MB w124 1986, dies on idle

[AnuDa]

I did remove the airfilter box and I found the IACV. The issue is that I don't know how to take out the IACV. I tried to understand how it is installed there. However, in the end it didn't work out. I had no idea how to take it out. I took picture of it. I'll upload them here if you had issues finding them in the MEGA link.

 

[optimusprime]

So if you are unable to remove it you can try this ..On the one end will be a power plug remove it if you can .Then start the car and report back how it runs .

 

[AnuDa]

I unplugged the power to the IACV and started the car. The car started but almost instantly died from choking sounds. What happens more specifically is that the car tries to hold on but dies after two tries; it almost dies, but comes back to life for less than a second , which happens twice then dies. If you want I can record a video on what happens?

 

[optimusprime]

Anu the operation you have just done, should make the car rev up to much above 1200 revs . Have you checked for bad vacuum leaks ? you must have one some place .

 

[optimusprime]

Anu the operation you have just done, should make the car rev up to much above 1200 revs . Have you checked for bad vacuum leaks ? you must have one some place .

See this --

 

[AnuDa]

Good day!

I haven't checked for vacuum leaks, I don't know how one do that. I am very sure there's a lot of leak. There's many bad hoses and probably many screws that needs to be replaced or be screwed down.
Any ideas how and where to start, or perhaps better I take it to a mechanic?

 

[optimusprime]

Thes W124 use vacuum on so many parts,, the vacuum system condition must be 100% leak proof .So first step is to stop any vacuum escaping, You need a vacuum testing gauge .. Or a large cigar and remove a vacuum hose and blow the smake down the pipe or hose ,. now look for the smoke..

 

[optimusprime]

Good luck .

 

[grober]

I feel that a different, more prudent mechanic is your starting point.

If, as I think, he has played with the mixture control (3mm allen key), without knowing what he's doing, he is not the man for the job. Do you see lots of 80s/early 90s Mercedes at his place?

And if he's used the mixture control to increase the idle speed, I fear he's guessing. The idle speed is automatically set.

And jet washing under the bonnet is a risky business as you can damage electronics (few on this car) and get water into the air filter and elsewhere.

I think you need to dry out everything and do a service of the HT system, air filter and general clean up. Then get the mixture control set by someone who knows these older cars - gas analyser/duty cycle checks - not sure on your car..

Sorry to be of not much help.

Good luck from damp, cold France.

RayH

you are right the allen key adjustment is extremely delicate-its literally a 'tweak'---really needs an exhaust gas analyser to set the mixture strength. There is also a 'throttle closed' electrical switch which signals the control unit that the engine is idling. If this has been damaged by the jet wash then the car may not idle

 

[optimusprime]

The adjustment with the injection metering unit was done to mask some other problem.,like vacuum leaks AnuDa has .

 

[grober]

http://berlinasportivo.com/Technical/lancia/Thema832/Bosch-KE-Jetronic-OCR.pdf

 

[AnuDa]

Hello guys! Thank you for your replies!

I just went down to the car to put back the air filter box, but I felt defeated. I went to check if I couldn't take out the IACV. I was careful in the beginning. But this time I had, so I added more effort to take it out. It wasn't screwed on at all. It was only the plastic thing around it that kept it in place, aside from the hoses. I found that one of the hoses was entirely bad. I have no idea if this hose can be repaired. I've taken pictures for you, it is in the same MEGA link I've sent earlier. Please take a look at the IACV and give me your assessment and guidance.
@optimusprime I will try to make a vacuum test for leaks, after I am done cleaning the IACV and repairing the hose, if possible.
@grober I will also try to take out the throttle valve switch if possible and see how I can troubleshoot it at home, with your guidance of course.

In case any of you don't like to use my MEGA link then let me know and I'll attach the pictures in my next message.

thank you in advance!

 

[AnuDa]

Can I use this to clean the IACV? I don’t have carb cleaner atm.

 

[AnuDa]

I was checking the IACV and found a gum plug inside the hose inside the IACV, there’s a picture on it in the IACV folder in MEGA link. Is that plug supposed to be there?
What about that plastic thing that is screwed on to the IACV?

 

[AnuDa]

I've added the link here, check the attachment.
Should be much easier to reach for the folder that way. Sorry for not thought of that earlier.

 

[AnuDa]

@everyone
I am considering to use shrink tubes to repair the hose, I am not sure if it is a good thing, due to the shrink melting temperature of the item. Is there a risk to use a shrink tube on a hose connected to IACV?

 

[AnuDa]

I found a hose that looked almost similar to the one I have, except for that it doesn't have three ends, it have two.
I guess I can't use the one I found online. I can't really find one that is similar to mine. In Autodoc it says that it should fit my car. But I can't say that it does since it has only two ends.

 

[AnuDa]

@everyone
I’ve uploaded a picture of how I repaired the IACV hose with a shrink tube. Please check it out and make an assessment whether I should use it or not. The picture is in my MEGA link inside the IACV folder.

I’ve also bought cleaning spray for the IACV. I’ve drained it with it and been shaking it a lot. I’ve drained it several times. It is filled now and will leave it for tomorrow. I’ll try to put it back together tomorrow and try it out and will update you with the results. Unless you advise me not to use the hose with a shrinked tube on.

Thank you in advance!

 

[AnuDa]

Can anyone explain what that rubber plug is for that was inside the IACV together with the hose?
I'd appreciate a quick reply so I know if I should replace it back or if it shouldn't be there.

 

[AnuDa]

UPDATE!

I was eager and couldn't wait for a reply. I went down to the car and connected the IACV, IACV hose (without the rubber plug) and the filter box. The idle stalling is NO MORE!! However, now it REVS UP above 10.000 and CONTINUES TO REV UP every couple of seconds on idle. Could it be because I didn't put back the RUBBER PLUG or something else?
I'll go down again and try change back the fuel mixture adjustment to where it was before the mechanic increased the mixture.