rollininthebenz

Hello,
I am new to everything Mercedes Benz, but not to working on cars. I have mostly worked on older carburated vehicles such as Datsun and Toyotas but now need some assistance with my vehicle. I have recently purchased a 1991 190e with the 2.6 and 190k miles on it.




When I purchased the vehicle it had a little bit of work that needed to be done. It is extremely well kept inside and out. The problem lied in the engine, it would shut down when it reached operating temperature and would start back up about 30 minutes later. When I was driving it home from purchasing it, the vehicle died in my driveway and now will not start. It has not started in about 3 weeks now.

We have replaced the OVP and the 10A fuses inside of it, the idle air control valve, cap and rotor with genuine Bosch parts from the dealership, CPS with a new one to test it out, and Bosch spark plugs from the Mercedes Benz dealership. I am getting a bright blue spark coming from all 6 spark plugs,

What is happening now is that it will just crank and crank but will not start, or even give me a pop or anything. I will remove the spark plugs and they are fuel fouled. The fuel injectors are brass which according to a MB technician indicates that they have been replaced since they are not the original steel color. I have tried starting the vehicle with the cold start valve disconnected. Would the fuel distributor be the next component to test? Or possibly the fuel pressure regulator? I am new to the CIS-E system and am learning and reading everyday but I am at a stand still and any help would be greatly appreciated.

An added note that the previous owner had let me know was that he had messed with the fuel mixture adjustment screw on the top of the potentiometer. He had achieved 49% on the duty cycle reading but I have since tested the o2 sensor and it is bad, also the diagnostic light diode gave me an o2 sensor code. Could the mixture adjustment screw on the potentiometer be adjusted too rich and dumping excess fuel during start up?

Thanks in advance and I am looking forward to being a proud w201 owner for years to come!

rollininthebenz

So today it finally stopped raining and I got a chance to do some checking out.
I removed the fuel lines from the distributor to the injectors. I turned the key to key on engine off and saw no fuel coming out of the fuel line connections on the top of the fuel distributor. I then cranked the vehicle, with the fuel lines still disconnected and no fuel came out of the top of the distributor. I tried it a couple of more time and still no fuel.

I manually pushed the flap on the potentiometer down with my hand and I got a strong smell of raw gasoline coming from inside the potentiometer. I will be looking at some information that I have printed out about the CIS-e system today.

rollininthebenz

So today I have ordered a used fuel distributor as a testing ground before I get into the whole rebuilding process. Does anyone out there have any experience or advice on rebuilding the top half of the distributor or any other idea on what else could be flooding the engine?

Frnak

Did the new fuel distributor fix your problem? I have no experience with this car but could the previous owner have buggered the potentiometer? If that's the last thing he messed with I'd be looking there.
Frank

rollininthebenz

Hi Frank,

Sorry for the late response, I am waiting the new gasket and diaphragm kit for the fuel distributor. I leaned the mixture screw out a turn and it was still dumping a lot of fuel. None of it however is coming out of the I injector ports on top of the fuel distributor. However it all seems to be going down the intake manifold such as a carburetor would.

rollininthebenz

So, it's been a few months and I finally got the engine to run. It took about 20 turns for the vehicle to start. It idled very rough but it idled for about 10 minutes or so. The engine would "hunt" for idle between 500 - 1500 rpm back and forth. When I put my foot on the gas it started to stumble like it was starving for gas. I then shut it off and re started it and it roughly idled again. I held my foot on the gas and it stayed at 3000k rpm for about 5 seconds very smoothly. When I took my foot of the gas it fell on its face and turned off.

I have since, swapped out the MAS relay, OVP relay, and Potentiometer with eha, fuel distributor and ECU all from a running car and it did not make a difference. I also cleaned my injectors per the MercedesSource machine and procedures until I heard the high pitch squealing sound and had a cone spray. I have tested the fuel pressure at the fuel distributor before the regulator and after the regulator. I used a cheap Harbor Freight gauge, but regardless, I showed 3.0 bar before the regulator and 2.8 after the regulator. The EZL is within specs and I tested it per WIS testing procedures. I also tested the ignition coil and that is within specs as well.

I let the vehicle sit for a week and when I went to start it again, no start. I looked down the throat of the intake and had a puddle of gasoline about 5/16" deep. I don't know where the gas may be leaking into the intake from. It is not starting again and I'm starting to lose my drive to keep at it.

One more thing to note, when I crank the car to get it to start, it just keeps turning until I push down on the brake pedal all the way. It will start to stumble to a start. I tested the hard line on the brake booster and it held vacuum one way.

Sorry for the long response but I hope I can get some guidance or help in the right direction.

rollininthebenz

Also, I forgot to add that the cap and rotor are brand new Bosch from the dealership.