Hi all, I am new to the board and have an interesting problem I hope you all can help with. I am building a 69 Bird with an 86 TPI (305) bolted to a freshly rebuilt 89 350 roller. This system ran fine in the 69 on the 305 but now that I have it on the 350 it cranks but will not start unless I squirt a little fuel into the plenum, then it starts and runs fine with good throttle response. (Note: I have not been able to drive or test it under load as I have no drive shaft yet). Fuel pump (280Z) seems ok I hear it run for a few seconds when I turn on the key, I have even hard wired it to run constantly with no change, fuel pressure at the Schrader valve is 45 PSI key on, 40-42 running, minimal bleed down after shut down, appears to have a minor seepage at one line fitting. It has the cold start (ninth) injector, ecm number is 1227165. The entire TPI system came from a running 86 IROC 305, I have tried 350 injectors and the ones from the 305 with same issue. Computer seems ok, code 12 and an O2 sensor code 44 after it warms up. Checked injector wiring with noid light, no pulse when cranking, good pulse once running. What would cause the no injector pulse while cranking? Could the ignition module or a short in the Dizzy cause this.
Any ideas? Thanks

 

When you turn the key to ON (not start) do you hear the pump run for a few seconds and then shut off?

 

Yes: I hear it run for a few seconds when I turn on the key, I have even hard wired it to run constantly with no change, fuel pressure at the Schrader valve is 45 PSI key on.

 

Morning All. I went through all the trouble shooting guides in the Chevy TPI swappers guide (again) and it points to the ECM.... But It runs ok once primed, how could the ECM be bad, can this be correct? Any other ideas?

 

Well I tried another ignition module, no change. Tried swapping the fuel pump relay, and then the ESC, no change. Put everything back together and it will not run at all, so it must be the ECM. I do not have a spare one, so unless there is disagreement from you all, I will try a trip to the bone yard. Thanks.

 

Last couple times I heard of this, it was the prom. You already have cold start. I'm assuming it's functional. Do you have the right prom for it?

If you have your cold start disconnected, or blocked off, or it doesnt work, but are running the 85-88 cold start program, your engine will do that.

1989 proms were programmed to provide cold start fuel from the main injectors, unlike the earlier motors, which use cold start.

Let me guess, the engine runs great and starts fine after it gets hot but doesnt cold start worth a damn?

 

Found the problems, my wiring harness shorted so my cold start injector circuit was not complete and the power to the ECU was lost while cranking. Don't quite understand why it would start at all. Glad I did not by that new computer. Thank you all.

 

This is my first post. I have similar situation with my 91 Z28. If I spray starting fluid, it cranks right up, then dies after spray is burnt off. I checked fuel Presure at the rail. It is at 45 with no leak down. Ignition system checked with MSD ignition spark check instructions. Injector wiring harness checked with noid light. It flashes when cranking. It boils down to the injectors, but can all injectors go out at the same time? There is no sign of combustion without the starting fluid. Could it be timing? Please help.

 

Your injectors may be stuck. the same thing happened to me yeasterday when i first started my 350 tpi that i swapped into my 89 rs. What i did was hooked a volt meter to the injector and then to a battery. it broke them free and then started and ran fine. Or you can replace or clean the injectors.

 

Thanks for the reply. The funny thing is that I had just added some stabil about a week before this problem occurred. I will try it this weekend and let you know how it goes. Also, I was shopping around for injectors already. I am thinking of the 24lbs, but it may be overkill for the stock 305 TPI though.

 

Great Advice. All eight injectors were stuck. I could not figure out how to connect the voltmeter to the injector, so I used direct current with a 16 guage wire and a 5 amp inline fuse to break them loose. It ran rough, but it ran. The service engine light was actually blinking and diming, so I changed out the computer and it runs alot better than before. Thanks for the advice.