delancj

I have a problem with idle surging in an 89 iroc, 350, auto, .500 exaust duration, k&n, Flowmaster exaust, edelbrock headers, 160 deg thermostat, 10:1 compression, 88 L98 corvette heads.

I have replaced the maf, iac, o2, tps, and it has checked negative for vaccum leaks. Happens only at idle, closed loop, after the engine temp is above about 160F



Here is a datamaster-32 log. 89 Fbody auto.

the idle with the surging starts at 03:07:00
exaust smells rich too.
Someone asked where can i get data master?

http://www.ttspowersystems.com/DM_Software.htm

Thanks,
JD

delancj

I think i've figured it out myself. O2 is getting too cold being where it is located in the headers so its not reading anything under 1250 RPM. short and long term go to 25+%. too rich to idle, almost dies, the computer leans it a little and thats where you get the surge.

I know there are lot of other people with this problem that i have found while doing research so hopefully this will guide someone in the right direction.

Cure to the problem:

hook up a 3wire heated O2 insted of the one wire.

-peace
jd