190e cold start/idle problem

Jul 08, 2005 4 Replies
M

I am looking for a little net.knowledge on what might be wrong with my



88 mercedes 190e 2.3.

It is hard to start when cold. Pump the pedal to force an enrichment cycle while turning the key and it will start but the idle is real low and gets back to normal after a minute of idling. I have gone thru what parts of the testing covered in the factory manual and the only thing I can say is that the decel function does not seem to work as advertised.



I tried replacing the fuel pump relay to no avail - still the same problem. The idle air motor/valve was replaced about two years back. I pulled that and cleaned it out just in case it was dirty/jambed.



The frustrating part is once the motor has run for a minute it will start again and runs. There just does not seem to be any idle speed control.



Any suggestions out there?


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T

Fuel injected engines have a "cold start subsystem" - something that enriches the air / fuel ratio for the first few seconds of running. I'm no expert on all the varieties of gas engines' injection systems so I have to leave it at that for fear of giving you disinformation.

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C

If I am not mistaking,you have the KE-jetronic fuel injection.There are only a limited amount of adjustments you can perform.Check the airflow potentiometer resistance between terminals 14 & 18 for a resistance of

3,200 and 4,800 ohms when airflow sensor is at rest.Between terminal 14 and 17 there should be 560 and 1,060 ohms.When the airflow sensor plate is moved by hand to its greatest point there should be 3,760 to 5,640 ohms and adjust to specs.

Another thing to consider is a defective coolant temperature sensor,as this is VERY critical to proper cold engine operation.

You described having to put your foot on accelerator pedal,did you by chance move the throttle positioning switch?Fuel injected vehicles do not require pumping the pedal and is also not recommended.

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M

I checked the throttle position switch for function and it seems to work correctly according to the tests. Otherwise, it was not touched.

I tried checking the coolant temperature sensor over the weekend and it might be off. At the indicated temperature ( both cold/ambient and once warmed up ) it seemed to be showing less resistance than it should according to the charts. I might just pick one up and try that tomorrow.

Thanks

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T

My bro had this problem when we had the 190E 2.3... There is a black metal valve... kinda rectangular squarish that is attached near by the fuel distributor... it was leaking and I simply replaced it with a new one and orings.

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