1985 190e crankes good but will not start
 

My 85 190e will not start when i run 12v to the cold start valve it runs fine but other then that it will only crank. possible there is a relay that controlls the cold start valve not sure which it is or where it is located i might be looking totaly in the wrong direction any help would be awsome thank you:confused:

The cold start valve is designed to HELP with starting ONLY on very cold mornings! Doesn't even operate below 59F on that engine & only while the starter is engaged.

FUEL pressure is the key for a CIS car to start..The injectors need at least 55PSI to push them open...system pressure on that engine should be around 80PSI...That would be MY starting point..making sure that there is enough fuel pressure.

OF course a vacuum leak from one of the idle air valve hoses will cause the same problem.

Relay??
 

I spoke with a 190e owner the other day who was happy to share that many MB's have a relay located right behind the battery of his 190e that when it goes bad causes it not tostart.

He said he learned this from Click&Clack (NPR).

I believe the question was "Where is the cold start relay"?

MB's don't have cold start relays!

That car does have FUEL pump relay & overvoltage relay....
Bad info on a post can complicate diagnosis

And to help with the fuel pressure diagnosis, read what Steve Brotherton had to say in this thread:

http://www.peachparts.com/shopforum/tech-help/150797-89-560-sec-died-parking-lot-please-h-e-l-p.html?highlight=airfilter

It's not necessarily a conclusive pressure test, but maybe good enough to give you a ball park idea of where you stand.