A couple days ago my ZC started idling funny. It USED to be at ~750 but just recently started dropping then rising up again (~450-800). It happens to an even greater degree when I've got the brake lights on or some other electrical drain (almost stalling).

Alternator maybe? Battery? Grounds?

I also noticed that every now and then it would jump up to around 1200rpm's at idle. A worn timing belt wouldn't cause this, would it? I'm gonna try to get my alternator tested at autozone or something to see if it's really that...

My mods are: ZC motor, CRX Si trans, Exedy OEM clutch, ACT lightweight flywheel, Fresh tuneup with ~750 miles on it, DC **** header, RS*R Exmag exhaust, stock cat (probably clogged).

Like I said it just started happening in the past few days... I haven't even changed anything to cause that.

 

check the tps

 

Any engine codes?
sounds like a idle air control valve prob

 

Yup my iacv always acts up and i even put a dif one in and it still needs cleaning sometimes..

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by nummbr7 &raquo;</TD></TR><TR><TD CLASS="quote">Any engine codes?
sounds like a idle air control valve prob</TD></TR></TABLE>

Nope, no engine codes. Can the IACV just go bad instantly like that, or is it more of a gradual thing?

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by CRX_Control &raquo;</TD></TR><TR><TD CLASS="quote">check the tps</TD></TR></TABLE>

It's supposed to be .5v at closed throttle and 4.5v at WOT right? I will check it out this weekend.


This really sucks because it's hard to drive when everytime I stop, the idle drops and feels like its gonna stall out... Then it'll go back up to normal. Couple seconds later it'll do it again.

Any ideas about when there is any kind of electrical drain? Sometimes if I'm sitting at a light and I take my foot off the brake the idle will go up ~100-200rpms ... same with if I turn the headlights on and off. I know it'll vary the engine speed slightly but not to that degree. Should I check the alternator and battery? I have no idea how old that battery is and the alternator is whatever was on the ZC when I bought it.

Thanks for the help guys Keep the ideas coming!

 

https://honda-tech.com/zerothread?id=343980

^^ try that out.