Topic: Injectors 2 and 4 dead?

[war dept]

What tells the ECM to send the ground signal to the injectors? I have two dead holes, cyl 2 and 4. I got the wiring diagram and found a bad/corroded connection in the wiring harness from the ECU to the injectors, fixed that and it didn't help. Replaced the ECU and still nothing. There is a white wire and a white/red wire from The ECU to the injectors that sends the ground signal to the injectors. The ground signal is real weak. Any help would be great. Oh yeah 87 4 runner, 4cyl 5 speed non turbo.
Thanks
Bill

[gnob]

they batch fire, your wiring is still bad.

[war dept [OP]]

Batch fire, what's that? They all fire at the same time? The two wires from the ECM , white and white/red connect to all 4 white/red wires that go to the injectors. Any ideas on where I should look? Thanks for the help.

[Cheesemaker]

Sounds like your resistor is bad.  The signal that goes to/from? the injectors passes through the resistor that separates the signals into inj. 1 & 3, and inj. 2 & 4.  Sounds like the side that sends the signal to the injectors.  If you look on your passenger fender, it should be there, and covered with heat sink fins.  There should be two plugs that hook into the harness coming out of it.

There should be two plugs.  Unplug them both.  One should one terminal (+B), and the other with two (No. 10 & 20).  With a Ohm meter, measure the resistance between +B and the other terminals.  +B is the input to the Solenoid Resistor, and No. 10 & 20 is the output.  You should be able to get between 2 - 3 ohms each.  And this is if the output of the ECM is putting out.  And ohm meter is your best friend, and the FSM.  Which helped me out ALOT!!  


Bold type is quoted from FSM.  

[war dept [OP]]

I checked the resistor and have no resistance between the input and either of the outputs.

[MC387]

There are splices in the harness on the ground side of the injectors.  They have a tendancy to get corroded.  I found mine by stripping all the tape off the harness and following the wire down.  The splice was near where the wire for the AC compressor comes out.  I would unwrap the harness staring at the PCM untill you find the splice.  Just remember to seal it all back up with some quality electrical tape when you are done.  i did not have to remove the harness from the engine to complete this repair.