Idle too low with AC on...
 

I have a 2000 civic EX. I just bought car a month or so ago.

The car idles too low when the AC is on, to the point where the compressor does not operate correctly. The compressor makes "hiccup" type noise/action when the engine comes back down to idle. I know the AC system is charged correctly, I'm convinced it's an idle issue.

I've read I should be around 810 RPM at idle with the AC on and around 670 RPM with the AC off. I'm guessing I'm only around 500 RPM currently with the AC on.

I'm going to take the IACV off and clean it first. My question is if that doesn't work what should I do next? I've read that it could be the ECM not communicating with the IACV to increase idle when the AC goes on.

Thanks in advance for the help,

RS

Re: Idle too low with AC on...
 

If you're guessing at what the idle is I assume you have a DX with no tach?

Check all of your grounds, make sure they are clean and well connected. If not that, try kicking your idle up a little, if you don't know how to do that, I will post pics later but I'm at work right now and don't have access to it.

Re: Idle too low with AC on...
 

I've got an EX and it has a tach.

The idle seems fine with the AC off it's just too low with the AC on. I've got the factory manual and know how to adjust the idle. I'm just concerned with adjusting the idle if it's fine with the AC off.

I'll try and get some more accurate data on the what the RPM is at idle both with AC on and off.

Thanks,

RS

Re: Idle too low with AC on...
 

does the condenser fan come on when you turn the A/C on? take a look.

what happens is that the pressure goes high from lack of air across the condenser tripping the pressure switch and cutting the system off. then the pressure normalizes and the system cuts back on. off. on. off. on. when it is on it loads the engine more than usual, causing a low idle.

you're A/C should still work fine cruising down the interstate but lacks cooling below 45mph and idles funny sitting still, cutting the compressor on and off.

i've discovered the same issue with my '96. :thumbup:

Re: Idle too low with AC on...
 

Yes, my condenser fan comes on with the compressor. I also replaced the condenser when I replaced the compressor.

Are there some specs on the cond. fan so I can check to make sure it's operating correctly? I assume it is, rotation is correct and it feels to be moving a fair amount of air.

I notice if give it a little gas adding a few hundred RPM (about 750-800 total) it eliminates the compressor "hicup"

I know 810 RPM is the idle spec with the AC on and I'm no where near that, It's only about 450-500 RPM w/ AC on after the motor is warmed up.

I'm hesitate to increase total RPM as it seems to be within spec @ idle with AC off.

Thanks,

RS

Re: Idle too low with AC on...
 

So, did you ever find out the problem with your a/c issue? I am starting to get the same issue you are with my Honda CRX.

Re: Idle too low with AC on...
 

You have air in your system from a charge. You probably forgot to pull a vacuum line. This was my problem for the exact same issue.