i have put a 85 tpi on my 75 monte which has a rebuilt 350. altho it is run by a 727 vette computer speed density. i have a msd external pump and new venom 19 lb injectors. i know that normally the 350 has 22 lb injectors but when i had the prom burned i told them to use 19 for injector reference. i have looked into the pressure regulator and there is no gas leaks there. but if i unplug the #2 & #4 injectors it smoothes out and increases in rpm. the tps and iac are set correctly as well as the inital timing. i can here the computer working on the timing and it will backfire every once and a while on the pass side. all of the sensors are new. the return to the tank is only 1/4" because my 5/16 is currently plugged at the tank. it acts as tho it is flooding and when i kill those 2 cylinders it comes alive. it did this before i put the new injectors in. there is a flex hose that i can pinch to the fuel rail would this tell me anything. i also purchased a chilton for 82-92 camaros but to no help. any help would be greatly appreciated. thanks.

I'm sure you have an O2 sensor plugged in to help the ECM make its decision.

Have you measured the fuel pressure at the rail? Should be min 45 to 50 PSI., I think.

All pass side injectors have the same wire color code, as does the driver side injectors.

If you have a Speed Density program, I'd unplug the MAF sensor to see what it would do.

I assume the engine mechanicals are good, no leaking valves, etc.

You might try returning the fuel into a gas can with a 5/16 hose to see if available fuel is reduced at injection time. If the return line is smaller than OE design, then it is going to show as a restriction to flow and create more pressure in the fuel rail and could possibly richen the mixture injected.

You've made sure the start injector is not leaking and turned off after ~8 seconds from cold startup?

O2 is plugged in but im still running thru open headers at the time.
having a friend come over with a scanner pressure guage and digital multi tester
running speed density no maf
motor has a fresh rebuild first run with this tpi
no cold start uses all 8 injectors for starting
will also try the gas can idea to see how much is returning to the tank. thanks

did i read that right, that u had them burn you a prom for 19lb injectors?the 350 definatly needs 22lb-ers.as far as the fuel pressure it should be between 39-44 psi for a stack 350.and everette is right you defibatly need a 5/16" return line.when u had the prom burned what pressure did you tell them you were gonna run?you have to sync the pressure from the regulator to the prom.plus u need that o2 sensor hooked up otherwise the computer will read lean and dump more fuel.what do the plugs look like?also try this site out they know a buch about tpi stuff

http://www.thirdgen.org/techbb2/index.php?s=

mike

...also try this site out they know a buch about tpi stuff

http://www.thirdgen.org/techbb2/index.php?s=

mike

Second the recommendation on thirdgen. I also recommend you download their ECM edit software, get some diagnostic software, install it on a laptop and learn just exactly what the engine is doing. You'll be able to edit, and burn your own proms for about $200 invested. I also recommend the wideband O2 setup. Oh and can't forget a pressure guage and adjustable pressure regulator.

TPI is great in that it is very hackable. But making that big of a shift will require some Prom editing. A friend of mine went through this with the equipment I mentioned above. It took him about 90 EEPROM burns to get it set up just right.