EVEN MORE 190E COLD START PROBLEMS!!! HELP!!

[elpueco]

My '93 190e 2ltr. auto is driving me nuts!.
When I turn her over from cold, she starts straight away on about 1200 revs, but drops straight away to about 500 revs on three cylinders, and then dies.
After repeating this about three times,she drops to about 500 revs then picks up to approx 900 revs, increasing to about 1300 revs as she gets to normal running temp.
She has a "cat" so no adjustment is available, has any body out there had this problem and cured it,It's making a happy man very old !!! :? :?

 

[Neilc]

Hi,

Sounds like you have no post cold-start mixture enrichment. Generally this is ECU controlled and effected by the EHA on the fuel distributor atop the air flow meter unit. The ECU does this by inputs from various sensors on the engine. I won't go into the detail in case it gets confusing at the moment.

You need a manual of some sort so you can diagnose the following faults and locate the components I'm talking about. You'll also need an automotive digital multimeter preferably one that supports duty cycle. I'd also get a std analog multimeter one that measures milliamps as low as 0.5ma.

Check the Coolant Temperature sensor. Should be a large black, rubberised conical connector atop the water pump. Around it will probably be a two pin connector for the fan switch and a one pin connector for the dashboard temp gauge. This 4 way connector handles coolant temp reporting for the ignition and fuel computers. You read the resistance of the pins opposite each other. Read these when the car is cold, and above 80 deg C and report back here. Set your multimeter to about 20K and it should be in range - sorry this is from memory try the different scales if you see infinity.

To be frank it could be a million things but best to check one at a time. For example it could be: Zero position of air flow meter, mixture or basic position adjustment of the air flow meter, idle speed regulator clogged or malfunctioning, manfunctioning coolant temp sensor, malfunctioning over voltage protection relay (does your ABS light stay on while driving?), malfunction ECU, malfunctioning EHA (electro hydraulic actuator), failed fuel distributor etc etc etc ad infinitum... Just hit the things one at a time. It took me six weeks to solve my problem with my air flow meter but I got it in the end and I'd never been near a 190 (16V) before.. Good luck and report back if you need to.

Cheers,
Neil

 

[elpueco]

190E COLD START PROBLEM

Cheers mate,
Thanks for your response, I was beginning to think no-one cared .
Have taken all your comments on board, and passed them on to my mechanic. I'll let you know how I get on.
Just to add insult to injury, since I posted my request for help, the fan has stopped working and the cruise control has packed up. Oh well, that's life!.

Thanks again. Elpueco.