2G Cylinder 2 Misfire - Low Resistance on Plug?

[msisto]

Hey All,

I have a stock 98 GST with an AWD swap. I was driving to an appointment recently when I got a misfire in cylinder 2 (code P0302). This was accompanied by code P0202 (Injector Circuit/Open - Cylinder 2). My injectors are rebuilt ones, but I tried swapping out cylinder 2’s injector with a known-working one. No luck. Then, I tried swapping the plug from cylinder 2 with an adjacent one. The misfire followed cylinder 2’s plug, so I narrowed it down to either the harness or something it is connected to. I checked the resistance across the two receptacles in each receptacle that plugs into each injector. All of them gave me 400kohms of resistance except for injector 2’s receptacle, which read around 3Mohms - pretty low.

Is this indicative of a bad resistor pack? Could it be the ICM?

 

[Bleakley]

Edit. You have a ‘98.
I have diagrams for ‘95-‘96 only I believe.
It’s cake to diagnose the injector circuit.
I’ll Pm you my number if you want me to walk you through it.
Here are diagrams for ‘95/‘96. The pins may not be the same, but the circuits are going to be nearly identical...

Based on what you’ve said. You have proved out the circuit ALL the way to the resistor pack, and ruled out the injector.
Only things left now is:
Open In one of the resistors
Open in Wiring from resistor to injector
Open in Wiring from injector to PCM
Open in PCM itself. (Fried transistor)

Grab your multimeter, set it to test resistance, and ohm out the resistor pack, feed side wiring, and ground side wiring. Report back after that.

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[msisto]

Awesome. This is very helpful. I’ll do this today, especially since the weather is unseasonably warm where I am haha.

 

[msisto]

Okay. The ‘95-‘96 plug looks a bit different. Mine is missing one pin, I think. Regardless, on the feed side wiring, the three bottom pins were a consistent .766kohm across all three. The top two pins displayed 366kohms. On the three pins on the resistor pack, I got roughly 1.4Mohms (it was tough to reach them). On the two pins, I got 1.3Mohms. It’s looking like the resistor pack, would you agree?

 

[dustyboner]

this is the diagram for a 98. if you need other pages besides this one, just let me know.

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[Bleakley]

Okay. The ‘95-‘96 plug looks a bit different. Mine is missing one pin, I think. Regardless, on the feed side wiring, the three bottom pins were a consistent .766kohm across all three. The top two pins displayed 366kohms. On the three pins on the resistor pack, I got roughly 1.4Mohms (it was tough to reach them). On the two pins, I got 1.3Mohms. It’s looking like the resistor pack, would you agree?

You did not do this right. I promise you, if you do this exactly as I say, we’ll find your problem.

Disconnect battery, wait 5 minutes or so....

Take multimeter, set to test resistance. Test resistor pack for open or abnormally high resistance. —> disconnect the connector from the resistor pack and we’ll be probing the pack, NOT THE HARNESS. —> Red probe on pin 3 for duration of testing, black probe will probe all the other pins one at a time. Record your reading for each one. FSM says @ 68*F you should have 5.5-6.5 ohms of resistance.
Again, record each of your readings.

Take multimeter, set to test resistance.
Test wiring from resistor pack to injector #2 —> disconnect injector #2. disconnect connector on resistor pack.
Red probe on pin 4 of resistor pack connector a-80, black probe on pin 1 of injector connector a-56. Record your reading.

Take multimeter, set to test resistance.
Test wiring from injector #2 to pcm. You’re probably going to need a jumper wire to extend your leads. Lol. —> disconnect injector #2. Disconnect ecu. Red probe on pin 2 of injector connector, black probe on pin 14 of ecu connector B-53. Record your reading.


Report back. One of these is going to show up with much higher resistance (or out of limits) than all others.

 

[msisto]

Ah, ok. Thank you for the clarification!

 

[msisto]

@dustyboner Thanks for the diagram!