I just swapped back to TBI after a long time of running carb and now for some reason the injectors do not fire during crank. They fire once or twice as im letting off the key though and when its cold that is enough to start it sometimes. It runs fine once its started. Injector spray pattern is great.

This is what I know so far

the large pink wire is supposed to be hot in everything from run to crank. Seems like it powers the coil and the injectors.
I put a test light at the inj fuse block with a seperate ground than from the ecm and I am not getting power in run or crank, I only get a small flash of power as im turning the key toward crank and sometimes when i am letting off the key ill get another small flash

I would diagnose that as a faulty ignition switch but the car started fine with the carb. This means the ignition coil must have been getting power in crank



this schematic shows the rest of the circuit. Still though it doesnt explain why I am getting power only intermittently from the pink wire to the fuse block and why the car will run fine once its started if there is no power to the fuse block when i just turn the key to the run position.

Any ideas?

 

When you went from tbi to carb did you disable anything in your computer chip or maybe change out the computer chip.

The Trickster!!!!!!!!!!!!

 

do you have to wiggle your key to get vats to recongnize it ? cause I have same problem but I was told it could be vats..

 

i no longer have vats, i am running a 7747 truck ecm. The chip is the same chip that was running the tbi before I took it off. Even reburned another chip, i even tried another ecm with yet another chip. Same problem.

All signs point to ignition switch, i hope that is what it is