Stalling problem PLEASE HELP
 

anyone?

Does this car have a mechanical or electronic fuel injection system ? I am not very familiar with this car but if it were happening to my 87, 260E, these are the things I would check.

Coolant temp sensor that sends engine temp to the fuel injection computer and the ignition control unit. On my 260E, the sensor has 2.5 to 3.5K resistance when engine is cold and then the resistance decreases to between 250 and 350 ohms when the engine reaches 80 deg-c

vaccum and fuel leaks

it has electronic fuel injection,has the bosch cis-e system

CIS-E is mechanical injection, right ? Do you have an air sensor with a large plate or do you have a heated film or heated rod type air sensor ?

CIS-E is the same as KE-JET, I think (continuous injection). Easy to tell, if you have a heated wire MAS it's LH type, air meter plate under the air filter it's KE-Jet

You did not mention ignition parts -- check condition of cap, rotor, wires, and plugs. Carbon tracks in the cap will cause all sorts of trouble.

Check for vacuum leaks (idle control valve, boot between air meter horn and injector seals).

Check the temperature of the fuel pump relay -- if it's quite warm after a short run, replace it (this cured all sorts of starting/idle ills on my TE). If it stalls while driving, definitely replace it.

Replace the OVP -- the problem with it is that it is usually intermittant, rarely goes totally dead right away, and is vibration sensitive. If it has one fuse on top, its original.

Peter

Correct if im wrong but if the ovp was broken it wouldnt be getting voltage?
I dont think the mas unit is getting warm but ill look closer tommorow.

This problem is really getting annoying and getting to the end of my wits with this hunk of junk. My vw 96 jetta isnt this kind of pain in the ass to track down a problem like this.

The OVP is a tricky bugger, often it will seem fine cold or sometimes warm, but it is a touchy git and will often be very very intermittent, I would consider a new fuel pump relay and an OVP, excpecially if it is original

I just had a problem like that. It turned out to be the crank sensor on the bell housing. Normally it's about 1000 ohms but I cought it shorted. An indication was the tach going to zero when it quit even though the engine was still spinning, coasting actually. A suggestion would to re-seat it.

The OVP provides conditioned electricity to the electronics (engine controls, climate control) to prevent a voltage surge from frying them. If it is bad or intermittant, it will interrupt current supply to the engine computer, ignition module, and so forth, giving you erratic running. You have to measure the output, not whether or not it has current supply.

On a 91 you probably have electronic injection, not KE-jet (definitely if you have a MASS unit instead of individual relays). I don't know if the fuel pump is operated via the "big box" or via a standard fuel pump relay.

You need to pull the trouble codes before getting all bent out of shape, that system has on-board diagnostics and will tell you what isn't working.

Peter

The fuel pump is operated by the mas which has the relay for the fuel pump along with other things.
the ovp is reading 20ma by the ehl.
I dont have the money at the moment to buy the special diagnostic tools for the car. Knowing how mercedes makes their cars so you have to bring it to a dealership I most likely wont be able to rent the diagnostic tools.

that ovp has at least two circuits in it,when the one feeding the f.i. computer drops out the car is running in limp mode.i would replace the ovp just on principal first.your car has the fuel distributor with the black eha screwed to the side and when you start car the computer sends signal [40-60ma]to get enough fuel to start.if no power to comp----you get the picture.the other thing you can do is to use a 3mm allen at the tower in front of distributor and push down and twist about a 30deg turn clockwise which should make rich enough for starting.hopefully the ball bearing in top of tower has been removed.

You MUST eliminate any vacuum leaks before it's gonna run right. Very likely you have bad idle control valve hoses and a bad boot between the air meter horn and the throttle body. Fix those and you will get it started, anyway.

Peter

K ill look for vacuum leaks tommorow

An update. I have just checked my spark plugs and they are BLACk. So my engine is running rich. Something is telling the control unit to send too much gas and choking the motor. Also my water temperature sensor is picking up 1300 ohms at the ezl and that info is being sent to the control unit. this doesnt sound right. And I also forgot to mention this is a calfornia model with 4 plugs instead of the normal 3 on the ezl. So do i have to replace my ezl?