190e cold start/idle problem

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Melvin Dillon - 08 Jul 2005 04:22 GMT

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.G. Lambach - 09 Jul 2005 02:45 GMT

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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CaptainW116 - 09 Jul 2005 09:13 GMT

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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Melvin Dillon - 11 Jul 2005 23:43 GMT

> 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
[quoted text clipped - 10 lines]
> chance move the throttle positioning switch?Fuel injected vehicles do
> not require pumping the pedal and is also not recommended.

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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Tiger - 15 Jul 2005 18:00 GMT

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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