Hey guys I have a strange problem with my 90 GTA.

The first start of the day my car takes a while to start and then idles up and down but once its warmed up it runs great and every other start of the day is fine and it instantly falls into a normal idle.

I have replaced the cap, coil, rotor, ignition module, wires, plugs and injectors.

Heres a video of a cold start.
http://www.youtube.com/watch?v=JTVEMEJpgfw

Heres a video 2 hours later.
http://www.youtube.com/watch?v=J9UhCg-a5C4

 

Hello Pontiac400!!

Have you cleaned up your IAC valve lately???

If not, give it a try, sounds like it's sticking!!



Be careful when you clean it with any solvents, don't immerse it in a parts cleaner, but rather just clean up the pintle end really good!!

Should do the trick!!



Second item to try is the EGR valve, is it sticking????

Any code 32???

 

the puff of white makes me think you may have a leaky injector or fpr is leaking somehow.like its flooded.See how fast the pressure goes down after you cut it of with a fuel pressure gauge hooked up to the fuel rail.Have you checked to see if your IAT AND TPS are adjusted properly?

 

Have you tried the Idle Air Control Valve? To test, remove the valve itself, plug it back in, and turn the ignition to "on" setting. It should move in and out freely. If it doesn't, sounds like thats the culprit. Possible the valve is sticking and doesn't want to move when cold.

What other mods are on the chip? Any emissions delete?

 

Ha, I was in the middle of typing my reply when these two did. Go figure.

 

Thanks guys IAC valve is what I was thinking but I didn't know if it could act like that at first then be fine. I will check and clean it tomorrow.

It has new injectors and fpr. I will check pressure tomorrow.

There are no codes showing up and there is no EGR its tuned out but all the other emissions equipment is still there.

Thanks again for the suggestions I will report back when I check every thing.

 

I would try the IAC first. Seeing as how you've done a Throttle Body Coolant Bypass, there is no longer a boundary of coolant nearby to keep the valve from freezing up and sticking. As stated above, remove the valve, plug the wires back in to it, and turn ignition on and see if it moves freely.

 

Hey guys I checked and cleaned the IAC it had a small amount of carbon on the pintel face and a little more on the spring It seemed to help a little but I think I might just replace it and see if that helps.

I checked the fuel pressure at idle with vacum unplugged and it was 44psi With the ignition off it held 42psi for the 3 hours I watched it.

I got the car Inspected today for the first time since 2007(its been at the body shop for 2 years) and with no EGR (removed from tune) it PASSED. So it seems to be running good other than this.

Heres the Inspection results.
LOW SPEED (15MPH)(1305RPM)
STANDARD READING
HC(PPM) 148 131 PASS
CO(%) 0.83 0.41 PASS
CO2(%) 13.50
O2(%) 1.70
NOx(PPM) 1110 958 PASS
DILUTION(%) >6 13.90


HI SPEED (25MPH)(1280RPM)
STANDARD READING
HC(PPM) 144 116 PASS
CO(%) 0.92 0.41 PASS
CO2(%) 13.50
O2(%) 1.40
NOx(PPM) 1014 778 PASS
DILUTION(%) >6 13.90