Hey guys,

Need some help, I tried searching, but could not find a post with the symptoms I am experiencing

My bb6 prelude is having a problem with idleing, when the ac kicks on or if i turn the wheel while it is idling, the idle drops, as well as when I am sitting at a light, i will get a very low idle, when it does idle down, the ECU throws a cylinder 1 misfire as well as a random misfire code, the idle does not fluctuate too much, it just basically idles low when the engine sees a load

Here is what I have tried:

-Cleaned EGR Valve, has drastically improved the idle, but not enough to be in spec, car would stall before i cleaned the egr

-Cleaned IACV screen, basically just cleaned the carbon off the screen, did not seem to notice a difference

-New plugs and wires

- Unplugged IACV when car was running(recomended by service manual) - the idle drops but the motor does not stall and barely idles

Basically what I am hoping is that someone will be able to identify if my IACV is going bad, however, I am a little confused because it is not throwing a IACV code, it is throwing a misfire code

The reason i think it is the IACV is because the idle does not respond to load such as the ac, power steering or headlights

When i cleaned it, i just sprayed the screen and inside the IACV and put it back on, is there anything else i should have done while it was out?

Any ideas?

Any help is greatly appreciated

Thanks

 

If you want to incrrease your idle there's two ways. 1 there's that small screw mounted on the throttle body, if you have'nt messed with it there should be a small plastic cap you have to break in. 2 check your timing, in some cases if your timing is retarded your gonna have low idle.

 

Well i dont think its the idle setting, the reason why i am concerned is that, the engine idle does not respond to load, such as when i kick on the ac, the engine does not compensate for the extra load, which is why i think its the IACV

I guess i will check my timing

 

i have the same exact problem on my 94 vtec. by any chance do u have a lightened flywheel? if not try swapping ecu's with a buddy see if that helps.
http://cgi.ebay.com/ebaymotors...ZWD1V read the symptoms and try buying a brand new one and see if that helps.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by CRX A4 &raquo;</TD></TR><TR><TD CLASS="quote">I guess i will check my timing</TD></TR></TABLE>

It's worth a try, my motor is throwing a code for the
knock sensor which is retarding the timing.

It's ideling around 250 most of the time.

 

As far as I know, i have a stock flywheel, bought the car used so I have no idea whats in it

The other thing i noticed while looking through the service manual is that, this car has non-adjustable iginition timing? I havnt had a chance to check my timing but, if it is off, how would i correct the problem?

 

Update:

So here are the things that I have done so far to try to remedy the problem

- Changed Cap, Rotor, Plug wires, Plugs
-Cleaned IACV
-Cleaned EGR

The car runs considerably better than it did, but still idles low and throws code 71 and anothe random misfire code

However, whenever I am idleing, with the ac off, after a short period, the CEL begins to blink and the car thows the codes

I'm now wondering if i have a bad ecu?

Any ideas?

 

the CEL is blinking the code while the engine is runnning? I believe that that is supposed to happen only when the service connector is jumped, and you are not supposed to run the engine with it jumped

 

no, the CEL is not blinking the code, the jumper is not plugged in, the CEL is blinknig because according to the service manual, the ECU is detecting a condition that could potentially be harmful to the cat or something along those lines, basically a misfire

However, when the Light blinks, the engine is running smooth, so I dont understand

I'm beggining to think it is still the EGR causing the problem, I'm gonna try to clean it out again today

Any suggestions are appreciated

 

not sure about 5th gen preludes but 4th gen, to raise the idle, you unplug the IACV before starting the car, start the car, there's a screw near the top of the throttle body that you can screw in our out to control the idle. once you get the idle you want, turn the car off, plug back in the IACV, reset ecu.