Injection pump throttle return?

[Shvegel]

Good spotting.  I wonder if somehow they tried an odd way of  setting the pump up and forgot to take them out.  I have never heard of anywhere close to that many shims.

[ja17]

Tom, McMaster Carr has various metric shim thicknesses for little money. I think I use the 14mm I.D. round shims.

[Tomnistuff]

There appears to be light at the end of the tunnel.  My original thread was "New engine startup - NOT", but I got hustled over to a new thread (this one) by the "dragging and sticking" of my IP throttle lever during a split linkage test and the need for a supplemental throttle linkage spring to fix it.

Anyway, having finally discovered the Barometric Compensator shim problem, I started trying to set up a test program to get the car running and get things done in preparation for Meeting of the Clans II, with the help of many of you.  My last few days have involved buying a new battery, hold-down rods and battery charger.  It seemed that every time I fixed a problem, I turned my back and another problem bit me in the butt.

Today I ran some shim removal iterations. 

First test:
I removed the thickest two shims (0.0795 inch and 0.0770 inch), leaving 4 shims totaling 0.0850 inches.  By the way, since I'm using a digital caliper, the last digit keeps changing by 0.001 or 0.002 inches.  Results:  It started immediately and ran up to about 2,000 RPM.  With the split linkage test, air made it run lots faster but fuel almost caused it to stall, so it was still rich.
I shut it off immediately but was very happy to see there was no smoke in the garage and the running was very smooth.

Second test:
I removed another shim (0.0225 inches) leaving three shims totaling 0.0625 inches.  Results:  It didn't want to start until I reduced the idle air flow from when I had raised it a few days ago due to the smoke filled garage.  It then started immediately and ran cleanly up to 1750 RPM.  Vacuum was 16 In. Hg.  The split linkage test crudely said it was pretty well balanced although really fast.  More air brought the speed down and more fuel brought the speed down also.  Again, NO SMOKE and RUNNING SMOOTHLY, but still way too fast.  In accordance with Joe Alexander's advice, I burped the cooling system with the top radiator hose.  It burped once then drank lots of coolant from the overflow tank.  Eventually that problem will go away too.
Again, I was very happy.  It's still running too fast to worry about small changes like the IP idle mixture screw so I'll take out another shim tomorrow, and reduce the idle air flow to try to maintain the fuel/air balance by Kentucky windage.  Hopefully I can get the speed down to within the trimming range or until shim changes don't help.  I'm still working only with the Barometric Compensator.  I haven't touched anything else.

At least there is not more smoke in the garage and my plugs are staying clean.  I'll check them tomorrow to see if they are cleaning up a little or if i should change them again.

The car is getting close to driveable finally.

By the way, I've blown three #6 fuses today, all during the first few seconds.  Something isn't right with the cold start electrical circuit.  At least it doesn't keep me from running the tests.  I'll start diagnosing it when I've got the idle speed and fuel/air ratio under control.

I'm going to quit for the day.  Goodnight.  At least it's a holiday here tomorrow (St-Jean Baptiste)

Tom Kizer

[Tomnistuff]

A new day and the 3rd thru 8th iteration of shim removal followed by two IP idle screw adjustments.
One at a time, I removed all the shims and the idle speed kept dropping with each shim removed and its corresponding idle air valve adjustment.  The last shim removal resulted in an idle speed of 600 RPM and 16 in. Hg. Vacuum.  The last shim removal dropped the speed from 1200 RPM to 600 RPM, so I couldn't really keep the last shim.

So I enriched the IP idle adjustment screw two notches, which resulted in 950 RPM and 15 -16 in. Hg. But both speed and vacuum were unstable.  Leaning the screw one notch (still one notch richer than rebuild level) and rebalancing air and fuel with a split linkage test yielded:  950 RPM / 16 In. Hg. Vacuum, with all values very stable.

With new plugs, I followed up by verifying, with my timing light, the spark timing that I had set statically a few days ago.  I'm running Premium fuel, so I'm not going to worry about the two extra degrees until the cause me a problem.
The value is 32 degrees BTC with no vacuum line.

Once it's warm it's quite good, but it's still blowing #6 fuse every time I start the car, so it's difficult to start cold, even on a nice day like today.

It's cold start devices electrical diagnosis time.

Thanks for all your help and advice for getting it running warm.

Tom Kizer

[Benz Dr.]

Put your vacuum line back on and adjust timing to 38 - 40 degrees BTDC at or above 3,000 RPM. Removal of the vacuum line is only for testing.

Your vacuum reading sounds a bit low and should be more in the 18 - 20 inches range on a fresh engine which will be fixed by more ignition advance.

[Tomnistuff]

Hi Dan,

I was afraid you would say that.  I know you are right but I tend to get all puckered up when I rev an engine to high RPM's with no load, although I know it's not supposed to do any harm at 3,000 RPM.  I'm also afraid of high voltage, so I'll have to adjust the distributor while in a state of anxiety.  When I was a young fuel systems engineer at Ford, I used to regularly break the rules by looking down into a carburetor while the engine was running 6,000 RPM on a dynamometer.  That's when I was immature but immortal.  I stopped doing that when one day when while I was not in the test cell, one of my test engines failed a rod and an oil pan and set off the fire extinguisher system in the test cell.

First, as an excuse not to do what you say I have to do and to provide time to build courage, I'm going to try to discover why the circuit on fuse #6 is blowing fuses the instant I hit the starter, even though fuse #6 is not necessary to start the car.  As far as I can see, it only fuses the heater blower, automatic starting aid and electromagnetic starting valve, which I think means heater blower, CSV and IP start solenoid.  If I'm wrong please correct me.  I'm confused by the multiple and varied naming of devices.  I think the clue to the problem is in the fact that it's a 25 Amp fuse.  What needs 25 Amps?  It must be a secondary power draw or a short circuit to another power draw like the starter.  Or some severely damaged relay or switch.

Anyway, I'll find it.  And thanks, i think, for reminding me.

Tom Kizer

[Tomnistuff]

Sorry, Dan and everyone else.  I was wrong.  I got overconfident.
I still haven`t found the reason why I`m blowing out #6 fuse every time I crank the engine.  It's true that it's supposed to handle only the heater blower, the CSV and the IP Start Solenoid, but I went back and searched my 50 page Assembly Sequence document and found that I had connected a heavy wire to #6 circuit that feeds power to what I've called an Accessory Switched 12V Power Distribution Barrier Block.  It's a small box full of places to access switched 12V to run little accessories like a backup camera, a front camera, a GPS power supply, heater and AC blower motor (note that the original heater motor and switch is no longer connected), and a vacuum cruise control "control circuit".  Then I saw something really stupid.  Downstream of the 25A fuse (#6), there's an in-line 30A fuse for the AC blower motor.
I still can't figure out what is happening because none of those things are turned on, so they are not drawing any power.
Anyway, until I started removing shims from the Barometric Compensator, none of my attempts to start the car brought me to notice that #6 fuse was blown.  That's probably because until then, the IP, with the BC 6 shims, was so rich that non of the non-working cold start devices were even noticeable.  Remember that all of my significant leaning out of the fuel system happened in the same day.  The sequence was: Start the engine rich, try to keep it running to do a split linkage test, stop the engine, remove shim(s), restart the engine which is now warmer and still rich, do another split linkage test, stop the engine, etc., etc.  By the time it was really idling nicely, it was also at running temperature and restarted instantly.
The next day, it took forever to start because: 1) it was room temperature (cold), 2) too lean to start easily without the cold start devices working.
When I noticed the blown #6 fuse and replaced it, the next time I cranked, I used the remote starter connected between the B+ and the "G" terminal on the TTS.
My ear was really close to the #6 fuse when it went "POP".
Now, here I am trying to find out why.

Since my 230SL is a manual transmission, my #3 fuse is connected to nothing.  I wonder if I can reconnect that "Accessory Switched 12V Power Distribution Barrier Block" wire to #3 fuse, which is unused, with another 25A fuse and run the #6 fuse with only the CSV and IP Start Solenoid.

Any opinions?  Right now, I'm a retired mechanical engineer drowning in an electrical engineering lake.

Suggestions?  I'm looking for reasons why what's happening is happening, but I am also looking for solutions without purist prejudices.

Tom Kizer

PS: I've checked all the cold start devices except the WRD and the TTS hot resistance values but that's next.  Everything else checks out perfectly including the wires from device to device and from the battery.  The WRD doesn't draw power so that should have no effect.  WRD requires coolant draining which I'm doing now.

[Benz Dr.]

Only stick fuses where they're supposed to go. I would imagine that the wiring going to a 25 amp fuse would be considerably heavier than one going to an 8 amp fuse.

Look at anything that's not stock to your car. Electrical tape and cheesy wiring would be my suspects.

[Tomnistuff]

I have a question about the TTS testing.
My test results compared to the Tech Manual objectives are:

Resistance terminal G to ground < 35 deg C should be about 20 Ohms and is 32.5 Ohms
Resistance terminal W to ground < 35 deg C should be 0 Ohms and is 0.6 Ohms
Resistance terminal G to ground > 35 deg C should be about 60 Ohms and is 64 Ohms
Resistance terminal W to ground > 35 deg C should be about 100 Ohms and is 130 Ohms.

Do these results sound within reason?  Should I be concerned?

Also, In an attempt to lighten the load on my system, I'm looking at using an unused fuse circuit - #3 which I think is used only for auto transmission cars.  Mine is wired to nothing.  I upgraded my car to a 1.9HP starter, a 55 Amp alternator and a 280SL regulator.  I hope I haven't screwed things up.

Tom Kizer

[Tyler S]

Tom. If you have upgraded your alternator to 55 amps please please replace the 10 gauge wire going from the back of the alternator through to the starter post. The 10ga wire is only good for 30 amps. This is an achilles heel area of the electrical system. If your alternator ever full fields because of a dead battery or jump start then this wire can melt and potentially catch fire. Replace it with an 8ga or above. 

[Tomnistuff]

Hi Tyler S,
I really appreciate your post.  It really shows that you care about others.  It also prompted me to look at my previous posts to see what gage wire I used when I repaired damaged wire at the same time I changed the alternator.  I found it by searching.
I had forgotten that you and I both participated in the same conversation in my old thread entitled, "Potential Repeat Disaster Prevented" in 2015.
I don't know how to post a link to this thread, but the title is above and I found it by searching, "starter wire".
Thanks again.
Tom Kizer

[Tomnistuff]

Back in reply #4 of this thread, I mentioned that I noticed that my oil pressure gauge had stopped working.  Actually, apparently when I discovered the problem, It had not worked since I took the car apart eight years ago.  While waiting for a new oil pressure gauge to arrive, I pressure checked the metal line from the hose to the gauge.  It was blocked or kinked.  Nothing passed.  I ordered a new one in a panic.  Meeting of the Clans II is getting too close to wait.

While waiting for the line to arrive, the gauge arrived so I started to remove the instrument panel.  I removed the line and spent a few "nothing else to do" hours trying to unplug it.  I finally succeeded with Rust Remover, WD40 and finally galvanized wire from the hardware store.  Apparently there was nothing wrong with the gauge, so I wasted a few hundred dollars and a week waiting.

At least that problem is fixed now and I've got 3 Bar pressure after a few seconds of cranking.

Regarding the cold start problem and the constantly blown #6 fuse, I rewired the underdash to take all the new stuff off of fuse #6 and put it on the unused circuit where fuse #3 would go.  That means that the heater blower is also no longer on fuse #6, since my AC system is on fuse #3 along with the cameras, GPS power and cruise control.

After putting it all back together, I tried cranking again and instantly blew #6 fuse again, with nothing on that circuit except the wire to the cold start relay, the time switch, the cold start valve, the IP start solenoid and the famous thermo time switch.

With only one wire being fed by fuse #6, it still blew the fuse during about 2 seconds of crank.

Tomorrow has to be the big day.

Wish me luck.

Tom Kizer