I own a used 1999 Accord LX Manual, which I have run without any major problems for 3 and a half years, that is until now...
The car has begun to go through a whole league of problems, but by far the most annoying of which is its new idle hang-up:
My car rough idles when I turn my air conditioner on. If I attempt to reverse and press on the brakes for example, (with the AC on), the RPM dips to 300 or so with a slight shudder, then recovers within a second or two to its normal idle position. If I'm lucky however, it behaves perfectly normally and doesn't give me the complimentary slight shudder as the RPM doesn't do the whole dipping routine, which in turn obviously makes the car very pleasant to drive.
Have tried everything including having the garage clean the throttle body, changed the Idle Air Control Valve (twice by the way), checked for vacuum leaks (there are none to speak of). At this point I am irritated and close to fed up, and fast running out of cash and options!
By the way the problem has drawn codes which I rather foolishly had taken off.
If it helps any, the car used to do something similar even with the air conditioning off, but with all the cleaning, changing of the IACV, and a slight tune up from a noticeably lower 500 RPM to the usual RPM of 650, the car drives well under non-AC conditions. It now reserves its intermittent misbehaving to when I'm trying to cool off.
Please don't suggest not using the AC, as I live in the tropics of Africa to where the car was imported from New Jersey. Trust me, I need this problem solved, and my AC working.
Please help...

 

I see one or two people have checked this thread, but is it possible that a kind soul would please consider helping out...pretty please?...thanks...

 

Your symptoms suggest idle air control problem. Since valve was replaced, the problem may be 1) dirty blocked idle air passage (remove valve and be sure passage is clean and open) and/or 2) dirty, sticky throttle plate (clean both sides of throttle plate). Cleaner is throttle body cleaner.

good luck

 

It could also be incorrectly set base idle. If you've tried adjusting the working idle, the IACV will try to compensate, but won't be able to do a good job with extra loads like AC.

 

Thanks ever so much for the suggestions. However you are talking to the least mechanically minded car owner in all of the northern hemisphere, so I'm afraid I'm going to have to ask you to talk S-L-O-W...so here goes...where is the throttle plate located so that I can try cleaning it? And secondly, if I can't lay my hands on a throttle body cleaner, what would be an equally effective and more readily available alternative? Thanks again...

 

Thanks for the suggestion, but would like to know what the correct base idle setting should be, or how one can be sure whether the setting I currently have for the base idle is correct or not.

 

The throttle plate is attached to throttle actuation mechanism at the entrance to the throttle body. You have to remove the air intake duct to perform the cleaning. Manually force the throttle plate open and spray throttle body cleaner on both sides of throttle plate. Use an old tooth brush or parts brush to clean both side of throttle plate and bore around the plate. Back of plate is usually heaviest accumulation.

I would also clean the IACV passages on either side of throttle plate, and remove IACV to allow cleaner to be forced through the passages.

Once this is done, a base idle setting may be indicated. Remove IACV electrical connection and adjust idle air bleed screw on top center of throttle body entrance to obtain 700+/- 50 rpm. Check engine light (CEL) will come on due to disconnected IACV. Pull BackUp fuse in underhood fuse box for 20 secs to reset ECU and turn off CEL.

There is a 91 or 92 Accord Service Manual for download from links on this site. It should be a big help.

good luck

 

Here's a picture of the throttle-body (#5). Follow the big black rubber tube from the air filter housing over to this thing.

The throttle-plate is inside the throttle-body, it's a plate that opens & closes to let air into the engine. Clean it with solvent (throttlebody cleaner or carburator cleaner) & an old toothbrush. It collects black muddy crud around where the butterfly closes against the bore.

There's a cable from the gas pedal to the throttle body, make sure it goes a bit slack when the gas pedal is not pressed.

The idle-air adjustment screw is #1.
The IACV is #9.

Base idle procedure:

- Get the engine warmed up completely. Turn off ALL loads like AC, blowers, stereos, EVERYTHING.

- Unplug the wire from the IACV. The engine will want to stall, so nurse it with the throttle while you adjust the idle-air screw. I think you want 550 or 600 RPM, not 700.

- Turn it off, plug everything back in, let it cool down completely.

- Reset the ECU by disconnecting the battery or by pulling the #13 fuse in the right-dashboard fusebox (near the right-side door hinges) for a minute or 2.

- Start the engine without touching the gas pedal. Let it warm up completely without touching the gas pedal.

 

Thanks

 

Thanks. Was looking for the links to the pictures in your post marked #1,#5 etc.? Can't see pictures or links. I'm sure I'm the one not doing something correctly, but if not perhaps you could re-post? Again, I appreciate all the help...