My girlfriend's Accord (1999 4 cylinder LX sedan automatic) had a kind of slightly uneven/low idle and a P1667 check engine light code. As a first step, I decided to remove/clean the throttle body, which involved (in part) disconnecting the coolant hoses leading up to the throttle body, and spraying the throttle body with throttle body cleaner and scrubbing it with a toothbrush. I also sprayed inside the IACV a little bit and tried scrubbing it with a toothbrush briefly.

Anyhow, after reconnecting everything and starting the car up, now the engine surges wildly (1000-2300 rpm) in park/neutral, and feels like somebody is pushing the gas pedal when it's in gear. It seems to do it on a constant rhythm, maybe about once every second.

What the heck is going on? I have done a little research and think it COULD be that the coolant needs to be bled (I didn't do any bleeding), because there might be air stuck in the FITV (fast idle thermo valve). What do you guys think it might be?

Thanks so much!

 

Im having the same kind of trouble, when I first start it up it idles up and down. Its also shooting a P0170 code (burning fuel to rich) when I took it to the repair shop ther screws me sayin it was the map sensor and they replaced it. it went repaired for about 3 days and its back doing the same crap the idle is pulsing up and down and the fuel is burning real rich, I have no clue what it could be and any help would be greatly appreciated thanks very much

 

Any ideas anyone?

 

You may have introduced air into the system. There may be a bleeder valve on the thermostat housing that will allow trapped air to spit out. Google this term, zUpXgAJ1gjU. Watch the Youtube video on how to bleed air from the system.

The other thing I would do is reset the ECU. On your car, I would just disconnect the battery, because I don't know if there is a fuse you can pull to clear the ECU like on my old accord.

 

I NEED HELP!

I took off the throttle body again, and then proceeded to dig deeper by removing whatever the hell that big metal piece is behind the throttle body. I guess this is what the IACV is attached to (intake manifold, perhaps?). It's a little dirty inside but isn't anything that I would think would cause any problems.

Hopefully I can remember how to put everything back. I ended up damaging a hose and will need to replace it (I think it's a coolant hose, maybe an air hose).

What I noticed was that if I unplug the plug that connects to the side of the throttle body (blue), the engine idles smoothly, but high (2000 rpms). If I plug that in and run it without the throttle body plugged in (on top) the engine idles at a normal level (albeit a little rough) and doesn't fluctuate. However, if I plug in the blue connection (side of the throttle body) it fluctuates up and down, although at a lower set of RPMs.

Does this provide any hints as to what it might be? Please help because I am at wits end.

 

I tried bleeding the engine coolant using the bleeder screw, but this did not help the idling problem.

By the way! HINT! The car was completely cool when I started it today and there was no idling problem--for about 45 seconds. Then the problem began as normal. So it would make me believe that it only happens when the car is hot, which it tends to be... all the time.

 

http://www.2carpros.com/forum/automotive_pictures/99387_honda_95_1.jpg

From this diagram, it looks like the blue sensor I'm talking about is the MAP sensor, and the white one on "top" is the throttle position sensor. I suppose I ended up removing the intake manifold (top part of it) which has the IACV attached to it.

 

Helo ! try to read this post ! I think that your problem is the IAC.
Carlos.

Tutorial Limpieza y ajuste de FITV, EACV, etc. - Foros Hondaclub Argentina

 

I've seen this post somewhere before......Set the heat to max and bleed again. Did you resolve the CEL.

 

May have seen it on Honda Tech because I am running two similar threads.

I have set the heat to max and bled and it didn't solve the problem. I have not resolved the CEL either.

I am beyond the point where I cannot bleed the coolant because the throttle body/intake plenum are in pieces.