OK, two main problems. Well, three.
1) My car doesn't idle right; the idle is different depending on time of day (temp/humidity doesn't seem to matter).
2) The car doesn't seem to want to run stoich; it usually sits at rich.
3) My next AirCare date is coming in 3 weeks (they use a sniffer to measure emissions while driving and at idle).

I'm not too worried about the driving test. It usually runs stoich while driving. But at idle, it almost always runs rich. I'm not sure if this is related to the wonky idle or not. Before I begin, it's an '88 CRX Si with a B16A (PR3 ECU).

OK, question #1 first - idle. It's messed, in short. Sometimes I'll start it and it will idle at 1000. Sometimes I'll start it and it'll idle at 750, then suddenly kick up to 1250. Sometimes it'll idle at 1250, or I'll start it and it will dip to 600, then go to 1250. However, the idle is usually stable at whatever rpm it chooses, though sometimes it will change almost randomly up or down (but never like a vacuum leak would). God only knows why.

Unplugging the IACV just now resulted in a CEL code 14 and no change in idle (it was at 1000). So I adjusted it down, trying to get to 500, and it started bouncing between 250 and 750. Left it alone and it stabilized at 750, running very rich. Again, God knows how it got the air to do that. Tapping the gas made it bounce around again until it stabilized, this time at 800. I tried to adjust it down to 500 until it died. I couldn't start it again - it kept stalling out.

With the IACV connected, while driving at night it usually idled at or near 750 rpm (before I touched with the idle screw today). During the day it would idle at whatever it wanted - between 750 rpm and 1250rpm. It would pick one and stick with that .

Oh, one side note: the IACV is from my old D16A6 - I tested it according to my Haynes manual before installing, and it checked out.

OK, problem #2: air/fuel. I figure that the idle air/fuel is messed because of the idle being messed. It was almost always idling stoich last night at 750rpm. But it doesn't *always* run stoich while driving, either, and if you sit in neutral and free-rev the engine to a set RPM level it won't run stoich (it'll sit at rich). However if you rev it in neutral and let off, so the air/fuel goes to full lean, and then get back on the gas, it will run stoich (and the rpm will dip/jump with the air/fuel ratio).

Fuel pressure is at 34psi with the engine off and the pump primed, and the pressure at idle (when the idle's adjusted to 750) is 30psi.

Can anyone figure this stuff out? My mileage is very crappy right now too and I think these problems are why (300-350km's per 30L).

P.S. I'm getting a lot of white smote at idle and while driving... it doesn't go away ever, just keeps coming... it has no real odour save burnt exhaust, and I'm don't see any coolant/oil consumption (I just checked, and I'm using Honda coolant & Royal Purple 5W30).

Picture of smote while idling:



[Modified by raene, 4:38 PM 12/22/2002]

 

Argh