I have a 1995 Honda Accord LX ,2.2 L. Im having a problem with my cooling fan. When the car is running and idling (for example at a stoplight) and the fan comes on to cool the engine down, the idle drops so far down the car almost dies. But comes right back to normal right away. Just when it initially kicks on. Now I know when some electrical components are on the electrical pull makes the car idle a little lower, like the a/c. But this is different. And it ONLY happens with the cooling fan, not the a/c or any other component. Ive changed the cooling fan relay, no help. So I tested the fan individually by running it straight to the battery while the cars running. And it kicks on perfectly, runs nice, quiet, and smooth with no idle drop at all. I was almost sure it was the motor in the cooling fan going bad, and pulling too much amperage when it initially kicks on, but if this was true it wouldve happened when I did the separate test. So its something from the fan inward. Im hoping someone else has had this happen and was able to fix it. Im running out of ideas here,

 

I assume you have AC. When cooling fan comes on, both cooling fan and compressor engage if AC is On. AC load & fan loads are significant and the ECU is supposed to compensate by increasing throttle (more air) with the Idle Air Control Valve (IACV) to prevent rpm sagging when these components come on. If the IACV is stuck closed w/ dirt/grime or non-working, the rpm will sag. Your IACV may be initially sticking and then working.

Usual fix is to remove the IACV and clean valve movement. Clean throttle bore and IACV inlet/outlet passages. Use throttle body cleaner. Do not clean electrical solenoid w/ throttle body cleaner as this can damage the solenoid windings.

Look at DIY section for a download manual for 94-97 Accords, or go to Autozone for help.

good luck

 

Ok, heres a list of what Ive done and it still does the same thing. I got a IACV from the junkyard and cleaned it up very well, I put in a brand new alternator and battery (even though it didnt fix the issue still ok since they were old). The new alternator helped a little, but it still bogs down very low on the idle when the fan kicks on. I read somewhere else that the cooling fan temp switch by the thermostat can cause irratic idle if its not sending the correct temp to the ECU. So Im most likely going to get one just to rule that out. I will also check on what a used fan will cost at the local junkyard also. If that doesnt fix it then I have no idea whats causing this to happen.

 

You never answered my question? Do you have AC and is it on when idle goes low?

good luck

 

, car should have 2 fans,( driver side, a/c fan ) ( pass side, main cooling fan ) and both should come on to cool the engine when coolant reaches a certain temp..or when the a/c is turned on..

Do BOTH fan come on ?????

also chk the base idle... unplug the iacv valve, idle should be around 500-550 rpm, if not adjust it to be that, plug iacv connector back in idle should go to 700-750.. \chk engine lite will come on with iacv connector unplugged but just pull the back up fuse to clear the lite

 

ok , heres an update. It does have ac, so yes 2 fans. It only happens with the cooling fan. There is a very minimal drop when I turn on AC which is normal. Like maybe a 50 RPM drop. When the cooling fan comes onId guess the idle drop to be about 400-500 almost stalling the car, then it comes backup, but.... heres another strange thing,It also runs alot more rough when thefan is on,which is of course normal with the idle drop, but I did a test to see if the running rough was just because the idle dropped. I let the car idle on its own until the fan kicked on and dropped the idle,I pressed the gas down to get it back up to its idle whenthe fans not on and it ran much rougher at thatRPM with the fan on than it did at thatsame RPM whenthe fans not on. So something that controls the RPM whenthe fan is on isnt working right and making it not only drop idle way down, its also causing it to run much rougher.I also did a test by unplugging the fan connectorand running a jumper a jumper straight to battery while its running and it does not die down anywhere near as close this way. So I dont think its the fan itslef. I thought it might be the fan motor being worn and causing a high amperage draw when it first kicked on causing the big idle drop. But if this was the case it should have happened the same way when I ran the jumper. So honestly Im at a loss here. Another strange thing is my car does that might help. When adjusting the idle screw to raise the idle it wont adjust any higher than about 700 RPM. Yje screw gets to a certain point then has no affect on the idle, and you can screw the idle screw all the way in and it stays at about 500 or so. Is it normal to have such a little amount of adjustment? Maybe this is related. Like I said Im at a loss here and frustrated alot. Ive used all sorts of forums to figure out various things so Im hoping again I can get this stumper figured out without dolling out even more cash. [&o]

 

PS, I noticed when the AC is on and the cooling fan kicks on that the rpm drop is less than if just the cooling fan comes on when the AC is not on. ????????

 

Maybe I got another bad IACV? Im at a loss here guys

 

Have you checked that IAVC opens/closes when 12V is applied/removed?

When you cleaned the IACV did you clean the upstream and downstream paths to/from the IACV? If these are blocked a working IACV won't help.

Clean the throttle plate front and back and inside of throttle body bore on both sides of throttle plate.

Your car has all symptoms of non-working IAC system.

good luck

 

UPDATE: Ok, So I went to the junkyard again today and got another IACV hoping I just got unlucky with the other. I cleaned it up really good with carb cleaner, installed it and still same thing. So I sat there frustrated and decided to listen to the car run the fan on and off through a few cycles. Then I did the fan straight to battery test again and it worked just fine that way again, the idle barely dropped at all when 12v applied straight from battery to fan. While listening to to it I noticed a click and a hum that comes on when it kicks on while in the circuit. So I got real close and finally could tell where it was coming from. It was the coming from the a/c compressor. I didnt know this but I guess the compressor activates when the cooling fan comes on as well as when the a/c is on??? I thought just the cooling fan came on until the a/c was actually turned on and running. So to test this I removed the a/c compressor fuse and let it run, the cooling fan came on just as before and ran perfect. No idle drop at all! So I guess Im heading back to the same place Monday and hopinga used compressor isnt going to be a ton of cash. It has to be that right?