Hey folks. Just got my lt1 swap started up. ( lt1 is from a 95 camaro and is now in my 91 )
Started pretty good but I found as I was test driving her that the warmer it got the higher the rpms went. After about 20 min the car wanted to run at 4000 rpm. I had to unplug the IAC to get it to stop. It's now running at 1500 rpm

It was from an automatic car but I swapped in a T56
Thanks in advance

 

I would start with making sure the coolant temperature sensor located in the water pump is fine, here is the chart for the resistance vs. temperature, you can also unplug the IACV before starting the engine, then see if the issue still happens, this can rule out the iacv control.

14 Deg F 16,180 Ohms
32 Deg F 9420 Ohms
50 Deg F 5670 Ohms
68 Deg F 3520 Ohms
86 Deg F 2238 Ohms
104 Deg F 1459 Ohms
122 Deg F 973 Ohms
140 Deg F 667 Ohms
158 Deg F 467 Ohms
176 Deg F 332 Ohms
194 Deg F 241 Ohms
212 Deg F 177 Ohms

 

Thanks for the reply. I'm going to check the resistance of that coolant temp sensor in the am. I did unplug the Iac the rpm stopped shooting through the roof so at least I can drive it. I have to give it some gas to get it to start

Oh I have open headers and no O2s right now. She's going in for exhaust mid week. Can this cause it?

 

That shouldnt cause it, the cts is a very good possibility.

 

Funny thing is I caught the issue. For some reason when I drive the car the throttle bracket starts hanging up. It's a 58 mm. I compared the spring return tension on this one compared to a stock one. There is an obvious difference in spring tension. The stock one is much tighter.
Is there any way to adjust the tension?

 

Also I ohmed out the water pump coolant sensor and I only have 7.3ohms which doesn't make sense but I get the same 7.3 ohms on the iat. Same ambient temp

 

Tps is bad? 4000 rpm is a big deal, maybe a leaky injector?