Auto Racing: Major car problem please respond, electronic control unit, electronic sensors

Question
Hi, I could find no one else to ask this question and since you mentioned you build cars and know engine work I thought maybe you can help. Today when my girlfriend came to pick me up from work she stopped the car and it sounded like it was idling terrible. the rpms would jump from about 1000 to over 2000, and would keep going back and forth, she said the fan would run kind of long after the car was turned off. the coolant in the resevour was also low i couldnt check the radiator because the car was hot. oh by the way i didnt mention its a 94 honda accord. Anyways there was no heat in the car and the temp gauge was pegged at hot, when youd try to stop or let off the gas the car would accelerate itself and the rpms wowuld still fluctuate. if there is any idea of what could be wrong please get back to me it would be much appreciated, thanks Al Kane

Answer
HI Al.

Newer cars rely on a system of electronic sensors and an electronic control unit, or ECU to keep the engine running well.  The fact that your engine isn't particularly hot, yet the heat guage is pegged, indicates that at least the heat sensor is shot.  There are probably others.

The best thing I can suggest to you is that you obtain an engine scanner from a local parts house, making sure the one you get works well with Hondas.  Then sit and read the manuals and instructions until you have a feel for what the scanner does, and try it out.  

I'm betting that with this effort you will get much closer to the problem than you ever would by trying to second guess it.

Good luck

Dan Liddy
Sarasota, Florida