[SHughes]

Ok, I´ve asked a couple of q´s about high idle thanks for your responses. Here is what I´ve found. The car warms up and everything is normal, then at a certain point the idle jumps up 400-500 rpm above normal idle. I can dis-connect the tps, o2 sensor and idle speed control valve and nothing changes. Rpm and driveability stays the same like the computer doesn´t react to any changes. Everything in the vehicle works like normal accept the cooling fan only will work with the key turned on. Is the computer bad? Or is there a relay that could have gone out that only controls the computer? Where is the best place to get a new computer? Thanks for any help you might be able to give.

[ This message was edited by: SHughes on 01-05-2003 11:17 ]

 

[egtdude]

I know this sounds to simple but have you checked all your grounds etc to make sure they are clean? also have you tested to see if there is an electrical draw on the system with the key off.. all doors shut etc. take the bulb out from the underhood light.

 

[SHughes]

All grounds are good, Not sure i understand about the draw on system. Would it effect the computer if the battery was out of the car for a day?

 

[Jeffescortlx]

The Engine coolent sensor effects idle.
I would take a closer lok at the idle control valve.

 

[SHughes]

Idle air control valve has been checked and is good. all temp sensors and swithes have been replaced and are good. Tps, and o2 sensor are new and check good. You let the car warm up and the idle jumps 400-500rpm and unplug all the sensors and nothing changes at all. I would think the computer would cause something to change when it isn´t getting feedback from the sensors.

 

[zzyzzx]

What happens when it´s doing the high idle thing and you disconnect just the IAC? It sounds as if you were disconnecting individual sensors and the IAC. If you disconnect the IAC and you still get the high idle then I´d be looking for a vacuum or air leak. You can get a vacuum leak from something other than a cracked vacuum line. I had one caused by a bad heat riser. You car might not have a haet riser (my 1995 Escort doesn´t) but it could still be your EGR valve or even the stuff for your HVAC in your dash that uses vacuum. The way to check these things is with a handheld vacuum pump connected to a gauge. You need to check everything that uses vacuum. Even the HVAC, the EGR, and that solenoid that goes to the EFE system.

I don´t see how it could possibly be your computer if it does the high idle with the IAC disconnected.

[ This message was edited by: zzyzzx on 01-05-2003 16:42 ]

 

[SHughes]

Ok will check for vacuum leaks, I see what you mean about the IAC. why doesn´t my cooling fan work with the key out? the high idle and the cooling fan motor not operating without the key on started at the same time. I was told today they are probably related.