Author Topic: Engine Idle adjustment (Read 16234 times)

230slhouston · « **on:** October 28, 2007, 19:50:36 »

Now that my car is started and the IP plungers are eased out, it is not misfiring. Problem is high idle, 1600RPM at 80 engine temp.

Where is the idle adjustment screws or what is the sequence?

Thanks
MBP.

merrill · « **Reply #1 on:** October 28, 2007, 20:07:29 »

MBP,
so, 1600 is really high, is this after the car has warmed up to 80c?
When warm you should not hear or feel the air at the WRD air filter
on top of the pump.

IF the car is warm and the wrd air filter is silent, If your car is like mine, there is a small hose that goes from the air filter to the intake maifold. there is a screw at the maifold side.
turn in the screw and the idle should drop.

Note: the butter fly in the tb should be closed and the inj pump linkage should be closed. essentially you can have all linkages disconnected and set the idle.

once you get the car idling, do the richness test. you may need to adjust the mixture.

Matt
Austin Tx
66 230 sl - "white"
78 300 D - Blue
98 C230

230slhouston · « **Reply #2 on:** October 28, 2007, 21:32:50 »

Matt,
Thanks for all the feedback and help.

The idle is after the car has warmed up to 80.

Is the screw you are referring to the one on the butterfly intake? I tried adjusting this, the butterfly is cannot be closed anymore.

How do i do the richness test? Do I need a gas meter?

Are there any pictures that show the adjustment areas anywhere on the forum?

Thanks

MBP.

jameshoward · « **Reply #3 on:** October 29, 2007, 02:04:34 »

MBP,

Use the search tool; check using "rough idle" and "richness test." You can also search by members; I'm just coming out of the situation you find yourself in so a quick look at a number of replies to my recent posts might help. Look under ja17's posts for FI pump tour.

JH

merrill · « **Reply #4 on:** October 29, 2007, 12:01:01 »

MBP,

the idle air screw is over near the intake manifold.
you should have 2 hoses coming from your air filter box,

1 large that goes to the throttle body
2 much smaller that goes over near the thermostat. this hose actually connects to the intake manifold itself. there should be a large flat head screw with a spring beneath it.

this screw controlls the air flow to the motor when running, screwing it in reduces the air thus lowering the idle.

note: if the car is too lean the scew looses its effectiveness.

to do the richness test, disconnect the lingkage from the inj pump that goes up to the cross linkage.
then once the car is warmed up, press down on the cross linkage thus opening the butterfly.

if the car revs really hight = rich
if the car revs a little then you might be close.

matt

Matt
Austin Tx
66 230 sl - "white"
78 300 D - Blue
98 C230

J. Huber · « **Reply #5 on:** October 29, 2007, 13:51:55 »

I have found the following link from Pagoda113 to be very helpful. It was created by one of our faithful Pagoda Emeritus. And I wonder if he'd be willing to let us repost it here -- as I tend to refer folks to it a lot! GD?

http://pagoda113.com/eve/forums/a/tpc/f/3296041521/m/7246004272

James
63 230SL

Peter van Es · « **Reply #6 on:** October 30, 2007, 02:46:43 »

Hi James,

we have our own index.php?topic=5003]linkage tour[/url] (with pictures) which covers most of that topic.

It is the next section I'll be adding to the Technical Manual. Then George can add content from the Pagoda113 post to make sure the total is as correct it can be...

Peter

Also known as 'admin@sl113.org' and organiser of the Technical Manual (http://www.sl113.org/wiki/pmwiki.php). Check out http://bali.esweb.nl for photographs of classic car events and my 1970 280SL.

glennard · « **Reply #7 on:** October 30, 2007, 21:34:21 »

Idle adjustment.-- Base conditions- Engine is warmed up, only air source is thru the idle air valve(butterfly is closed,just binding slightly, no other air thru slide valve or vacuum leak), only fuel is from the FI pump plungers(none from CSV, etc.)
Goal: minimum fuel flow to get 800 rpm with the proper air flow to support 800 rpm.

1. Remove control rods from butterfly and FI pump. This removes any control rod linkage errors from idle adjustment.
2. Start engine and adjust idle air to get maximum rpm. Note rpms.
3. Stop engine. If rpms are greater than 800, push in and turn FI pump fuel adjustment disc(on back of FI pump) CCW two clicks(less fuel). If the rpms are less than 800, turn CW two clicks(more fuel).
4. Repeat 2 and 3 until engine idles at 800 rpm. Stop engine when adjusting FI pump. One click near the 800 goal.
5. With engine at 800 rpm, close idle air screw to reach 750 rpm. This give a 50 rpm rich setting.

Re-attach control rods to butterfly and FI pump. If this changes rpm, fix the linkage.

Happy Motoring!!

jameshoward · « **Reply #8 on:** October 31, 2007, 01:35:27 »

Further to the posts by Peter and Matt, I did this job last week AGAIN (for about the forth time in as many months) in a last ditch effort to sort out my idle problem before resorting to pulling the FI pump once more. I used the Wiki post mentioned by Peter and the linkage post from Matt - this is the first time I've done it step by step using those posts. Low and behold, my rough idle problem is now cured. It transpired that the butterfly was not closing properly due to some grime around the housing. I removed the fitting that warms up the air on the front of the throttle and used a degreasing spray to clean the butterfly. I also cleaned out the vacuum retard hoses/line as best I could. I replaced the ball joints on the linkage rods and adjusted the little pot (forgotten the name) onto which the linkage rests when ones goot is removed frmo the pedal. Bottom line is that the idle can now be adjusted properly using the warm idle air screw. I've done this several times before but only once using the post. It was well worth it, so stick with it and read up as much as you can using the search. There are some real nuggets in other posts that helped (like cleaning the butterfly).

JH

230slhouston · « **Reply #9 on:** October 31, 2007, 22:02:59 »

I tinkered with my car this afternoon for 10 minutes. The linkage fromm the IP to the shaft that runs across the tappet cover seemed to short. I removed the linkages, set the enrichment screw on the IP turning it five clicks, cutting back the adjustment screw on the intake. The engine now idles at 800-900RPM. I adjusted the linkages the idle is now fine.

This was just a test, I have not as yet accurately set the dwell or timing with any equipment. Will do it this weekend and then set the idle properly.

The car starts immediately when cranked.

This is truly a very resourceful forum. I appreciate all the help and advice.

Thanks
MBP

jameshoward · « **Reply #10 on:** November 01, 2007, 02:08:46 »

Follow the post linked below by James and Peter. The IP linkage should be flat against its stop at idle and the butterfly should be closed. Adjust to that. I did dwell and timing first before the linkage. I put new points on beforehand as they cost next to nothing and I was fed up with chasing the problem. You might want to do the same. Check the air filter on the FI pump also to make sure it's clear; you could also check the FI pump oil level using the dipstick under the solonoid a the back of the pump whilst you're at it - if you have the original R11 FI pump on your 230. I don't think it will affect your idle but since you're there...

hands_aus · « **Reply #11 on:** November 01, 2007, 06:11:21 »

quote:
Originally posted by jameshoward

also check the FI pump oil level using the dipstick under the solonoid a the back of the pump whilst you're at it - if you have the original R11 FI pump on your 230. I don't think it will affect your idle but since you're there...

If the oil level is too high the counterweights of the injection pump will spin in oil and you will never achieve the correct mixture.

Bob Smith (Brisbane,Australia)
RHD,1967 early 250 SL, auto

jameshoward · « **Reply #12 on:** November 01, 2007, 06:52:35 »

Bob,

Thanks. I know you're a bit of a guru on this subject as I read a lot of your posts when tackling my FI pump that pi$$ed oil all over the floor when I went to check the oil level. You point here would probably explain why my MPG was so bad before I had the pump seen to.

JH

hands_aus · « **Reply #13 on:** November 02, 2007, 04:51:55 »

quote:
Originally posted by jameshoward

Bob,

Thanks. I know you're a bit of a guru on this subject as I read a lot of your posts when tackling my FI pump that pi$$ed oil all over the floor when I went to check the oil level. You point here would probably explain why my MPG was so bad before I had the pump seen to.

JH

Hey James,
guru? me?
LOL

I went through the process of adjusting renewing cleaning the components of my FI and ignition systems under the generous, patient guidance of Joe Alexander.
I am happy to be able to pass on my limited knowledge and hope someone else can achieve the best outcome.

regards from Oz

Bob Smith (Brisbane,Australia)
RHD,1967 early 250 SL, auto

J. Huber · « **Reply #14 on:** November 20, 2007, 15:49:11 »

Ok New development... I have been laid up waiting to have my water pump changed. Dec. 4/ all parts are here. In the meantime, I saw no problem with warming up the car (topped off coolant) and doing some other maintenance. I changed oil & filter -- then today, I did the main fuel filter and O-ring seal. Then...started up the car -- ran a little rough for a minute -- then idled as normal...but then it stumbled and died. Restarted -- same exact thing. Idles fine for 20 seconds then stumbles to death. And again and again. I messed with air - and even gave myself a click or two richer but same thing. Is this an idle thing or is it related to fuel filter change? or even water pump problem? Its new and annoying, I know that much.

James
63 230SL

merrill · « **Reply #15 on:** November 20, 2007, 17:46:56 »

did you check the fuel pressure ?

my car would idle fine then die, I just sent my fuel pump to hans at H&R to inspect and rebuild.

Hans had already rebuilt the inj pump and checked the injectors.
after checking just about everything else we decided it has to be the inj pump.

Matt
Austin Tx
66 230 sl - "white"
78 300 D - Blue
98 C230

ja17 · « **Reply #16 on:** November 20, 2007, 20:23:26 »

Hello James,

I agree with Matt, a fuel pressure reading may may provide a clue. At least you will be able to rule some things out if the reading is ok.

Joe Alexander
Blacklick, Ohio

J. Huber · « **Reply #17 on:** November 20, 2007, 21:21:48 »

Thanks guys. I actually thought about that too. I decided to test things again. I let the car sit for an hour or so -- then tried things again. This time, it started up as normal -- and idled about normal for a good 5-7 mins. I was waiting for the temp to get to warmed up. I shut it off, restarted and this time it idled kind of normal -- but had some fluctuation lower. Did not die though. I put it in gear and out and it stayed in the 750-900 range...

Is it possible that after the new fuel filter, it had the hiccups?

James
63 230SL

merrill · « **Reply #18 on:** November 21, 2007, 11:32:48 »

Well I Heard back from HAns at H&R and boy do I feel stupid,

when he took my pump apart the intake screen was clogged, he cleaned the screen and according to him the pump works great.

It may be time for all of us to do some maintenance and check all our fuel system screens.

matt

Matt
Austin Tx
66 230 sl - "white"
78 300 D - Blue
98 C230

Paddy_Crow · « **Reply #19 on:** November 21, 2007, 11:37:40 »

quote:
Originally posted by J. Huber

Thanks guys. I actually thought about that too. I decided to test things again. I let the car sit for an hour or so -- then tried things again. This time, it started up as normal -- and idled about normal for a good 5-7 mins. I was waiting for the temp to get to warmed up. I shut it off, restarted and this time it idled kind of normal -- but had some fluctuation lower. Did not die though. I put it in gear and out and it stayed in the 750-900 range...

Is it possible that after the new fuel filter, it had the hiccups?

James
63 230SL

It's possible that when you changed the filter, you got some air in the lines which took some time to purge.

Democracy is two wolves and a lamb voting on what to have for lunch...

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Author Topic: Engine Idle adjustment (Read 16234 times)

230slhouston

230slhouston

glennard

230slhouston

Paddy_Crow