Strange High Idle 88 2.3L 190e
 

My mechanic power washed the engine compartment and now I have a high idle problem. So I took it back done, but he could find any hoses that were knocked off or loose. He also tried tapping on the idle control valve, but that didn't seem to effect it.
His last effort was to check the OVP, but the fuses were fine.

Does anyone have any suggestion as to what else I might try to bring the idle speed down?

Thanks

Check the throttle valve switch (idle and WOT circuits) and linkage microswitch for proper function.

Remove all the electrical connectors and check them for corrosion or dirt.

Find a new mechanic who doesn't use a hammer as the first diagnostic tool!

Duke

Thanks for the tip. As for the mechanic, he didn't use a hammer, but he was trying to see if the idle control valve was sticking.

Thanks

Especially after an engine wash the most likely suspect would be an electical connector or switch.
I never use high pressure water to wash an engine - just Gunk and a light spray rinse from a garden hose. High velocity water from a pressure washer can get into places where you don't want it, and sometimes the water can't get back out.

Duke

I removed the air filter housing and started checking electrical connections to items such as EHA, idle control valve, and air flow meter. None of them seem corroded, but I did wipe them off. It didn't seem to help. If I adjust the air flow meter the revs come down, but then it idles pretty rough so then I turn it back up slightly. However, if I turn it off and let it sit a minute, it has a hard time starting unless I increase the fuel mixture.

I am not sure if I check the items you mentioned in your first reply. Where are the, "throttle valve switch (idle and WOT circuits) and linkage microswitch for proper function" located? I am not to savy when it comes to knowing car lingo.

Again, I appreciate your time and help.

Gards

The throttle switch is at the end of the throttle shaft and has a pigtail connector along the top of the manifold that can be disconnected to check function - ground, idle, and WOT.

The microswich is on the linkage.

Duke

If cold high idle is normal, then check temp sensor contacts for corrosion. Also check the hose from the idle control valve to the bottom of the airflow meter plenum - it might have been knocked off. Also, don't forget to check contacts on the Bosch computer boxes behind the access panel, if high-pressure water entered there.

A general rule of attack, though, is not to adjust something that could not possibly have caused the problem - such as the mechanical mixture control. Now, in addition, you have a screwed-up mixture adjustment that will only add to the complexity of solving the problem.

Steve

I will check both of your suggestions and let you both know.

Thanks,

Gards

Okay, I found the throttle switch and disconnected the wire and it looked alright. It did cause the car to die, though I am not sure if that is normal, maybe you will know. Anyway, I also checked all the electric connections and they seem okay. Although, I don't know which one is the tempature sensor, but my guess is that is just to the right of the oil filler cap and is blue. I say blue because it is the same color as the cold start valve.

As for the hose on the plenum and the idle control value, it was was on securely.

Well thanks for the help.

Gards

Listen to words of wisdom
 

"A general rule of attack, though, is not to adjust something that could not possibly have caused the problem - such as the mechanical mixture control. Now, in addition, you have a screwed-up mixture adjustment that will only add to the complexity of solving the problem."

Can this be printed right on the air cleaner of every car please! A big sticker which says

WARNING: Do not touch anything you do not understand or you will be adding to the complexity of solving the problem for those that do understand.

Look at things, check for bad contacts and replace the connectors, look at things others suggest but DO NOT just flit about adjusting things, the pressure washer could not have turned the adjuster you decided to mess with could it? Think about what you are doing and you will lower your frustration and expense (and the frustration of your mechanic).

When teaching people how to tune-up thier car I always suggest that they do one thing at a time and test. Replace one plug at a time and when the plugs are done, start the car. If it runs, go ahead and repalce the cap and rotor, then start the car, if it runs go on. In this way you only have to backtrack one step to find the fault rather than changing everything then discovering that you have an issue and having to check everything from the beginning.

Chris