ok i have a b20vtec with 11.5 compression ITR IM and TB. my question is i cant get the car to idle down. what it does is when you first start it when its cold it would go to 2000rpms then work down to about 1400rpms after a good while it would start to lope from 1400 to 2000rpm. i have changed TPSs and adjusted the idle screw still nothing. does this have to do with my compression? if not what could it be? i know my IACV has very little miles along with my ITR IM and TB.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by NA CRX Si &raquo;</TD></TR><TR><TD CLASS="quote">ok i have a b20vtec with 11.5 compression ITR IM and TB. my question is i cant get the car to idle down. what it does is when you first start it when its cold it would go to 2000rpms then work down to about 1400rpms after a good while it would start to lope from 1400 to 2000rpm. i have changed TPSs and adjusted the idle screw still nothing. does this have to do with my compression? if not what could it be? i know my IACV has very little miles along with my ITR IM and TB.</TD></TR></TABLE>

You could try adjusting the screw on throttle body. Maybe the trottle body is not closing all the way. Are you adjusting the idle screw on the throttle body after the car has warmed up?

 

yeah i adjusted it both ways and nothing. does it have anything to do with my compression being on the high side?

 

Try loosening your throttle cable, that will bring it down some. Id bring it down to about 600 warm idle with the cable then tighten the screw to bring it back up to the 750 range.

 

Compression has very little effect on the idle. When you replaced the TPS did you set it to 0.45 volts at idle? If the TPS is not set properly, the ECU will think that the throttle is open. Not a bad idea to check the throttle cable tightness as stated above, the cable can hold the throttle open.

 

yes i checked the cable also. i pretty much had the cable loose to make sure it wasnt pulling it back some. im running out of ideas guys. what could it be?????

 

With your engine warm and running, what happens after you unplug the IACV? The idle speed should drop to about 500rpm. This is referred to as the base idle speed. If it drops, but not enough, adjust the idle air bypass screw to lower it some more. This assumes that the throttle blade stop screw is set correctly as well. If you mess with this screw, you are also messing with the TPS output value. Once you've got the idle down low, cut the engine off, plug it back in, reset ECU, and start her back up.