A not funny problem............. - PeachParts Mercedes-Benz Forum

#1 01-09-2003, 10:08 AM

OK guys , problem with a 1987 300E, UK model.
Engine die's in the following circumstances,
At a steady cruise or normal freeway type driving , but if throttle
position is held , engine will pick up again after a few seconds.

City type stop start or slow-fast-slow driving , engine die's or will not pick-up when getting back on the throttle. Then when a re-start is attempted engine does not want to restart but does eventually after much cranking. Sometimes it is a clean re-start , sometimes missing and rough.

Otherwise the car drives perfect , that is, until the fault occurs the engine runs fine without missing or lack of power.

Just wanted to find out if some1 had a "I know what that is " cure before I go for a diagnostic.

I have checked battery cables , and I replaced the distributor cap as it needed doing anyway. Have checked for obvious loose connections etc.

Any suggestions would be welcome.

zeb · #2 01-09-2003, 11:13 AM

have you tried the fuel pump?? or maybe the fuel filter??
Sounds like it may be strugglin for fuel

#3 01-09-2003, 01:11 PM

evoboy,

They say that misery loves company, so I suppose you will be somehow comforted to know that I have been fighting the same problem for several months.

You can read most of my responses by doing a search for a thread called "Bosch KE Problem" in this forum.

Steve Brotherton who troubleshoots these cars all day long indicated it might be secondary ignition problems. I replaced rotor and cap and it ran fine for about a month until a damp day came along and it started again.

I have since replaced the coil and it ran fine for about 60 miles this morning then started the same thing again.

In my case when it acts up it won't make power until the throttle reaches the floor THEN it takes off under full power.

Let's help each other by staying in contact with each other while we work through this problem.

I really don't think it has to do with the fuel pump, because when the throttle reaches the floor it gets full power INSTANTLY. If it was a fuel pressure problem, the pressure would not be capable of building instantly.

Have a great day,

#4 01-09-2003, 01:13 PM

Hi Zeb,
Cheers for the reply.

I had thought about the fuel pump , but this is an intermittent problem so my inclinations were to a sensor or relay etc , but where to look ??

#5 01-09-2003, 01:17 PM

Well, now that I reread your post, I think our problems are different. On mine, when the throttle hits the floor the power almost always comes on instantly.

We can still compare and share notes.

Good luck,

#6 01-09-2003, 01:24 PM

Larry,
Oh no , sounds like your struggling with the same gremlin

I'll relay my progress and hopefully one of us will find the solution.
Have you had a diagnostic ?
It's interesting you mentioned damp weather , it does seem that the problem occurs more so in damp or wet , although it is cold and icy here today and the problem was quite bad.
I notice your car has stellar mileage compared to my mere youngster at only 133k

Really though , there is nothing like a Merc

L8r

Gary

TCCBass · #7 01-09-2003, 02:11 PM

Larry, sorry to hear your 300E is having issues still. Mine is at the mechanic's shop AGAIN! I replaced the check valves in the fuel pumps, adjusted the Lambda again, put a new adjustment screw on, etc. Still...it runs good on the highway but doens't like to start in the morning or sit at stop lights. My mechanic has a complete used fuel distributor unit he is installing to see if that makes any difference. We have tested and tested...can't find anything wrong. I am to the point that I'm hoping a tree will fall on it, but alas, Dallas doesn't have that many trees.

I will let you know what he finds...maybe it will shed some light.

TCCBass · #8 01-09-2003, 06:55 PM

Update...

Mechanic called. He unbolted the pipe between the engine and the catalytic converter. The engine runs beautifully. So, I guess it's the converter.

Is there any chance that a muffler can be bad and cause that much restriction? I know it has had more exhaust noise, but I've never heard of a muffler causing that much restriction.

Any advise? I checked online...cheapest converter I could find for the 92 was $400. Guess I'll order one tomorrow...

zeb · #9 01-09-2003, 09:38 PM

Don't bother just leave it out!!

get more power!!

Piotr · #10 01-09-2003, 10:07 PM

check around! you should get an aftermarket one for $200

TCCBass · #11 01-10-2003, 10:41 AM

I'm going to call some muffler shops today and see. All the pictures I've seen have the long tube from the motor. It's a big piece...so I'm pretty sure a universal converter won't fit correctly.

If anyone has a source...I'm all eyes...

Potomac Pat · #12 01-10-2003, 01:44 PM

After reading this thread & all the posts and comparing it to the problems that Larry is having, I think I am experiencing the same issue.

I have changed out more components than necessary I'm sure. I have changed every components of the fuel delivery package. I mean everything from the sending unit on forward. The fuel distributor & EHA are new, injectors, cold start valve, idler air lines, airflow meter, throttle plate (body below airflow meter), Fuel pump realy, KE control, etc..........

I also traced over every bit of the ignition system and R & R'd everything there as well. Crank sensor, wires, distributor, distributor cap & rotor, coil, BOSCH H6 plugs, EZL. I also traced out the vacuum lines and replace any & all pieces that I even suspected may be causing an issue.

I also replaced the three sensors on the front of the head.

After struggling for more than I care to mention, I guess I am going to break down & buy a new wire harness. My problem is no doubt electrical & this is the last thing I can think of to swap out.