I'm finishing up my 350 TPI swap. Here's the specs on the motor. New short block, l31 poted vortec heads, lt4 hot cam, roller rockers, sdpc tpi baseplate, slp runners (with 9th injector hole plugged), 24# used LT1 injectors, mildly ported plenum, hooker headers, All new ignition components except the distributor, cap, rotor, msd coil, msd plug wires, bosh platinum plugs, msd 6al ignition box.

I'm getting a nice spark and i checked timing and it should be right on yet the engine keeps cranking over. I used a noid light and there are injector pulses but the light is very dim, basically just the filiment lights up. I checked all the ground connections and even used an ohm meter and each ground wire on the connectors for the computer has about 1 ohm of resistance to the nut for the seat. So all the grounds are good. So i figured it was a computer problem so i bought a new computer and still it does the exact same thing. The prom in it is for an 86 305 TPI auto, but it should be able to start using that. I have to send the memcal away and get the new custom bin burned on it.

Tomorrow i plan on lifting the fuel rail and seeing if the injectors are firing fuel. The engine should be flooded but i hardly even smell any fuel on the plugs.

Also fuel pressure drasticallly drops off when i stop cranking. When I turn the key to run it gets to about 15 psi and when i crank it over it jumps to 40 or so but when i stop cranking, in about 20 seconds almost all the pressure is gone.

Any ideas as to what could be causing my problem? My goal is to get it running by wednesday, my 18th birthday.

 

is the prom for the 86 tpi not for the cold start injector? you need to program the prom to get the car to start with the cold start injector pluged if the original car had one.

 

The 86 still has the cold start programed into it. I'm sending that away tomorrow to get a new bin burnt onto it though. Hopefully that'll change it.

 

Does fuel pressure drop rapidly after the pump is primed? 15psi is not adequate. It should be something like 45psi when primed.

I'd be wary that those injectors are leaking a lot or grounded. Maybe try your stock injectors.

 

my fuel pressure does the same thing. i had the same exact kind of problem when i went to stealth ram. my coil decided to play tricks on me, it wouldnt start the car with the plugs in the chamber, i guess compression kept them from firing. i put a new coil on and it fired up first try. the injector pulses dont make the test light very bright on my car either.

 

The coil is a brand new msd coil. I bought a new fuel pump yesterday, i'm gonna start putting it in tomorrow. Hopefully that'll be it.