EJ8VTEC

The other day when I started my car the AC was already turned on. The engine was not warmed up yet (it was in the afternoon and I was leaving work). A couple second after the car was started, the idle jumped up and down a few times . Occasionally the idle does fluctuate or stick high (im assuming due to the iacv) so I didnt think much of it and turned the AC compressor of. When I turned off the AC it started idling normal so I assumed it had something to do with the iacv and praying there was nothing wrong with the ac unit or anything like that.

When I went to work this morning it didnt happed at all/ didnt use the AC.

Today when I got into my car after work it did it again. I DID NOT have the AC on at all today, and since it was a little cooler today the engine took a few more minutes to warm up fully. As I was pulling out of the parking lot (car was still not fully warmed up, but pretty damn close) I pulled away and the RPMs broke up slightly, similar to a missfire but the CEL wasnt on nor did it flash on at all as it happened. At the light I was thinking I should pull over when I make the turn but as I was sitting there and the car fully warmed up it ran 100% fine.

Just very weird to me.


Anyone have any ideas?

EJ8VTEC

its an obd2 b16

slowcivic2k

Unbolt the IACV and spray some brake parts cleaner in there if it is filthy, also service your PCV valve and make sure it is operational. if the operation of one of these is intermittent, it will demand more from the other until the other one unsticks and allows air to pass.

The PCM should step up the idle by 100-150RPM when the compressor is on, and that is done by increasing the duty cycle of the IACV to allow more air while it is running, since this puts drag on the engine.

EJ8VTEC

ok, ill do that.

So, you think its strictly the iacv/pcv correct?

slowcivic2k

Not strictly, it could be any type of airflow issue, a vacuum leak perhaps that is only partial (like a leak clogged and unclogged by carbon) but those are the two most probable systems to check, because they dictate idle speed directly. Even if you had a small vacuum leak, the IACV would correct that by closing more, to compensate.

EJ8VTEC

yeah ill have to check that... This morning the same thing happened...

When I started the car, everything was fine, so I turned on the AC to see what would happen... Same thing, ran horrible and then the CEL came on... So now I can run the diag and see what the CEL is on for to narrow it down. Im actually kinda happy about that...

We'll see what happends when I run a diag tonight...

EJ8VTEC

Well I ran a diag an there is a missfire code for cyl 3... Ill have to check it out later tonight....

EJ8VTEC

Turns out 3 out of the 4 spark plug wells were half filled with oil.....

I know this is a vavle cover gasket and spark plug gasket issue... there any chance of anything else causing this or that would be the only reason?


Modified by EJ8VTEC at 7:04 PM 7/12/2007


Modified by EJ8VTEC at 7:05 PM 7/12/2007