PeachParts Mercedes-Benz Forum

PeachParts Mercedes-Benz Forum (
-   Tech Help (
-   -   1985 500SEL Euro Spec having difficulty starting (

hawkpfc2 12-24-2000 10:37 AM

I am in the Philadelphia area, normally I garage my cars, but as of late, I have been unable to garage my 500SEL. Whenever the engine is not warm, it has trouble starting. Hope it is not something expensive like the distributor cap or rotor, but if you think it is, will get fixed asap. A few days ago, could not get the car started except to hold the revs by hand for a minute. I also heard I may have problem with the idle control motor and my trans is a little rough shifting at the moment. Most likely the vacuum modulater as the trans was in good shape as last checked maybe 20,000 miles ago. Also, if there are any other Mercedes fans on the board in this area, let me know.

Thanks much,

stevebfl 12-24-2000 11:36 AM

You should have simple K-Jet (CIS)on the European 500SEL. Cold starting and running depend mostly on the control pressure regulator (otherwise called warm-up pressure regulator).

If you haven't done it within 20k I would replace your spark plugs. You should view them to tell the story on what's happening to your motor. Look for differences in color and carbon build-up. Set your timing at least 5 degrees above current setting (factory setting that is). These two things will probably give temporary benefit to starting. If it isn't running properly you will have reduced vacuum and as a result high modulator pressure and hard shifts. Fix the running before dealing with the tranny (except if you also should service it).

If you would like to know about testing the warm-up pressure regulator let me know. It will require fuel pressure gauges!

hawkpfc2 12-24-2000 11:39 AM

I believe I am using Platinums on the car

Is it as big of a problem on the 500 V8 as on the 300E's where I know it is a large problem?


hawkpfc2 12-24-2000 11:40 AM

This would confirm what I believe
Would that also have my economy meter show a high reading?At idle, it is close to 1/2 way up the meter and as soon as you accelerate, it goes into the red zone.


stevebfl 12-24-2000 12:05 PM

Get rid of the Platinums, could be all your problem. Probably not though. Sounds like you have a big performance problem from the data on the economy gauge. It is a vacuum gauge and you should be all the way to the left (high) at idle and you should be able to accelerate without going into the red. Heavy acceleration will of course take you to the red but a casual acceleration should be possible without going into the read The higher the vacuum reading at every power output the better your engine is performing.

These vacuum readings are surely responsible for your hard shifting.

hawkpfc2 12-24-2000 12:10 PM

One more thing I neglected to mention
A few months ago, the idle motor was found to have a short. However, my mechanic programmed the computer to set the idle by hand at 700 rpm instead of let the computer do it and cause a short. Would that also cause the problem? Just curious to know if they are related.


All times are GMT -4. The time now is 07:38 PM.

Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2022, 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