no air sucked into the WRD) the CO was still 2%. Mind you, I have not touched anything since the night before when everything was running perfect at a CO 4%.
I then clicked the IP idle mixture screw (CW) one click to enrich the mixture. Boom! the CO% is not back up to 4%. Everything runs nice ???
Now it gets stranger. I let the car sit for a couple of hours and get completely cold again. Start it up and the CO is back down to 2%. Again, I clicked it one more time (CW) to enrich it. This is +2 clicks rich from last night. The CO% popped back up to 4%. It seems like I'm just chasing it now. ???
All this leads to the conclusion (like we didn't know already) that the IP has something really funky going on with the idle mixture and needs to be rebuilt. The IP mixture seems to float or get readjusted after the car engine turns off. It's almost like something in the pump is broken, loose, or bouncing around, or stuck spring.
Other than pulling the pump and getting it rebuilt can anybody explain what it going on or seen this type of behavior?
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Hello,
Things take time to settle in after radical adjustments. Moving parts are getting to know each other and new locations. Fuel varnish build-ups are worn away as parts settle in new locations.
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Hello,
Things take time to settle in after radical adjustments. Moving parts are getting to know each other and new locations. Fuel varnish build-ups are worn away as parts settle in new locations.
I think I'll start using that answer from now on. ;)
'' Yep, them there new parts is gettin' to know each other. It'll improve once they get better aquainted. '' ;D
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After 43 years, I think those parts are very well acquainted and they just don't like each other anymore ;D
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After you make those adjustments, are you driving the car for several mnutes? I have always found that when changing the idle mixture screw, the engine wants to be driven before the final results are to be seen.
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Yes and no. It really does not seem to matter. I have discovered a pattern but it really does not make sense to me.
Start car stone cold (starts right up)
- CO is about 4%
As car gets warmer the CO% gets leaner to 2%
Turn the FIP idle mixture screw +1 click CW to enrich
CO% is now back up to 4% and everything is good.
Drive or Sit for a bit. Park. Wait a hour or so for stone cold.
Start the whole process over. ???
I started at 15 clicks from max lean at the beginning of this process. Now I am at 20 clicks CW from max lean. It seems like something is resetting internally in the pump.
I don't know how it can go lean as the car warms up either. The WRD shuts off the air. It should go richer, right? And I certainly don't know why the FIP idle has to be turned one turn CW each time I do a cold start. I can't imagine what funky thing is going on inside the pump to make that happen.
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Think how happy you would be if your rebuilt FIP arrived today ready to install :-)
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Last fall I spent a lot of time on a 230SL getting the warm-up right. When I finished it had a very good warm idle at around 4.5%. The next day I started it and it was around 3%. I varied from time to time between 2.5% and 5.5%.
I asked Gernold about this, and his answer was a worn throttle body will allow slightly different amounts of air past it when it is closed. It takes only tiny amount of air to change the idle CO.
Also, if you are using a Gunson Gastester, they are only accurate to .5% even when calibrated.
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Here is an update to my magical mystery FIP ;D
I will start off by answering a question that I asked in a couple of posts above. After taking a break it came to me that the FIP does lean out as it gets warmer (not richer). I was thinking it was getting richer do to less air getting sucked in from the WRD but I forgot that the WRD also pushes down on the FIP rack as the engine warms leaning the CO%.
As a result, the partial behavior I described does seem consistent with how the FIP should work.
I started from scratch yesterday and have come up with better result albeit not perfect.
From a cold stone start in the morning.
-15 second fuel pump prime
-Turn on engine (fires immediately) and idles on it's own
-CO% 6
-As the engine warms the WRD slowly stops sucking air until completely shut off. At the same time, the CO% slowly drops from 6.0% to 2.1% and engine dies (of being too lean i guess)
-I then try to restart the engine (rough idle) and it needs a lot throttle help to keep it going.
-I use high revs for about 10-15 seconds before the engine starts idling on it's own at CO 4.0%
-I then take it for a 10 mile spin going to thru all the gears and getting the final warm up at 180 degrees
-I come back home and retest the CO% ant it's back at 6.0%
For some reason it really likes to go down to 2.1% when it's cold no matter where I set the idle CO%. I'm not sure what that really means. I can understand it dropping down a relative amount from the starting CO% but it likes 2.1%.
Is it possible that the WRD is shutting off it's air intake and leaning out the FIP way too soon before the engine gets at the required operating temp thereby getting this funky behavior? I know that the internal shims in the WRD can control WHEN it shuts down the air and how much it really leans out the pump when thermostat pin fully extends.
@ctaylor
Thanks. That is an interesting explanation. It certainly is a possibility.
@wwheeler
Thanks. I took your suggestion about driving after every adjustment of the FIP. It seemed to help and got me to where I am at today :)
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There is another recent WRD thread on this site that talks about the condition where the engine is warm but not hot. There were about three people from what I recall had this issue although each acted differently. While I haven't had a chance to break out my Gunson tester, I used the spilt linkage method to determine lean or rich.
My cold engine starts rich as expected and as it slowly warms and the RPMs drop, the mixture gets closer to balanced. In the time between "fully" warmed up and somewhat warm, the engine runs lean. Not to the point where it dies, but lean enough to run rough and slower. If I rev the engine enough, after a while it will warm so the mixture will richen and then it is balanced and runs great.
What I normally do when starting the cold engine is let it idle until the RPMs drop for the first time usually around 130*F or so. I then take the car and drive it. The engine does lean and slow at idle for just a bit while sitting at idle, but the throttle solenoid (automatic) keeps the RPMs up enough. After that brief time, it runs fine. So the lean period is much shorter then when letting it idle in the driveway.
I have lessened the lean effect by adding .003" oval shims to the WRD. If I add too many though, it runs way too rich when very cold and the fast idle isn't very fast. Maybe I am being too picky (I have been accused of that before ;)), but it would be nice to have it right. The gunson tester should help me fine tune it, but for now it is as close as I can get it by feel.
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In most cases you will probably sart your car and drive away shortly after. Getting it close is usually all you need because your main objective it to get the engine to start, right? As long as it continues to run the engine should be fully warmed in a few miles or less.
Starting is important of course, but driving impression while fully warmed should be your main goal. Once you have that, then maybe you can try a couple of diffrent settings to improve cold start idle and warm up. I wouldn't fixate too much on this brief running peroid unless your engine stalls or is belching black smoke.
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Maybe you are getting a small amount of air past the valve during your driveway idle warm-up. Then with full warm-up. the valve is pushed down far enough to completely close off the air.
If you look at the diagram on 07-14/13 in the BBB and also in the Haynes manual at p. 72, you can add a compensating washer to move the slide valve down a little further and shut off the air earlier.
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You may notice brown varnish deposits on the back side of the camshaft lobes. This varnish build up happens in areas not in use. The high points of the camshaft lobes are bright and polished. These areas are in contact with the rocker arms. Making radical adjustments to the IP moves internal parts to areas not normally used. These areas most often have varnish build up like the camshaft. When I mention that "the parts need to get to know each other" I am referring to the varnish situation. A short test drive as Wallace suggests allows the parts and new settings a chance to "get to know each other" in other words, wear the varnish off.
Drive the car a bit then get back to the fine adjustments.
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A very good update! ;D
I would like to first thank everybody that has offered suggestions. I could have not done it without you guys :D I know that sometimes it gets tedious dealing with the same old problems but it's definitely great to talk them through.
After I kept getting no where with the FIP I decided to follow WWheeler's advice and focus on the WRD a bit. I found this thread which I think he was referring to:
http://www.sl113.org/forums/index.php?topic=9244.0
Mind you I had always ASSUMED (yup, you know what's coming) that the WRD was working fine based on the air suction stopping as the car got warmer. After reading the WRD thread I decided to take it apart to see what was really going on if anything. I wanted to see how many "round shims" were there. When I first opened up the WRD I could see an original round shim at the top just underneath the retaining clip. Upon removing the retaining clip and removing all the shims I found 3 additional homemade shims :o. There was a total of 4mm of shims in there which if I understand correctly is too much. I then put back 3 original shims totaling ~1.30 mm. (1mm, .1mm, .2mm)
I then started from a stone cold start. The air being sucked into the WRD seemed louder now. The other thing I noticed is that it took much longer for WRD to shut off air intake from before. Also, the WRD air intake did not completely shut off when just idling as it did before. The engine really had to be warm. I took the car for a quick spin and by the time I came back the WRD air intake was completely off.
While I was doing all of this I was monitoring the CO% with the Gunson. At the cold start, it fired immediately, and the CO% rose to 11% over 50 seconds. After 20 more seconds the CO% started dropping. Over the next 2 minutes the CO steadily declined to 1.5%. As it declined you could hear the WRD air intake slowing closing to the point of just shy of completely closed. This is where I decided to take the car out and get it 100% warmed up. Upon returning the WRD air intake was completely closed. ;D
I now decided to move back to the FIP tuning. The adjustments I was using were shims under the BC and the FIP idle mixture screw. This was quite the iterative process but satisfying because things starting working as they are supposed to do. I started with a 2mm shim (original?)under the BC and ended up with adding an additional 1.5mm for a total of 3.5mm. I added a 0.15 shim each time in conjunction with dialing down the FIP idle mixture screw.
After doing all the adjustments (and driving in between) I settled on a CO of 4% ;D I think I that took me to almost MAX Lean on the FIP idle screw.
When I started all of the adjustments this morning the car would slightly miss every once in awhile and ONLY on hard acceleration. I diagnosed this (correctly I think?) being too lean in the mid and upper ranges. As I added shims under the BC(more rich) each time the missing slowly disappeared. The missing is 99.9% gone now. Now, I could add more shims under the BC to enrich the FIP over all ranges to possibly make it 100% but as I stated above I think I'm all out of FIP lean clicks. I would like to avoid going into the pump. I will drive for a bit and let everything settle. Overall, I am extremely happy with the results. ;D
There have been many things that I have learned from this thread. But the two diagnostic tips are
1) Just because your WRD completely shuts down the air suction as it warms up doesn't mean that it is actually running or calibrated correctly.
2) As most of you stated, it's extremely important to drive the car after you make FIP & BC shim adjustments to let things "settle" and find their place. I saw a difference every time.
I did have a question regarding the cold start idle mixture starting at 11%. Is this typical and in spec? If anybody has a gunson meter and is willing to do a quick test(or if you just happen to know) I would like to know. I'm just trying to dot the "i"'s and cross the "t"'s so I can close the book on this thing ;D
This is the plug color I ended up with. What do you think?
(http://www.sl113.org/imagebank/thumbs/mrfatboy/img0331.jpg) (http://www.sl113.org/imagebank/?v=mrfatboy/img0331.jpg)
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mrfatboy,
That plug looks pretty good and that is what this Group is all about, helping each other and keeping these cars on the road. ;)
Now if you would like to become a full member and then you can do a write up to go into the Technical Manual ;D ;D
Giving what country you are in and area is good too 8)
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Hj J just read this posting completely and the plugs look good to me , note if you have haynes manual usually there is a photo of spark plugs in the back inside cover & will give you an idea at what shoud be correct.. It is a little Iffy to know after only a 2 mile drive .. I would run it at speed on the open road for about 10 mile drive to know where you are really at.. and compar the plugs at that time to the pictures in Haynes. and dont let it idle a lot .. shut it rite off after your drive. Good luck Clembeauch 63 712
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If you could take a picture of your spark plug from the side with the ground electrode pointing up, that would be better. I can't tell by looking right at the end of the plug due to shadowing. It's not too lean but I can't tell how rich it is because the shadows are about the same colour as sooty deposits.
I found that my own WRD wasn't quite shutting of just like yours. It really doesn't take much to create enough of a vaccum leak to make you question what's wrong.
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Something else that comes into play with WRD; and that is the cooling system thermostat. Because Texas is very hot in the summer (especially last year), I installed a 167*F (75*C) thermostat to keep the engine cool when driving on the highway and in heavy city traffic. When starting the engine this winter (about 50*F ambient) with the 167* thermostat in my garage, I could not get the engine hot enough to shut off the WRD valve completely. So what ctaylor738 is saying, is correct. The WRD thermostat never completely warms up until it is driven. The only way to REALLY get these engines completely hot is to drive them. It won't happen in the garage alone.
I have made more mixture adjustments than I care to admit, and everytime it will change after a drive.
And as Garry says, become a full member. It is the best investment you will make in your car!
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The WRD, as the coolant heats up from ambient to 75 C(in 60 sec or so), simultaneously closes off WRD air and reduces FIP fuel to 'idle' rate. Hopefully, Bosch and the WRD maker made the fuel/air ratio correct across the range......
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Well guys, I went for broke today and tried to tackle my Cold Start idle issue now. I am very happy with how my warm idle and CO turned out but the my cold idle is about 600-700rpm with my CO at starting 11%. As I stated above, as the car warms up the CO comes down to 1.5-2% and not it until I drive it and get it completely warmed up does it come back to 4.0%. I'm assuming the CO dip to 1.5-2% is being caused by the last little air gap in the WRD until it completely closes.
Rereading the thread I posted above about the WRD I decided to take out the 2 oval shims under the WRD (.12mm & .63mm) in order to minimize(try to get leaner) the 11% CO during warm up and increase the rpms. If I understand the post, the oval shims control fuel mixture at warm up. Removing shims making it leaner and adding richer. So after removing both shims and doing a cold start as I have been I saw absolutely NO difference in CO% and idle speed. Everything was exactly the same (11% and 600-700rpm idle)
I would have thought removing the oval shims under the WRD would have leaned out the CO by at least some amount during warm up. How would you interpret no change at all? The only thing I can think of is to add round shims BELOW the air valve slide in the WRD thus extending the pin further in the FIP leaning out cold start mixture? Is that really an option?
I see that WWheeler had the exact same problem in this post http://www.sl113.org/forums/index.php?topic=11647.0.
Suggestions on what to do next?
BTW, I copied and pasted the wrong WRD reference thread a couple of posts above. I have corrected it.
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Sounds like your WRD is at its upper limit.
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If I understand it correctly, the WRD internal spring is not totally compressed until full warm up, correct? As the spring is compressed by the WRD feeler pin, the air valve is slowing closing the air intake AND leaning out the mixture. If I start at a CO of 11% cold and it finally sits at 4% warm that suggests the WRD internal spring is not MAXED out (compressed) yet when cold.
On the flip side, let's say the spring was pre compressed at the stop pin and I had now where to adjust. That would not explain the CO currently going from 11% to 4% during warm up. The only other thing that is changing is the air intake is closing and if the internal spring is all ready compressed how would the FIP continue to lean out the pump to 4%. It would get richer due to less air and the same fuel going thru the FIP.
Is it correct in saying that the internal WRD spring hits the stop pin (fully compressed) when the car is completely warmed up? Before? After?
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I went ahead and preformed two more tests for a total of three to try to get the cold start better. All three tests were stone cold starts. My goal was to lower the CO% at warm up while raising the warm up idle hopefully to 1100.
My baseline stats were as follows:
-Cold idle 600-700rpm (idle never was higher)
-CO started at 6% and immediately climbed to 11%
-Over a 4 minute period the CO dropped to 1.5-2%
-Drove car for final warm up and ended with a 4.0% CO with idle 600-700rpm
Test #1
I removed the two shims under WRD in hopes of leaning out the fuel mixture during warm up. Started cold and saw no difference in baseline.
Test #2
With the WRD oval shims still removed I added a 1.15mm shim UNDER the air slide valve in the WRD. See picture below. Started engine cold.
-Cold idle 600-700rpm
-CO started at 6% and SLOWLY climbed to 11%
-After 4-5 minutes I didn't see any change in CO. I assumed that I messed up and maybe the air slide valve got stuck or something. I ended the test.
I then took apart the WRD and found everything working correctly. As I later found out, the time before the CO to start to drop was much longer.
Test #3
I decided to try a smaller shim under the air slide valve in the WRD. I went with a .85mm shim.
-Cold idle 600-700rpm
-CO started at 6% and SLOWLY climbed to 11%
-I decided to wait a while for this warm up to see if it would eventually come down. It did. It was noticeably longer than the baseline.
- Idle started to rise to 1000rpm over a long period of time.
- The CO eventually came down to 2.5% with an idle of 1000rpm. I had to rev the engine a couple of times and it finally dropped to 650 -750rpm.
- Went for a drive and the CO retest was 4.5%
During the Test #3 drive I noticed that the car started missing a little again on hard acceleration suggesting it went a little leaner over all ranges. Removing the oval shims and adding a round shim under the air slide valve would make mixture leaner but I thought it was only supposed to affect the warm up mixture. ???
I found it interesting that none of my tests affected the CO during warm up. The biggest difference seemed to be time.
I really wish I knew what the CO% was at cold start for a properly tuned car. For all I know it really is supposed to be 11% and I am looking in the wrong place. Please jump in if you have the answer ;D
At this point, I have come to a dead end unless somebody offers a suggestion or another test to try. It just might be that I can't compensate anymore for a worn pump. If not, I think I will call it day and just be happy what I have.
(http://www.sl113.org/imagebank/thumbs/mrfatboy/img0334.jpg) (http://www.sl113.org/imagebank/?v=mrfatboy/img0334.jpg)
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I think Dan said the same thing earlier in this or perhaps another thread, so I may be repeating.....
I would focus exclusively on tuning at full operating temp and get that working 100% first. The only caveat is to ensure the WRD is closing completely when you do this tuning, but otherwise forget about the warm up cycle.
Next I would follow the BBB guidelines for adjusting the WRD internal shims to cause air shutoff to occur at the correct temp. This can be done on the "bench" so to speak, though in my experience that means the kitchen.
And I wouldn't pay much attention to warm up CO. I think it should be higher than normal, but as you point out, who knowns how much higher. I'd be looking for a faster idle and acceptable running, then declare victory.
The challenge with the IP is that all the inputs are interrelated, but we don't know exactly how. There is a stop for the WRD enrichment lever, but we don't know when it should be hit, nor do we have any good way to tell if it is being hit. If that lever is not against it's stop, then the WRD presumably impacts mixture at all ranges. It get very complicated very quickly, especially when it's a black box.
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Currently I'm fine with how it runs when warm. I was just trying to get the cold start in spec while I am feeling motivated ;D I thought I understood from the other WRD thread that WRD pin DOES hit its stop when the car is warmed up. Maybe I misunderstood. It makes sense that it would. You are absolutely right about everything being interrelated. I have an extra pump on the bench that I check all the movements and measurements. There just so much you can do before all the interrelationships get out of whack.
The only other experiment I could try (short of putting a plexiglass cover on the side of the running pump to see what is going on) is removing the WRD completely and put an adjustable bolt in there. That way I could check if the WRD pin truly hits the stop when completely warm. Maybe I just haven't added enough shims. I think the recess in air slide valve is about 2mm. Adding anymore shims would allow them to slip out.
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Hey Fatty,
Nice to see you as a full member and welcome aboard. Quite a few from Southern California now.
Garry
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Thanks. BTW. I lived in Melbourne for a year when I was a kid. ;D