What could cause the whole bank of fuel injectors to have no power ?

Anyone with similar problems ?
Thanks

 

The whole bank as in 1 side, or all of them ?

if you are talking all of them, the fuse off the PCM power relay, BJB fuse # 18 is a place to start ( this also powers the coil to the fuel pump relay ).

Are you sure there is not + VDC at the injector ?
This is the red wire checked to an external ground ( the injector is grounded by the PCM to make the pulse width ), when the key is in the start or run position ( this is the only time the PCM relay has the Normally open contacts closed ).

 

A 2000 doesn't use bank-fired injectors, so if all the injectors on one side of the engine are dead, the wiring harness is damaged, probably behind the intake where it wraps from the driver's side to the passenger's. How exactly are you checking for power?

 

NOID test.... the whole bank dont light up. All 4 cylinders

 

Check voltage from the Red wire to battery (-) with the key in RUN. If it shows 12V, check continuity (resistance, diode) from each OTHER injector wire to the engine connector, with the key OFF, the suspect injectors unplugged, and the engine's inline connector disconnected.

 

Nope, wiring harness is intact. Took the whole intake header and checked the wirings.
No cuts, melt or anything.

Its a really weird problem.

I called and asked around for advices, some mechanics told me to check the relay switches and trace all my wires...

The switches part im okay with it but tracing the wires is pointless.... well I checked one set and they were okay... but not going to do all. No need to.
IF one dont show up, the other also wont.


SO now im back to blaming the ECU.

 

You can't blame the PCM until you've eliminated everything else, including the wiring. Check voltage & resistance. You don't have to put the intake back on - just plug the harness back in.

Even if you remove the PCM, open it up, & find it burned, you won't know if it burned on its own, or if it was because of a wiring fault.




...until you plug the replacement in & it smokes, too.

 

But its very unlikely to lost power to a whole side of the engine. Meanwhile the spark plugs still spitting fires. These two go on the same wiring harness, so ruled that out by logic tells me its not the wires. Its either the switches or the ECU

 

That's not logic - it's a guess, based on an illogical assumption. The harness doesn't have to be sheared clean through ALL the wires; it's VERY possible for some wires to be pinched/cut/worn/chewed through, and others to be perfectly fine.

But it's your truck...

 

Your logic and troubleshooting methods are both faulty.

Just because you have spark you cannot assume that you also have power to the injectors unless you also have checked the schematic to see how the circuit is laid out. Additionally, a "noid" light cannot test for power - it can only test for BOTH power and the necessary ground pulse.

Get the voltmeter out and perform the voltage checks already indicated. Get the schematics out while you're at it and quit guessing and assuming.

 

My guessing was right on the money. I just got done checking. All the connectors are working.
So IT IS the ECU/PCM.

I also noticed it said "REMANUFACTURED" on the ECU. So it might have gone bad in the past, and replaced. Now its going bad again ? ... hmmm ECU rarely go bad unless something triggered it.

Getting it reflash tomorrow with a used one on Ebay