my problem is Iv just swapped in a TBI 350 (wires comp. everything) and it was going fine untill it got ready to start it and the injectors wont turn on. I tested them and they are working fine, and getting power, but the comp. wont "tell" them to spray. Is there a bypass or safety I missed? Do I need to loop something together or buy a pigtail or resistor? Do I have to ground the computer directly? I thought it had an internal ground that is part of the wiring harness. Any Ideas or suggetions will help. Thanks

 

Sounds like a module.

 

Not sure of your exact operation, but on some, the oil pressure switch kills fuel pressure if there is no oil pressure - did you reinstall / reconnect the oil pressure switch on the new motor?

Have you checked the ECM for any codes?

 

I second that module idea...

 

Check the ignition module. One sure way to tell is if the fuel pump primes but doesnt come on when the engine cranks. Thatll definatly be a possible sign that there is no reference pulse to the ecm. Also make sure that the positive side of the injectors is fed to a +12 volt source that remains uninterupted when the engine is running and cranked.

 

I checked the module with a volt meter and it is getting power, I dont know what els to look for, on it. How els can I check it? The Oil Pressure sender is also hooked up, I plugged all the original sensors in. I think it may be in the wiring because IM using the old harness. Unfortunately the "expert" I had helping me gut the diagnostic port out of it. Said I wouldnt need it (right) Would that affect this? The injectors fire as soon as you turn the key off but thats it.
I really dont want to because Im so close But I think I might have to break down and buy the Kit from Painless. Has any one used this kit? Thanks again guys

 

If it will crank all day lomg and only fire when you quit cranking then it sounds like the ignition module. I had the same thing happen to me. I replaced the module and it fixed it. There cheap enough to try and if you get one from Advance Auto or Auto Zone they will probably take it back if it doesn't fix your problem.

Steve

 

You took out the assembly line diag. link port!?!?! If so then your 'expert' deserves a good chewing out That is really one of your only ways to communicate with the ecm. W/O it your blind. If you havnt already done so try replacing the ign. module and make sure everything is in correctly. Also check to make sure the injectors have 12 volts at all times when the key is in the on and start position. Also, does the check engine light give its customary blink when the key is first turned to the on position? That will at least tell you the processing end of the ecm is ok. Still no garantee all is well inside the computer but its a good indicator that it should be ok.

Its unusual to have the injectors fire when the key is turned off. Did you or your helper change or take out any of the pins in the ecms 24 or 32 pin connectors? Might want to double check everything to make sure its all hooked up properly.

 

We didnt change any pins on the computer connections, and your right about him needing a good chewing. I will change the ignition module like everyone is suggesting, this manny people cant be wrong. I still have the port for the diagnostics. If I were to try and wire it back in would it still work the same? Also I will be unable to use the old intsterment cluster, so I will not have a check engine light (thanks again to my "expert" who had done this swap manny times before) Can I wire in my own light? Thanks, you guys are a great help. Its great to be able to get help from people who have been in the same situation.

 

I almost forgot. The Injectors spraying fuel when I shut the ket off, is a presure relief, to tkae the presure off the system. I just read that today. thanks again

 

The 'SES' light isnt super critical but it would help. You can jsut put a small bulb in its place, that would work fine. As for the port, thats essential, especially for situations like this where there is somehting that isnt working. Even though the ALDL only transmits at 160 bps, its still very useful, jsut the same. With winALDL, you could see if the computer is getting distributer reference pulses from the distributer when the motor is cranking. That would tell you right away if the ignition module or some related item is your problem. Id definatly recommend putting the aldl port back in.