Show 1151, Dec 17- Mercedes 190 problem

Tom and Ray, I think the guy fried the computer. In 1984, I believe the 190 was made in only two versions- the 190D diesel, and the 190E, gas with Bosch fuel injection. When the computer’s not operational in the 190E, it operates in so-called “limp-home” mode- there’s no priming shot, the auto-rich warmup function doesn’t work, and the symptoms are exactly what he described. I had an '82 Euro-model 190E which at one point had a faulty contact in its main harness connector, power was cut off from the engine computer and the symptoms were the same. Took me a LOT of hunting to find that one!
Best, Paul

I think Paul is on the right track, but one thing he should check first is the fuse in the overvoltage protection relay. It is a silver colored relay on the right side or the engine compartment near the firewall that has a plastic flip up lid. If you flip up the lid there is a common flat fuse (15A I think) inside. It was not unusual to have this fuse blown during a battery/ jump/connection misadventure. If it is blown the CIS E module will not have power and it will cause the engine to be very hard to start cold because there is no cold start enrichment. After the engine warms up it runs fairly well since it is an electronically assisted mechanical fuel injection system (Bosch KE). All of the US version 190s had fuel injection, although I think there was a carburetor version of the engine sold elsewhere in the world. I owned a 1985 190 that served as my work/home freeway flyer for many years. Worth a look anyway.


I just heard the program and I hope the poor guy checks in here. Sure sounds like they were leading him on a wild goose chase for a simple fuse.

Sorry, just heard the show today on podcast. What total BS Tom and Ray spewed today “Your cah hes a cahhburetor.”!! Maybe their hearing was bad and they heard 1890 Mercedes.

OVP relay like Benzdoc says.

Bring him back to stump the chumps!

HMMMM… Does an '89 300E have a similar fuse and situation? I know of one with similar symptoms.