My 1986 iroc starts fine but it will not stay idleing when it is cold.I have to keep my foot on the accelerator a bit to keep it going. Once its a bit warm it idles all day long. Would the cold start (9th injector) have something to do with this? How long does the 9th injector inject fuel to keep the car idleing when cold? Thanks

Sounds like your cold start is not working. That is exactly the symptoms I had on my TPI install without the Cold Start injector on an '86 system. Could be your CS injector, or your cold start switch. Cold start injectors are no longer available, but they can sometimes be rebuilt. Cold start switches are a little expensive, but available IIRC.

I opted to put in a cold start delete plug ( Ebay) and reprogram the ECM to later code that uses all 8 injectors for cold start. Works perfectly. Cost of going this way is probably a wash, or maybe even cheaper, than getting the cold start valve and/or switch. You can even buy the reprogramed chip on Ebay ( Search TPI Prom).

HTH

Beofre replacing parts and such, I'd suggest you get a scan tool and monitor some things.

If it starts up fine, then initially I'd think the CSI is operating correctly...but of course as previously posted, the thermal switch could be bad and shutting off extra fuel...that said, seems to me you need more air in the engine..(reason why you need to keep the throttle blades open)...which could indicate the IAC isn't working properly. This could be something as simple as the CTS not right, or more expensive like a bad IAC.

Regardless, your best investment would be a scan tool, I believe there's a few free/cheap versions that can be had via dowloads and software for a laptop, instead of buying a 200 dollar tool.

Good luck

Thanks for the input guys. I will try all the above with little or no investment. My friend has a Good scan tool that i can borrow. Maybe its just a wire that not plugged in very well. i do appreciate everything. I basically needed to know if thtas what could be the problem or it might be something else. thanks again. Ill Post when i figure it all out. Mike

Check the crank fuse.

If it ends up being your cold start injector and you need one I have one
Ill give it to you for free just pay shipping

but be warned I can not guarantee it works
I needed some 22lbers to hold me off until I could afford better ones so I bought a fuel rail off an 87 L98 with all nine injectors on it and I have an 89 which doesnt have the 9th injector
so far all the other injectors work perfect and if you know how to check if it works (like if a normal ohm test will work) i can try to check it for you but I figured Id offer cuz I have no use for it

send me a PM if interested

What did you end up finding on this?