i have a 99 b18c1 , and just recently it started ideling funny, goes down to zero and bumps back up to 500rpms, i had it in a shop and they told me that it was a vaccum leak, said they fixed it, drove it down the road and my CEL came on...again, replaced the IAC with one off a LS motor....not sure if that could be an issue, along with this whole mess, vtec wont kick over...it started all of this about 5 days ago...i'm stumped....i'll take any advice

 

could be a vacuum leak still, or maybe coolant leak so you're getting air into the lines?

Have you checked all your vacuum and coolant lines? If they all check out I'd try bleeding the cooling system.

 

i was thinking about that, i didnt bleed the coolant system after putting the new IAC on the car, we couldnt find a vaccum leak at the shop...but they also didnt wanna do much with the car because it was swapped, could not bleeding the coolant system pose this kinda problem that i'm having?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by dchatch &raquo;</TD></TR><TR><TD CLASS="quote">i was thinking about that, i didnt bleed the coolant system after putting the new IAC on the car, we couldnt find a vaccum leak at the shop...but they also didnt wanna do much with the car because it was swapped, could not bleeding the coolant system pose this kinda problem that i'm having?</TD></TR></TABLE>
yes.

If you take coolant lines off and don't bleed the system you're 99% likely to have an air bubble trapped. It gets moved around just like the coolant but it's not the same temp as the coolant ever so when it hits the various sensors you get funky wavering idle.

You can either use the bleeder valve bolt thing or just raise the front of the car and let it warm all the way with the radiator cap off (fan must come on). Try that and let us know if it helped.

 

bled the coolant system + cleaned the throttel body, still ideling the same it did....only does it when its warm or been running for awhile, i'm stuck....also need help with getting vtec back...small probs hurting my head...

 

FIT valve on the mani is loose, thats causing
your jumpig idle.

 

Valve inside Idle Air Control Valve loose, take it off, tighten the plastic screw, mine always goes lose. I think its the big rectangle thing on the throttle body. Another problem could be ecu isn't tuned. Lastly, your map sensor could be dead, causing the bumpy idle, signs of this happens when your idle is really high, and only drops after hard use

 

map sensor is fine, just replaced that last week, the car will idle bad for a few minutes then idle fine....this is a new development since i bled the cooling system, it only dose this after the car warms up never when cold after i bled the cooling system... i'm throwing codes 7 and 14 (TPS and IACV), but the IACV has been replaced...could a bad TPS be the culprit?

 

try adjusting the tps first then reset the ecu.

 

i get in the car to drive it today, and after driving it for about an hour i realized the ideling problem had gone away, vtec had started crossing over again, and my VSS was working...no CEL, car ran perfect...the only thing i did to the car was check the connection at the knock sensor...wasn't plugged in all the way, it rained a lot all day and temp dropped considerably....leaving me scratching my head

 

so i got everything in order..turned out to be a bad engine harness...loose wires had come out of the clips connecting to the ecu..causing me all sorts of trouble, my car still surges when cold...could this be the FITV? i know sometimes that little screw will back itsself out and cause problems....but i was wondering if there could be anything else that might cause the motor to do this....only in the morning