My 300SE problem - update
 

Last week I posted a message about my 300SE that cut out and refused to start again. We charged the battery and it started, but everytime I engaged a gear, it would cut out again.

I got the car towed to a local garage. I went to pick the car up today and they said that they checked the fuel pump and it was ok. They had the injectors out and they were spraying fuel, and there was a spark from the plugs.

After they put it all back together again, it started fine and there has been no problems since.

Although when I stop at traffic lights I can feel the car shaking slightly as if it is going to stall.

Could this still be the fuel pump relay, even though the actual pump is OK?

I'm going to take it to my Mercedes tech later this week, unfortunately I couldn't get it towed to him at the time of the breakdown.

Thanks for the help,

Mine had a long time shaking at the stop lights as it was about to stall. It turned out that it needed new fuel injectors. Problem was solved after that. However, mine was a long time problem, yours sounds much more sudden so it may be different. I assume you have a manual gearbox.

This is actually a problem that's been going on for over a year. It's also an auto box!

Maybe I need new injectors!!

this is my reaction to reading about the traffic light "shakes"
because of a similar rough idle on my 300SE - I started a long journey..
Gradually replacing the OVP , fuel filter & pump, spark plugs & wires. Then the Distributer cap & rotor. I Changed out the motor mounts and cleaned the Idle control valve(replaced both hoses on it). The rough idle was almost gone.
Finally a couple weeks ago I got around to replacing the injectors and hoped that was going to be it. I had the mixture adjusted at the shop and drove away feeling real good. ...
TWO WEEKS and I can feel that familiar shake (just a bit) skip & hesitation returning - when coming to a stop...and the mixture is quite rich I think, because when pressing on the Air Flow Sensor Plate the car dies instantly and gas milage is down. The Inside of the above was moist (leaking distributer ? ) to the touch.
Maybe this info can assist you in your quest to cure the shake...and hopefully someone else might have advice for me too.

Consider the following article:

http://www.babcox.com/editorial/ic/ic49954.htm

While it addresses EFI which 300SE/300SELs are not, I suspect there's a fair amount of cross-over here.

Check out what it has to say about rich running.

Hi Mike,
I looked at the article but (since I replaced both fuel pump & Filter recently) feel my problem is of a different nature.
The rough Idle is intermitent, and most noticable as the car slowes to a stop.
My thinking, based on searching the forum and talking to a bunch of people, is that my rough Idle is more likely from a leaky ditributer, the airflow meter body or a EHA valve .
All these cost a nunch to replace - so I am holding off until I can figure this out.

Have you considered the fuel distributor. In the SEs, it may be a common problem that beneath the fuel distributor you have worn rubber seals that permit fuel (gas and sometimes fuel) to be leaking out. You would notice an aroma of fuel entering your cabin. If so, your cars stalls. I would recommend getting your tech to remove the air filter and look closely at the fuel distributor for any signs of stress and leaks with all the rubber seals holding it in place.

Hi ymsin

I don't know about Oliverp's SE, but mine does not stall nor is there a visible leak around the distributor - or for that matter any odor in the car. So it is still unclear(in other words,I don't have a clue..)

gidpor - I was commenting on Oliver's post. Anyway, if its erratic idle at stops, the first thing to look for would be the air-fuel mixture - basic tuning. Then we look at the plugs and injectors before going on to the idle valve control. Sometimes we ave new plugs and injectors and just-tuned engines, yet the idle runs up and down a little. This could also be caused by dirt going into the idle valve and in which case, giving it a clean might just solve the matter. If having cleaned, and in extreme cases, replaced the idle valve and yet the problem persists, it could also be the OVP.

btw - whats the degree of play on your rpm?

I had a similar problem on my 92 300 se and my best recollection is that an electrical module was replaced. That car has about 35 computors/modules in it and is generally loaded with electrical gremlins. I finally got rid of it after $17,000 of warranty work within the two years that I had it. Good Luck!

What do you drive now ?
 

I was wondering what car replaced the SE.....

Actually a mechanic I know suggested replacing the EHA Valve, which is a module of sorts.
I was trying to learn the situation and see how (If ?) people could tell between a EHA malfunction, a bad distributor or a nasty Idle valve ( I did clean mine a couple months ago)

Gidpor

I now drive a 99 Cad. Escalade and love it! However, my daily driver is a 82 240D! I'am still a Benz enthusiast at heart, but darn, those newer models are sapping my passion.

If you're interested in learning about the inner workings of your Bosch FI system, check this out. Good Book.

http://www.amazon.com/exec/obidos/ASIN/0837603005/ref=pd_sim_books/103-7744839-1002200

If it's as current as the one I have, it doesn't cover KE3 and KE5 as found on later M103s. I know my 91 SE has KE5. I don't know what the differences are. Great book nonetheless.

Sixto
91 300SE
81 300SD

It was printed in 1990, so it will probably cover my car - 1987-300SE/Euro . Sounds like a good investment.
Would you know if there is a difference between US cars and European FI systems ?
If so , does the book cover the Euro..?