C124 Stalling problem

[D. O'Brien]

Hi there,

My 1990 C124 has developed an intermittent stalling problem when driving. I have read many articles about this issue and it seems there endless possibilities in relation to this fault; OVP, vacuum leaks,crankshaft sensor, fuel pump relay, fuel tank breather, EHA valve, etc.

Can anyone in Mercedes land save me further heartache and expense by pointing me in the direction of the most likely culprit?

Any assistance much appreciated.

 

[optimusprime]

Check fuses see pic And clean the ends put a dab of vasaline on the end caps, not to much . Also clean and grease all earth points .Check small bore pipes for splits on rubber joints. These are general jobs first.

 

[brucemillar]

Good advice here. Give the fuse box a really good clean. It may be worth replacing the fuses with brass type ones. As Optimus says a dab of grease on the ends is good.

Sent from my iPhone using MBClub UK

 

[optimusprime]

You can try this .If no one can find the problem it may be this ..
Remove the connector from the rear of tachometer if it eliminates it replace tachometer.
TD terminal of tach as intermitant short circuit .So then the fuel pump is not activated.Giving stop start and stall .

 

[darreningram]

I had similar problem in 300CE- kept stalling randomly and I had to jump out and wriggle the fuel relay- good times! Local specialist- creevys- took relay apart and soldered it and no problems after that. See Haynes for fuel relay position- maybe try cleaning first

 

[WDB124066]

Rough idle & eventually stalling while standing still could also be MAF related, see if you can swap it out temporarily for a known good one...

 

[bolide]

It'd probably best if you tell us what engine & gearbox the car has and whether it's a UK car. And whether the car stalls when you pull away or it dies whilst being driven

I am guessing it's a pre-facelift car with the old 8-valve M102 engine. If so it won't have a MAF but it'll have the old-style injection with a distributor, coil and an ignition pack on the inner wing

There was more than one type of ignition system use with the 4-cylinder engines but I don't know which types were used when. If you give us a VIN and an engine code we won't be guessing any more

Nick Froome

 

[dinoy]

ovp has red fuse check it is not burned

 

[EuroCarParts]

Hello D. O'Brien

I am sorry to hear that you 1990 C124 has stalling problems . Matters is even worse since there are soo many possibilities that this problem could be blamed on. I really feel your pain.

I can't help you on this problem because I am new to the car parts industry [Almost like you]. Lol

I work for Euro car parts on the web team ironically.

However, weeks ago I was working in an organisation that was in another dimension from the one I'm in now.

I am really eager to learn about cars from everyone in this forum.

Hopefully, one day we could all come down to euro car parts and discuss how we can help everyone in this group

Apologies about the long winded message.

I Hope you eventually detect the problem.



Seyi

 

[ray_hennig]

Hi there,

My 1990 C124 has developed an intermittent stalling problem when driving. I have read many articles about this issue and it seems there endless possibilities in relation to this fault; OVP, vacuum leaks,crankshaft sensor, fuel pump relay, fuel tank breather, EHA valve, etc.

Can anyone in Mercedes land save me further heartache and expense by pointing me in the direction of the most likely culprit?

Any assistance much appreciated.

A methodical approach is vital here and a pre-requisite is good electrics. A new OVP ensures that clean, regular power is supplied to the electronics. Do NOT get cheapo parts for these cars, EVER.

So, start with an MB (or possibly KAE/Kaehler?) OVP.

Then ensure that all HT components are 100%: distributor cap, rotor, leads and non-resistor, copper-core plugs. MB/Beru/Bosch and also NKG for plugs.

Eliminate vacuum leaks.

Check that fuel delivery duty cycle is around 50% closed loop - Google this if in doubt and learn how this works.

A clean, new fuel filter is important.

Regarding electrics, invest in a spray can of good quality electrical contact cleaner. As has been suggested, remove and clean all fuses using the contact cleaner and not vaseline or any general purpose grease.

Every time you see a plug/socket or other connector to anything, unplug it carefully and clean thoroughly with contact cleaner.

As said, a methodical approach and patience is the answer and do not dive in an replace hugely expensive electronic modules until they are proven (by replacement from donor?) faulty.

It's not clear to me which engine you have (12v or 24v), however, the technology will be similar to my 24v and all the above equally relevant whichever you have.

The only cheap parts worth buying for these cars are used ones.

Can't think of anything else.

Oh, did I mention cleaning all electrical contacts? Do them and do them well.

Bon courage.

RayH
PS: I say all this because I had the stalling issue when I first bought the car from MB. They replaced the entire fuel metering unit under warranty and that did nothing. My background is electronics so I dived in and the thing still starts and doesn't stall after 1/4 million miles.

PPS: I'm lying slightly. Sometimes, when coming to a standstill and selecting Neutral or Park, it will hunt and stall. If I select Reverse, no problem. My theory is vacuum leaks and I'll get round to removing the metering head some time and replacing all the pipes and intake seal.

 

[D. O'Brien]

Wow - overwhelmed with all the helpful responses. Thank you very much everyone.