92 MB 190E 2.3L need help with poor idle diagnosis
 

Hello Everyone

I have a 92 MB 190E 2.3L with a starting and running issue.

Basically when cold, it starts but during cranking the rpm needle will sometimes erratically bounce up to approx. 5k rpm then it starts....

Once running it will run at 500rpm (about 250rpm too low) and shudder until the engine temp needle moves a little bit.

I changed vacuum lines from idle air control valve becasue the car was idling too low before at all times.

Now it idles fine when warm but it has the above problems.

I am wondering how to tackle this problem.

So far:

1. Checked OVP, fuse fine



2.Swapped OVP for another one, no difference

3.* Idle control valve: (bet intake cyl 2 and 3) checked, its clean and the little valve opens when engine cold once I turn ignition key.

4. Replaced few vacuum tubes/ hoses from idle control valve to the T split and checked for cracks etc...

5. Cold start valve? How to check?


*I am not sure how to properly diagnose the cold start valve, I only checked that it opens and closes


All these parts are pretty $$ and I do not want to start replacing them for no reason..

Thanks for reading :)

Next thing to check is the air flow meter. Do a ohms test on the air flap by hooking your meter to the two top poles of the electrical plug and pushing down on the air flap slowly. You should see a steady change in the ohms value and no jumping.

[QUOTE=BENZ TEK;1328389.[/QUOTE]

Thanks , I will do that :cool:

Check Water Temp Sensor. If bad the CIS-E ECU does not know the engine temp is too cold and will not fire the Cold Start Valve or give fuel enrichment and raise idle to warm the engine properly.

Thanks for the replies:)