500SEL stumble / hesitation
 

Acquired an 85 500SEL....


Its got a few problems, working them out slowly. The current problem that I am trying to fix is a stumble/hesitation under light acceleration. If I go WOT the acceleration is fine, but less than wot, it stumbles. It doesnt do it all the time, but its does not favor hotter or colder.

I swapped in 2 different fuel pressure regulators, and both had the same problem. I have acquired a third, and am going to try and see if its better. Some people told me to clean the ICV to see if it improves. Checked for vacuum leaks, and there does not seem to be any...


You guys have any other ideas?

Just drive WOT all the time? :D :D

Could it be an injector issue? Or maybe a computer issue?

hesitation
 

you could have a few things going on. check the fuel injectors. also check for any vacuum leaks. how is it at idle. is it rough? are there any lights on the dash. what about the coolant temp sensor? what is he air fuel ratio set at? lots of questions have to be answered. it is a process of elimination to get there. hope this helps

Check fuses for clean contact. Try swapping the OVP.

Check out this post:

http://www.peachparts.com/shopforum/tech-help/104289-adjusting-eha-possible.html

I was having a similar problem and it turned out to be a lean mixture. Now runs great under all conditions.