I just bought a 1989 camaro rs with a swapped in 5.7 and 5 speed. The car has headers, and a custom exhaust, the problem im having is it runs very poor, with a hesitation and stumble. I replaced the map sensor, I was getting codes 33 & 45, this cleared the codes. The car still ran horrible, I disconnected the temp sensor to force into open loop and this somewhat cured my problem, it no longer hesitates and stumbles, but still occasionally stumbles and has a serious lack of power. The motor supposedly came out of a 90 truck, it does appear that they swapped out the 747 ecm from the truck to the car. Tomorrow I plan on checking the TPS and IAC. Does anyone have any thoughts on what the issues may be?

 

Also am getting a code 24 which I assume is unrelated

 

I would STRONGLY suggest finding out what the fuel pressure is while the engine is running. If you do not know the fuel pressure is appropriate you could spend lots of time and money on buying parts you probably will not need.

 

the 305 it probably came with had a fuel pump enough to feed it, but not the 350

 

Im going to pick up a 0-15psi gauge tomorrow, I assume I should put it in the fuel rail before the TBI unit, it will be mounted under the hood, not in the passenger compartment.

 

Ummm here's a good question, was the car tuned? That could be your problem. Switching from a 305/auto to a 350/t5 without changing the computer/chip is going to cause a mess of problems.

 

LIke I said earlier I have only had the car a few days, however it does look like they swapped the 747 ecm out of the truck into the car, I decided to check a few other things this morning, I checked the cts and got a reading of 3.5K ohms with ignition on and engine not running, and 3.6 volts at the yellow lead. Does anyone know what size/type fittings the fuel rail hard lines use so I can pick up some hardware to plumb in the fuel pressure gauge?

 

Somewhere I saw a thread that discussed a 0-30 PSI fuel meter someone had mounted with a T fitting and high pressure hose clamps. He mounted it in the rubber flex line that couples the hard lines on the driver's side in the area behind the headlights. Looked like a neat installation and it was probably not much work. I think he specified the part numbers he used. Cannot remember if he spec'd JEGS or SUMMIT RACING part numbers. Use the 'Search this Forum' tool but I am not sure what forum it was in.

Here is one such thread:
https://www.thirdgen.org/forums/tbi/...ressure+clamps

 

SO I installed the pressure gauge, im getting a consistent 11 psi, unrelated question should the voltage on the cts drop or increase as the temp goes up?

 

Here is what I would do to find out if the coolant temperature sensor is working.

When the engine is cool unplug the sensor and measure the resistance of the sensor. Then plug the sensor back into the harness.

It is my understanding that at low coolant temperatures the resistance is quite high (in the 5 or 10 thousand ohm range).

At high coolant temperatures I believe the resistance is very low (like 200 ohms when temperature is about 220 degrees F). Since I do not know what type of 'voltage regulation' system is being used across that sensor I would suggest getting the engine hot, shut it off, then unplug the coolant temperature sensor and measure the resistance of the sensor.

Then remember to plug the sensor back into the harness.

That circuit might hold the voltage 'constant' and yet monitor the changing 'current' within the circuit.