Custnam

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,

hondadude

Grab up your handy dandy multi meter;

With the engine idling, touch one test lead of your voltmeter to the battery positive (+) post, and the other test lead to the BAT (B+) terminal of the cooling fan connector, when the fan turns on to run the voltmeter should read less than 0.2 volts.

Likewise you can check the ground circuit, one meter lead to the neg post of the battery, the other to the neg terminal of the fan connector, again less than 0.2 volts.

battery terminal connections clean and tight?

Custnam

10-21-08

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.

10-23-08

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 on Id guess the idle drop to be about 400-500 almost stalling the car, then it comes back up, but.... heres another strange thing, It also runs alot more rough when the fan 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 when the fans not on and it ran much rougher at that RPM with the fan on than it did at that same RPM when the fans not on. So something that controls the RPM when the 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 connector and 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. 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. ????????


10-24-08

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 hoping a used compressor isnt going to be a ton of cash. It has to be that right?

10-29-08

Ok so heres another update: After all the other parts and fixes Ive tried (read above posts). I decided to try another before I give up and take it to a mechanic (ouch to the pride!!) I read one of the posts in the DYI forum about idle issues. After 3 different IACV''''s I tried to see if maybe it was the FITV staying open or something like that. So I took it off and was able to get the whole intake top assembly off, and got the FITV off but not before I broke 2 bolts off. The previous owner lived near the ocean here so aside from the bad paint, the engine, etc. has a alot of salt corrosion, so almost every part I take off breaks a bolt. But anywho I took the new FITV, cleaned it up and tested the thermostat following all the instructions from the DIY, and of course it still does it.

Im hoping someone that reads this can figure this out, because honestly Im stumped on this one. One other detail I can add that may help someone figure this out. When Im in the car and the cooling fan comes on, I can hear the same sound cominf from the vents that the a/c makes while the compressor runs, its hard to describe the sound, but all cars make it. The same sound you hear from the vents when you turn off your a/c. Like the freon thats left escaping. So I know this must be compressor/condenser/AC related.

hondadude

diode pak

Mr Yamada

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by hondadude &raquo;</TD></TR><TR><TD CLASS="quote">diode pak</TD></TR></TABLE>
Or the ground is being backfed positive voltage.

The reasoning is thus; when the fans run with the A/C button pushed, there is an A/C idle boost circuit.
When the fans run and for whatever reason causes the compressor clutch to engage the idle boost is not working.

Replacement of the compressor will not solve the problem, a correct and accurate diagnose is needed, not throwing part$ at the problem.