odd idle problems

jdmspecdc5 · Post by **jdmspecdc5** » Mon Apr 10, 2006 9:57 am

my cal has been working great for me until just recently. nothing mechanical has been changed but the idle is somewhat screwed up. in the morning or anytime for that matter when i start the car up after it's been sitting the idle will first start in the high 13s then gradually make its way up to 14.7. the car idles at 14.7 for a few seconds then starts to lean out to about 17. none of the ect or iat comp values have been changed so i'm just wondering what could be the cause of this. even when adding fuel the a/f does not change and switching to open loop makes the idle surge.

TurboLS · Post by **TurboLS** » Thu Apr 27, 2006 6:56 am

i notice similar issues, although my car never goes really lean when idling. One thing to keep in mind is that when running in open loop (as far as I know), the ECU does not account for changes in temperature which is why if you have a map that is tuned for one temp (say 70F IAT) and you get in your car the next morning and it's 50F out, you'll be running way rich across the board, including idle. The idle will surge because I think the IACV is trying to compensate to give the correct idle rpm while the ECU is trying to get the correct lambda value at that load and rpm.

Post by **Spunkster** » Thu Apr 27, 2006 9:29 am

This sounds more like a wideband wiring problem. check to make sure that no wires are crimpted or bare and grounding out. Your sensor may also be going out.

TurboLS · Post by **TurboLS** » Thu Apr 27, 2006 10:33 am

Spunkster wrote:This sounds more like a wideband wiring problem. check to make sure that no wires are crimpted or bare and grounding out. Your sensor may also be going out.

Are you responding to me, the original poster, or both>?

thanks.

Post by **Spunkster** » Thu Apr 27, 2006 1:43 pm

yes :)