TBI no run

[noJeepshere]

My buddy's 86 S-10 Blazer with 2.8 V-6 won't run. I checked for spark (good) and fuel. The fuel pump runs and is putting out about 12 psi and the fuel is getting to the injector assembly and is even coming out the return line, but not very much.

Nothing is coming out of the injectors, however. I used the multi-meter to diagnose the plugs, there is little resistance to ground on that side, and the power side reads 120 milivolts when the key is turned on. I assume that is what it is supposed to be? everything we can find is plugged in and otherwise operating properly.

I'm stumped, the guy at the garage is stumped, and I was wondering what the brotherhood had to say? I was thinking the fuel pressure regulator in the injector assembly is not working, but I'm not sure.

 

[Russell]

Sounds like the fuse for the injectors is fried. You should meter out at battery voltage on one side of the injector wiring, and the other side should be open to ground. The ECM pulses the ground on and off to fire the injectors. I'd start there by checking the ECMA and ECMB fuses, you need to get 12V to the injectors with the ignition in the key on and start positions.

You can hook a 12V LED light, or just a regular ol' 168 marker light up to the injector's wiring and watch for flashing to confirm that the injector circuits are working properly. Autozone etc rents out "noid light" kits that do the same thing but are more visible.

 

[gotblazers]

isnt 12 psi pretty low for a FI motor

 

[Russell]

Nah, bang on for TBI! TPI and other multi-port injection systems run 40 PSI