Swap Help

[bkn259]

Hey my name is Brian and I just joined your very nice forums. I have a 1994 1500 that had the stock 305 taken out and i just swapped a 350 that is punched .060 over with a small, mild cam in it out of a 95 1500 into it. I got it all running and put back together. Timed it correctly (disconnecting the timing signal from inside the cab) and it still runs like complete garbage. I know the motor runs fine because when i bought it i heard it start and run before i picked it up. i am running the stock tbi and stock everything else. It has new cap, rotor, wires, and plugs. I cant figure this out to save my life. any suggestions and help would be greatly appreciated. Thanks again.

[97chev1500]

Welcome To Fullsize Chevy Brian

Did you change the ECM when you swapped in the 350?It will not run right if you are using the stock 305 ECM.

[bkn259]

No i didnt do that. Is there anything else that needs to be done after swapping ecms?

[Polecat]

welcome...changing or getting the new one tuned, you shoudl see huge gains.

[bkn259]

Welcome To Fullsize Chevy Brian

Did you change the ECM when you swapped in the 350?It will not run right if you are using the stock 305 ECM.

do i need to get an ECM from a 95? or what differant years will work as long as its the 350 map?

[def1]

tbichips.com This guy can get your truck up and running with a nice chip. He is your best bet, second to making your own chips.

A stock ecm from a `94 pickup would also work fine. Just make sure it came from a 350 truck with the same options such as transmission, gears, etc. As far as I know, the `95 computer is a different animal.

Are you still running your original tbi and injectors? You need larger injectors and it wouldn't hurt to bump up the fuel pressure on the regulator.

[bkn259]

tbichips.com This guy can get your truck up and running with a nice chip. He is your best bet, second to making your own chips.

A stock ecm from a `94 pickup would also work fine. Just make sure it came from a 350 truck with the same options such as transmission, gears, etc. As far as I know, the `95 computer is a different animal.

Are you still running your original tbi and injectors? You need larger injectors and it wouldn't hurt to bump up the fuel pressure on the regulator.

everything that i am reading says that the fuel pressure is 9-13 psi for either the 305 and 350 so what would bumping up the pressure help? how what is the size differance between the 305 and 350 injectors?

[bkn259]

so i called the local salvage yard today and asked if they had an ecm for a 94 1500 that has a 350 and they said that there are 4 differant ecm's available. any clue which one it is and what the differance is? i just want to make sure i get the correct one so i can get this truck up and running. thank you.

[def1]

can't remember the flow rate of the injectors at the moment, but I know that the 305 injectors will make you run very lean. The stock 350 injectors with 13 psi on the regulator is barely enough to run a stock 5.7. These engines start to get happy around 14 psi. I helped my dad set up a tbi engine once in his datsun 280z since I had just finished up my truck, but only had 305 injectors on hand from a junkyard camaro. It loved to stall.

[bkn259]

i went to the salvage yard today and got an ecm out of a 95 with a 350. do i need to just swap the ecms or take out a chip from the inside and put that in. and will i need to have it reprogrammed or anything or will it fire the truck up and run right if i just plug it in or whatever. thanks for everybodys help