Car won’t start and idle after fast install
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Joined: Aug 2006
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From: Hamlin ny
Car won’t start and idle after fast install Hey guys so I just got done doing a fast 92 install with a speed engineering 92mm throttle body, still using stock maf and slp lid. Went to start the car and it won’t start and idle and cel came on for p0122 throttle position sensor, so I switched out the tps that came with the throttle body to my old one and still the same thing is happening and cel comes back for the same code. Checked all vacuum lines and made sure to torque bolts down in sequence and to spec Any ideas on what else to look for? Or anything I might need to do adjust on the throttle body? Or is it just as simple as needing a tune, just concerns me having that tps code coming up.
that code is for the tps sensor voltage signal. u need to see what the signal is reading on a scan tool or hp tuners etc. most likely the sensor or throttle blade needs adjusting to be within gm spec. if you provide me with the year make and model I can get u those specifications and a procedure for checking the sensor and adjusting.
Thread Starter
TECH Enthusiast
Joined: Aug 2006
Posts: 734
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From: Hamlin ny
that code is for the tps sensor voltage signal. u need to see what the signal is reading on a scan tool or hp tuners etc. most likely the sensor or throttle blade needs adjusting to be within gm spec. if you provide me with the year make and model I can get u those specifications and a procedure for checking the sensor and adjusting.
2000 z28, the engine however is a 2000 lq4 block out of a Silverado, and it’s a fast 92 intake with a 92mm speed engineering throttle body, the maf I’m using is still stock 78mm but I have an 85mm truck maf that I will be putting on. My goal is to at least get it running and somewhat drivable to have the tuner get everything else sorted out.
Thread Starter
TECH Enthusiast
Joined: Aug 2006
Posts: 734
Likes: 2
From: Hamlin ny
So I was able to get the car started by adjusting idle screw on throttle body we had good vacuum so no leaks and got it to idle ok but when you shut the car off and turn it back on it always shoots up to 2000rpm then idle backs down slowly, and if you blip the throttle it will stay at high idle and go back down slowly, we had hp tuners hooked up and the iac for whatever reason was reading 0 when car was fully warmed up. Then started reading around 35-45. It is the iac that came with the speed engineering throttle body not my stock one so not sure if that’s the issue
