Howdy all and thanks for the help ahead of time.
I have purchased and installed a TPI motor into my 78 Scout but am having that damndest time getting t to run right. Heres what I purchased/what I know about the motor.
It was pulled from a 92 Firebird.
It has a 350 lower end but I was not able to verify it came from the original vehicle.
I have a ron francis wiring kit with a telorvek box.
I installed a vats bypass.
It has a manual oil press switch and no parking signal.
I have replaced the IAC, TPS plugs, wires, cap & rotor.
I replaced the knock with a stock 350 sensor.
-Heres the problem
It runs fine for a minute then the idle lowers and it starts running like crap, like its missing at idle.
I have read up on this and have a few ideas but wanted to bounce them off the pros.
1) It has ecm from a 305 and its not getting the right mixture once the iac closses.
2) The knock sensor is giving the wrong info and is setting limp mode.
3) 305 injectors on a 350 arent cutting it.

Any input would be great, I love the engine and would hate to scrap it and buy a vortec if I dont have to.
Again, thank you.

 

ECM needs a prom for a 350 and change those injectors to 22lbers. That's mandatory with a 350 swap. When that's done, if you still have a problem call for pro's again.

 

Or at least learn to tune your ECM. tell it to feed a 350 and let it know you have 19lb injectors. It will run but wont be near as powerful at higher rpms.

I ran a 350 tbi engine with 350 injectors and a 305 ecm for about a week or two. It ran okay but not acceptable for a daily driver.

After all that, your knock sensor (or rather the knock it is sensing!) may be an issue too. Im not sure on the specifics here but your compression ratio could be through the roof causing the knock sensor, which kicks in after a bit, to make the engine run like crap. The ECM thinking its only feeding 305 cubic inches will make a lean condition and the knock even worse.

Youve got alot going on here. Do some research on tuning, cost of tuning, cost of ecm, data logging, cost of injector swap, what heads you have, pistons, etc. try to figure out where you want to go with this and how to get there THEN make a move.