Ok so heres the deal, I have a 93 Civic Hatch with a JDM B16A engine in it.

My car runs fine, but whenever I put in the clutch the revs will drop down to 750rpm then fluctuate up and down from 750 to 1500rpm for about 10 secs then finnaly drop back down to 750rpm. And if my car is still moving and I put in the clutch the revs will stay at about 1200 rpm till I come to a complete stop then they will go back to the reving up and down from 750 to 1500 rpms thing. Also if my car is sitting at a red light just idleing, and then I rev it in neutral it will do the weird reving thing again.

I just would like to know of anything and everything I can check for to solve this. Any help would be appreciated.

 

well i did the same thing and it happened the same too. i sold my car though and the other guy who bought it said that the timing was off a little. thats all what he told me so check your timing.

 

Check out the distributor real good, it can throw off the timing and mess up your idle.

 

Check for what?

 

my b16 is doing the same thing, I checked vacum lines, tps, map, iat i give up. when its doing that, if i put my headlights, rear defroster, and heater on and press the up on the windows it'll drop down and will be fine after that, until the next stop

 

mine did that for a while too turns out it was just air bubbles in the coolant..try bleeding it

 

Any chance you have a link to a how to page? Or can anyone tell me how to do it. Thanks.

 

does it do it only when warm? or all the time? where is your idle at cold start up?

ok when it's doing it pull the IACV wire plug off does it stall? should just drop idle not stall. if that checks out ok replace cold start valve.

 

Yeah, it will only do it when warmed up.

 

mine does the same thing....it'll idle up to like 1500-1800rpm then I just tap on the gas a little and then it drops back down...don't know what it is...

 

Check vacuum lines and reset your ecu first since thats the easiest, have you altered or moved the TPS lately?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by JDM-Vic &raquo;</TD></TR><TR><TD CLASS="quote">Yeah, it will only do it when warmed up. </TD></TR></TABLE>

what RPM is your idle at cold start up?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Xsi &raquo;</TD></TR><TR><TD CLASS="quote">Check vacuum lines and reset your ecu first since thats the easiest, have you altered or moved the TPS lately?</TD></TR></TABLE>

actually yes I have....I swapped out intake manifolds and it has done it ever since. I put on the AEBS intake manifold....

 

about 1800rpm

 

my car was doing something similar recently. my problem was the EACV, Electronic Air Control Valve. it's on the back of the intake mani with two coolant lines and a small wire harness going into it. i pulled it off and sprayed it inside real good with brake cleaner. some gunk came out, and soon it was looking pretty clean. bolt it back on, and i now have a rock solid idle! i'm so happy~

btw, no need to open up the coolant area of the valve, there's nothing in there to clean.

hth,
jeff

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Bulldogg83 &raquo;</TD></TR><TR><TD CLASS="quote">

actually yes I have....I swapped out intake manifolds and it has done it ever since. I put on the AEBS intake manifold....</TD></TR></TABLE>

The TPS causes a lot of idle problems if not set correctly. You need to use a voltmeter to ste the TPS to the correct voltage when the throttle is closed. Do a search to find the right voltage for your car, probably around 0.45V