S13 cold start problem

[beaverbeliever07]

I recently purchased a 89 fastback, i love my car to death but it had a few problems when i purchased it. It backfired, idled really rough and when it was started up, it would bounce around from 400 to 500 RPM's for a few second until it died. To get the car to start up I had to give it some gas to keep the RPM's up for a few minutes before it would idle on it's own. I took it to the local preformance shop and they fixed the timing, changed an injector out and recallibrated all sensors. I took it out and it fixed the rough idle problem and the backfiring problem.

Unfortunately the cold start problem persists. Now though, the RPM's hover at 1500 for the first 10 seconds after startup, THEN drop down to 400. What could be wrong here!!!!

[s13sr20chris]

1500 on cold startup is ok. the 400 is too low. i would ask them if they set the idle as well. if not ask them to do that or you could just turn up the idle screw.

[beaverbeliever07]

I know that during the warmup cycle the RPM's should hover around 1500.......but i'm wondering why it's dropping to 400 after 10-15 seconds.........

[s13sr20chris]

yeah, that is wierd. is it running rich or misfiring at that time?

[beaverbeliever07]

Nope, it doesn't backfire during the warmup time.........i'm stumped.

[s13sr20chris]

yes, but does it smell of fuel out of the exhaust? you could try removing and cleaning you iac=aac. those are the valves controlling your idle.