Parts Catalog Accessories Catalog How To Articles Tech Forums
Call Pelican Parts at 888-280-7799
Shopping Cart Cart | Project List | Order Status | Help

Go Back   PeachParts Mercedes-Benz Forum > Mercedes-Benz Tech Information and Support > Tech Help

LinkBack Thread Tools Display Modes
Old 08-30-2000, 07:58 AM
Posts: n/a

I've a '90 300se. Recently when I stop the car the engine shudders a bit and then dies. The RPM meter toggles for a while and the engine shakes before it dies. While driving the car is ok. I have resorted to leaving my foot on the accelerator pedal slightly when the car is stationary. My mechanic initially changed the fuel pump and filter but this did not solve the problem. He tells me now that the "fuel seperator" needs to be changed. What is this and do you happen to know how much it would cost?

Thanks a lot.

Reply With Quote
Old 08-30-2000, 09:22 AM
Join Date: Mar 2000
Location: Gainesville FL
Posts: 6,844
Actually, I don't know what he is talking about. The evaporative emission systems have a vapor separator designed into the tank on most cars. They used to be separate.

I read a lot of posts asking questions, where previous parts were installed. It seems that there must be a lot of trial and error testing going on. It would be my position that any part being installed would solve some specific test deficiency. This is proper testing. If you think a fuel pump is failing at idle (the most unlikeliest senario I can think of) it would more likely be electrical (relay etc).

The hypothesis should be backed by fuel pressure test readings which then are verified upon replacement. Believe me, whatever is occuring has a result that can be measured by more than the seat of your pants (the seat of your pants said the car died).

I personally would go for an OVP relay if I was shot-gunning parts. The test that would prove it would start with measuring the current through the idle control motor. Low idle that stalls the car will get readings below 500ma with 600+ being appropriate. The OVP relay causes the low idle by providing a weak circuit that reduces the current even with the controller trying its hardest.

Steve Brotherton
Owner 24 bay BSC
Bosch Master, ASE master L1
26 years MB technician
Reply With Quote
Old 08-31-2000, 02:37 PM
Posts: n/a
Hi Steve,

Thanks for the advice. My mechanic has replaced the OVP relay with a similar one from another car. Still did not solve the problem. I'm getting him to show me the part he'll be replacing and will let you know more. Spent $ 400 replacing the fuel pump and filter.

Reply With Quote
Old 08-31-2000, 06:51 PM
engatwork's Avatar
Join Date: May 2000
Location: Soperton, Ga. USA
Posts: 11,966
I had the same type of thing happen on a Mazda MPV that I had. Replaced the idle speed control device on the intake manifold and it solved the problem. In an emergency you can rap on it with a small (17 mm) wrench and it will return to normal operation.
good luck
'95 E320
Reply With Quote
Old 08-31-2000, 08:48 PM
Posts: n/a
It sounds to me that the ignition module in your distributor is knackered (providing these cars have an ignition module).

My girlfriends 87 ford laser had the same problem being that it would stall at low revs when going round corners or at intersections. The replacement for the laser was about $120 (Australian) and it was a simple job. Remove distributor cap, replace module, replace distributor cap.

Hope this is of some help.


84 300GD
Reply With Quote
Old 08-31-2000, 10:20 PM
Registered User
Join Date: Mar 1999
Location: Suwanee, GA, USA
Posts: 4,712
Be careful, you can chase this for a long time. I have seen this caused by no less than 6 different things.

Have a proper diagnosis done and all will save money.

Donnie Drummonds
Reply With Quote
Old 09-01-2000, 09:07 AM
Join Date: Mar 1999
Location: Tucker, Ga USA
Posts: 12,153
Read many posts on air flow sensor as this part is crutial to "coast" idle stability durning decel.
Reply With Quote


Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is On
Trackbacks are On
Pingbacks are On
Refbacks are On

Similar Threads
Thread Thread Starter Forum Replies Last Post
Restoring an AMG Hammer Wagon, my story Part 1 Hammer Wagon Mercedes-Benz Performance Paddock 19 09-06-2011 10:24 PM
My beautiful car has been destroyed JHZR2 Diesel Discussion 49 12-20-2004 03:06 AM
help, car dies abruptly then starts right up kmbonomo Mercedes-Benz SL Discussion Forum 6 09-30-2004 04:53 PM
Stuff that makes you wonder. Post your pictures!! Cap'n Carageous Off-Topic Discussion 88 11-01-2003 04:15 PM
car dies when warm andievwguy Tech Help 3 07-24-2000 03:32 PM

All times are GMT -4. The time now is 10:51 PM.

Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2018, vBulletin Solutions, Inc.
Search Engine Optimization by vBSEO 3.6.0
Copyright 2018 Pelican Parts, LLC - Posts may be archived for display on the Peach Parts or Pelican Parts Website -    DMCA Registered Agent Contact Page