Hi,

I have owned my 300ce for 7 years and like all owners have had to deal with problems from time to time. However now I am facing a problem that I and my Mercedes mechanic are struggling to resolve.

Back in 2005 my car began to have issues starting when hot, this was resolved by giving the car a bit of throttle when starting. In 2009 I moved to a new area and took my car to a dealership for a service. Following this service the car started stalling from time to time when traveling at low speeds or when coming to a stop. The dealership took no responsibility for the issue and after some pretty poor treatment I vowed never to take a car to them ever again.

I now have a good independent helping me to resolve my problem but we are running out of ideas and I could do with some advice. The symptoms, when the car is warm and sometimes when it is cold the car will start very briefly but then cut out. If I start it using some throttle the car will start but often stalls again when I take the throttle off. When coming to a stop or traveling at slow speeds the car will stall without warning and I have trouble restarting it and have to use both feet to keep the throttle up whilst being on the brake. Sometimes this will happen pretty regularly during a journey and other times it may happen once or not at all.

So far the fuel system has been checked and I have been told that it is ok. They found that the fuel relay was clicking a lot and was very worn, this was replaced but didn't solve the issue. When this part was replaced the engine was given a very good clean in terms of air intakes, throttle bodies, etc. Next to be replaced was the top center sensor to no avail, and last week the crank shaft sensor was also replaced. Again to no avail.

I am taking the car in again next week to be hooked up to try and find if there is an electrical issue causing the problem, however I'm hoping to get some advice from the board to aid in cutting down the possibilities.

Can anybody help? Please...

__________________
Want: CL500, 1997, has to be black!

1990 300CE
Black exterior, Cream Leather, 149k
1988 300E
Gold exterior, Beige cloth, unknown miles , sold
1998 S500L
Black exterior, Cream Leather, 41k, sold

In the USA the 1990-92 300CE's used a M104 engine (24 Valve), does your version have a M104 OR is it a M103 version?

Either way, has the distributor cap & rotor been replaced? as well as the spark plug wires?

__________________
MERCEDES Benz Master Guild Technician (6 TIMES)
ASE Master Technician
Mercedes Benz Star Technician (2 times)
44 years foreign automotive repair
27 Years M.B. Shop foreman (dealer)
MB technical information Specialist (15 years)
190E 2.3 16V ITS SCCA race car (sold)
1986 190E 2.3 16V 2.5 (sold)
Retired Moderator

This sounds like an M103 but, either way, I agree with MBDoc.

If you're going to keep the car, ensure you have the entire HT system up to scratch:

Plugs, Distributor cap and rotor, HT leads.

Go to MB, ask for discount and get the HT stuff from them. I have and all my hot problems have gone (in fact, I have Beru Silicon HT leads and these seem fine).

Also check any temperature sensors. If you've got the M104, check the air intake temperature sensor - €12 from MB.

Once the HT is in fine fettle, take it from there - these engines demand the best HT components.

RayH

Thanks for the input guys. Mine is the 12 valve M103 engine, sorry I didn't mention that. Plugs have been changed recently and the rotor was changed a few years ago. Not sure about the HT leads and distributor cap, will have to check my receipts. I'll also look into the temperature sensors.

In terms of the ignition system is there much evidence of issues with the ignition coil?

__________________
Want: CL500, 1997, has to be black!

1990 300CE
Black exterior, Cream Leather, 149k
1988 300E
Gold exterior, Beige cloth, unknown miles , sold
1998 S500L
Black exterior, Cream Leather, 41k, sold

I've had no problem with ignition coils over nearly 35 years and a range of MBs. I do have a spare for my 300CE-24; I tried it and it made no difference.

Regarding ignition parts in general, I have learnt the hard way not to buy anything but the best. My cheap Bremi cap and rotor lasted less than 2 years so I've now got MB replacements. More expensive? Yes, but these parts live in a very hostile environment so you need quality.

I know it's easy to spend other people's money but I have just sunk over €500 in MB ignition parts and I intend to forget about them for the next 15 years by which time I will have forgotten the €500 too.

When my new Bremi cap failed, I replaced it with the original, 19-year-old MB part and that worked fine until I coughed up the €200 for the new one.

Touch wood, the car's now going fine, even to the extent of starting first time with no foot on the pedal when it's very, very hot.

Sorry to harp on and bonne chance.

RayH

Not "resolved," just jury-rigged.

Engine is flooded due to leaking injectors.

Needs new injectors.

May prove futile trying to "work around" leaking injectors, as there's really no adjustment for it.

__________________
Kent Christensen
Albuquerque
'07 GL320CDI, '10 CL550. '01 Porsche Boxster
Two BMW motorcycles

Several others that I know have had the same problem as you. The resolve was to replace the crankshaft position sensor. It is located on the top side of the bell housing and can be viewed from above. Look downwards between the oil filter and head.

Good Luck,

Jayare

Jayare, I just had the crank position sensor changed and that didn't make a difference, but thanks for the suggestion.

Ikchris, previously I raised the issue of leaking injectors with the mechanic and he assured me that they are okay. I'll raise this again with him when the car goes back in on Monday.

The car is being hooked up on Monday to check the electronics and I will raise the ignition system suggestions with them. I will also discuss the temperature sensors with them so they can check these as well.

Are there also some vacuum hoses that make up the ignition system?

Thanks again for the input.

__________________
Want: CL500, 1997, has to be black!

1990 300CE
Black exterior, Cream Leather, 149k
1988 300E
Gold exterior, Beige cloth, unknown miles , sold
1998 S500L
Black exterior, Cream Leather, 41k, sold

After throwing thousands of dollars at my daughters car, we learned that most every time it started running funny like yours, it was the oxygen sensor. Always change that sensor first then go from there. They don't last long and don't show up as a light. You are welcome in advance.

Well my car is finally fixed. It worked out the it was the idle slide causing issues. It was getting stuck and hence the car was stalling out. The part has been replaced now and things are back to normal....... However....... I now have an interesting new problem that just started where the car now struggles to turn over when starting and when it starts the indicators give a single blink!

Very strange, time to get back onto my mechanic to see if it's related to the work that was done!

__________________
Want: CL500, 1997, has to be black!

1990 300CE
Black exterior, Cream Leather, 149k
1988 300E
Gold exterior, Beige cloth, unknown miles , sold
1998 S500L
Black exterior, Cream Leather, 41k, sold

For the benefit of those of us who don't know that term, what is an "idle slide?" Is this part of the idle air control valve or the idle microswitch or the throttle valve switch? A part number if you know it would clarify. Thanks. Glad your gremlin is fixed.

__________________
1988 California version 260E (W124)
Anthracite Grey/Palomino
Owned since new and still going strong and smooth
MBCA member

Past Mercedes-Benz:
1986 190E Baby Benz
1967 230 Inherited from mom when she downsized
1959 220S Introduced me to the joys of keepin' 'em goin'

There are only 10 kinds of people in the world--those who understand binary and those who don't

It's the idle control valve, also known as the auxiliary air slide.

__________________
Want: CL500, 1997, has to be black!

1990 300CE
Black exterior, Cream Leather, 149k
1988 300E
Gold exterior, Beige cloth, unknown miles , sold
1998 S500L
Black exterior, Cream Leather, 41k, sold