1992 300E 3.0 L stalls when warm

[aermotor]

My 1992 300e 3.0L starts fine, runs very smoothly and well - it would run at road speed all day long. But once up to operating temperature, if I stop at a light or whatever, letting it idle, it stalls and won't start at all again until the engine has cooled off. Then it starts.

When it won't start, it has spark, so I don't think it's an ignition module. The fuel pump runs then shuts off when keyed, so I think the MAP relay is fine. I replaced the crankshaft position sensor - problem not solved. Changed out the 4 pin water temperature sensor that controls fuel and spark at the computer - problem not solved.

How to I check the engine for fault codes?? Is there a place I can plug in a code reader?

Any ideas?

Thanks!

Dave

[BigRed0803]

I would check the rotor button and distributor cap common issue with that motor. Visual inspection would let you know their condition.

[aermotor]

Thanks - I'll check that out tomorrow night. Hope that's it.

Dave

[gabzor]

don't forget to check your plugs/wires.. i mean plugs arn't even that expensive but make sure you get the oem brass ones..

i had a friend with an e420, he had simillar symptoms all he needed was a tuneup

[rayhennig]

Originally Posted by aermotor

it stalls and won't start at all again until the engine has cooled off. Then it starts.

Any ideas?

Thanks!

Dave

Have you changed the distributor rotor? If it's old or a cheap replacement, get the best you can - MB - and try it.

Same symptoms for me and even the original, 17 year old rotor solved it.

RayH

[Benz Mondi]

Had the same issue and found out it was the crank position sensor. It's an easy fix. You likely have the original one on the car. Good luck.

Al

[stormyc88]

I had the same problem 4 years ago. Fuel pump relay. Easy and not very expensive.

[aermotor]

The first thing I checked out was the fuel pump relay. I ordered a replacement, but my car is fitted with a MAS relay instead, so it wouldn't fit. Instead I turned on the key and listened for pump activity with the door open - I could hear the pump spool up and then shut down when up to pressure, but still, when it was warm, it wouldn't start. So, I re-checked for pump sound and it's there, so I made the assumption the relay is ok.

Then I replaced the crankshaft position sensor, and still the same problem persists.

Then I replaced the 4 pin temperature sensor that sends engine temperature information to the ecu. Still the same problem.

I have yet to check out the rotor and cap as suggested, since I think they are the originals. In the meantime, does anyone know if there is a way to read trouble codes (fault codes) on this vehicle??

Thank you all for your time and good advice!

Dave

[rayhennig]

Originally Posted by aermotor

I have yet to check out the rotor and cap as suggested, since I think they are the originals.

Need I say more?

RayH