Tbi swap build thread

[brontotx]

With ignition on, you should have 12V+ on both the red and white wires. The injectors do need a solid 12V, so if your battery is weak, they may not fire. The blue and green wires are triggered by the ECM to ground for firing each injector. There are ways to check the injector pulses at the wiring connectors, but require specialized equipment like an oscilloscope or trigger lights.

It is possible the injectors are stuck from having gummed up sitting around -this is what the problem was with mine when I first tried to start it and I was able to get one un-stuck by rapping the injector pod on the side with the handle of a large screwdriver. If you can get one to spray (the truck will run rough on just one injector), a good way to see if they are operational is to use a strobe from a timing gun. I ended up having to buy a new injector for one side.

I doubt that excessive fuel pressure is the problem - I'm pretty sure the bypass regulator is after the point where fuel is pressurized to the injectors. While I'm not sure what harm could be done since I've never tried this, you could try to momentarily connect a ground to the terminal of the injector that doesn't have 12V+ to see if it sprays (to try this, you have to have fuel pressure at the injector). If it sprays, there is either an ECM or wiring problem between teh ECM and the injector, otherwise it is probably the stuck injector I mentioned above.

BTW, I'm no expert on this, I've just been down this road before and I'm trying to give you the benefit of what little I know. Hope this helps and good luck.

Mark