I have been trying to fix this for some time now and have tried everything I have been told to fix the problem. It is still there so I was letting it run and found what caused it on my car and maybe yours. When my car warms up all the way the fan turns on after short time to help regulate the engine temp. Well on my car as soon as the fan kicks on and causes a kind of power surge, the idle drops suddenly and almosts stalls then goes right back up and works fine until the fan shuts off, you probably so this happen to a TV many times in your life. It will do this every time the fan turns on at idle. If the car is moving like driving down the street at say 30 and the fan turns on that is when I get a surge instead of the almost stalling thing. If I unplug the fan the problem goes away but fan dont work and I think that could cause a overheating problem. If this help any one great. If u can help fix the the fan "power surge" cause that is what it is, that would be great.

i would not recomend unplugging your cooling fan... it could get nasty, esp in the summer.

Your ecu kicks on the fans, so I would be looking for either a short somewhere in the wiring, or maybe your ecu is kaputz.


oh.. one question. how does you car respond to acessories being turned on? does it dim your bulbs? do lights dim when you hit your brakes?

Sounds like you have a short somewhere in the wiring, or like ^^^^ said, maybe your ECU is crapping out on you. Have you done anything in the engine bay lately where you might have sliced or pinched a wire for the fans? I would trace out all your wiring and see if there is something wrong there. Also get a load test done on your battery and alternator and see if they are both in good shape. It does seem weird that it does 2 totally different actions depending on if you are driving or at idle which would lead me to believe it might be ECU related. Wish I could help more.....

its good to see that someone else has noticed this as well. my car idles poorly (low) ONLY in stoplight type traffic, but if ive just come off the interstate or have been driving fast and come to a stop, the idle is fine. i would assume that because theres higher airflow, the fan doesnt kick in, but when im in traffic, the fan comes on.

my alternator and battery are both new, and i have no light dimming, etc. associated with a bad electrical system.

i think im going to investigate this some more this nex weekend sometime. hmm.....

I have alredy replaced the ecu battery and alternator. I dont want to screw with the electrical cause I want to keep my car. Thanx though I am learning to live with it.

You might want to try rewiring the fuel pump - http://www.2gnt.com/www/corbin/rewire.html

I know it says for turbo & nitrous guys, but I recently installed an intank Walbro and noticed that while the engine is idling the pump cuts-out briefly when the fan comes on. The new pump is really loud so it's very easy to hear. I haven't rewired my fuel pump, but I'm hoping that it'll get rid of the cut-out when the fan comes on.


95 Eclipse RS : 5 speed
Jeep TB writeup - http://www.dimensia.com:81/jimbo/JeepTBfor2gnt.html