TurboEM1

iTrader: (1)

Hey guys I am looking for some input.

Car: 1991 CRX Si
Engine: OBD0 B16a, PW0 ECU, no check engine lights, everything wired good. Car runs fine except....

Idle when its cold out. This problem started when the temps dropped. In the summer/spring/fall its fine.

When the temp drops this is what happens. The car starts up fine but goes up to like 2000rpm then 500rpm then 2000rpm then 500rpm and it keeps doing that. The car revs up to 2000rpm then a sensor must see the idle is to high and cuts it, when it drops to 500rpm it must sense its to low and starts the process again. Sometimes it drops so fast it will not catch itself and the car will stall. If I hit the gas a hold it at like 1500rpm for a minute or two and let it warm up a little bit it will then idle fine.

Any ideas?

Thanks

da6jdmteg

check the little thing by the throttle body that has the little stem coming down to where the throttle cable connects. also check for vacuum leaks. and gasket leaks. that could act up in the cold.

TurboEM1

iTrader: (1)

I was thinking it sounds like a vacuum leak but would that only happen in the cold?

hybridef

does sound like a vacuum leak, but would it jump 1500rpm? im not really sure if the cold would play a factor in this. I had clearance issues with my zc on the stock hood, so every now and then id have to replace a vacuum line. Did the same ****, but only jumped about 1000rpm

TurboEM1

iTrader: (1)

it only does it in the cold. I had the engine in for about 5 months and never had a probelm. now when the temps dropped it happens. On warm days it stops. It is definately temp related.

tcgordy

mine done the same thing, and my icv wasnt plugged in. fixed it and perfect now.

jakscivic

Surging is usually the IACV in back of your intake manifold. It might not be pluged it, but then you would be throwing a CEL. So what you should do is go buy some brake clean and unbolt the IACV, its real easy, just two 10mm bolts. Then spray the screen in there hella with the brake clean and let it dry out a bit. Then bolt it back in and see if that works.

.Manny.

iTrader: (1)

my IACV was causing that on my b16. i cleaned it but it still did the same thing. so i just replaced it and everything worked out fine.

jakscivic

yeah, that can also be the problem, your iacv might just be broken. I replaced mine as well, but it wasnt broken, doh. Oh well, I got it cheap. And its brand new OE and it looks good on my new skunk2 inatake mani.

13g-crx

Stupid question but have you checked your coolant level? It caused the same thing with my z6 once.

TurboEM1

iTrader: (1)

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by 13g-crx &raquo;</TD></TR><TR><TD CLASS="quote">Stupid question but have you checked your coolant level? It caused the same thing with my z6 once.</TD></TR></TABLE>

Yea my coolant level is good.

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by jakscivic &raquo;</TD></TR><TR><TD CLASS="quote">your iacv might just be broken. I replaced mine as well, but it wasnt broken, doh. Oh well, I got it cheap. And its brand new OE and it looks good on my new skunk2 inatake mani.</TD></TR></TABLE>

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by 90_EF_Si &raquo;</TD></TR><TR><TD CLASS="quote">my IACV was causing that on my b16. i cleaned it but it still did the same thing. so i just replaced it and everything worked out fine.</TD></TR></TABLE>

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by jakscivic &raquo;</TD></TR><TR><TD CLASS="quote">Surging is usually the IACV in back of your intake manifold. It might not be pluged it, but then you would be throwing a CEL. So what you should do is go buy some brake clean and unbolt the IACV, its real easy, just two 10mm bolts. Then spray the screen in there hella with the brake clean and let it dry out a bit. Then bolt it back in and see if that works.</TD></TR></TABLE>

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by tcgordy &raquo;</TD></TR><TR><TD CLASS="quote">mine done the same thing, and my icv wasnt plugged in. fixed it and perfect now.</TD></TR></TABLE>

OK. A lot of you are saying IACV. The engine is a OBD0 JDM B16a. Does it have an IACV or is it like a FITV?

Any pictures of where it is on the engine or what it looks like? How much are they new?

Thanks