Two injectors wide open with key on
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"With a VOM, KOEO, all of the injector plugs read 12 volts".
ONE wire in each inj plug is HOT. ONE wire is not.
If you are checking the TWO inj harness pins with both VOM probes and you have 12V, then there's an issue.
NOTE that there are different color wires for the ground side and a common color for the 12V supply side, in EVERY inj harness plug.
Put 1 VOM probe, the RED one, on the common color wire and the other probe, the BLACK one, on a good ground.
NOT on the other harness wire. Get 12V? You should.
If you are checking across the 2 pins in the harness and are getting 12V, That means the inj harness negative side is either shorted to the engine or the PCM driver is shorted.
ONE wire in each inj plug is HOT. ONE wire is not.
If you are checking the TWO inj harness pins with both VOM probes and you have 12V, then there's an issue.
NOTE that there are different color wires for the ground side and a common color for the 12V supply side, in EVERY inj harness plug.
Put 1 VOM probe, the RED one, on the common color wire and the other probe, the BLACK one, on a good ground.
NOT on the other harness wire. Get 12V? You should.
If you are checking across the 2 pins in the harness and are getting 12V, That means the inj harness negative side is either shorted to the engine or the PCM driver is shorted.
I checked the wiring harness pins with red probe to power pin and black probe to ground and got 12 volts. I also checked across the two pins in the inj plug and got 12 volts. I did this on all 8 of the plugs. Is there any way to check the computer driver? If I check from the ground pin on the inj plug to the engine block, should I get a 0 ohm reading or a max reading?
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If you know for sure they sell Chinese knock offs, please send me a pic of what a genuine Bosh 210 looks like. Badmouthing some company doesn't help me solve any problems.
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The Bosch injectors I bought had boxes with a number you can type into a Bosch website to check their authenticity.
on each injector plug one side will be hot with koeo and the other side should be infinite ohms to ground.
With koeo if you can see 12v across the two pins in the injector then something on the ground side is shorted. I’d start with unplugging the ecu and see if it’s still 12v. If so, you have a smashed wire. If not, it’s something in the ecu.
on each injector plug one side will be hot with koeo and the other side should be infinite ohms to ground.
With koeo if you can see 12v across the two pins in the injector then something on the ground side is shorted. I’d start with unplugging the ecu and see if it’s still 12v. If so, you have a smashed wire. If not, it’s something in the ecu.
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Verdad Gallardo Thread Starter
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I received the new ECM (E38) and I still have the same problem. And to back up a little, the title should be "all 8 injectors are on at key on".
I checked with the ecm unplugged---inj plug ground wire to ground and got no continuity. I don't know where the ground is coming from with key on.
Any more ideas??? Thanks
I checked with the ecm unplugged---inj plug ground wire to ground and got no continuity. I don't know where the ground is coming from with key on.
Any more ideas??? Thanks
Get a pin out of the PCM, open the harness up and start checking the wiring.
I'm not sure why you didn't start with this in the first place.
The swap harness wasn't wired correctly.
I'm not sure why you didn't start with this in the first place.
The swap harness wasn't wired correctly.
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From: Bostwick, GA.
This..... Sounds as tho the initial prime shot is continuous.
OP... Did you load the same program that was in the original pcm into the new one?
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Old Buzzard: I have an external fuel pump so I don't use the fuel pump relay supplied with the harness---but the relay is still there. I will pull it and see if it releases the grounds. The (new) E38 was vin matched---as far as I know, it is a stock 2012 GMC with a corresponding OS. I did change a lot of the parameters to match my setup. Another strange thing---from the black computer plug, from the the big ground pin to engine ground, I get continuity. Also from the black ground to any of the power pins on the injectors, I get continuity. And, from the same ground pin to any of the red and pink wires in the fuse block, I get continuity.
I will go pull the relay and see whats up and post results.
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OK, I pulled the F/P relay and no change.
The continuity readings above were with both computer plugs disconnected. And no power.
My problem is that I don't know where to start looking even if I take the cover off the harness. There should be a good starting point ??
I am going to remove the harness in a few minutes and see if I can tell what's going on.
I have a stock 2012/6L80 harness and checked from the black plug ground to the injector power pins, and NO continuity. It is not connected to anything.
Thanks for any suggestions.
The continuity readings above were with both computer plugs disconnected. And no power.
My problem is that I don't know where to start looking even if I take the cover off the harness. There should be a good starting point ??
I am going to remove the harness in a few minutes and see if I can tell what's going on.
I have a stock 2012/6L80 harness and checked from the black plug ground to the injector power pins, and NO continuity. It is not connected to anything.
Thanks for any suggestions.
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I unplugged all of the sensors getting ready to pull out the harness. Only left the ground wire connected to the block. I checked the #73 pin on the black ECM plug to the positive side (pink) of the injector plug and had continuity. Last thing---I removed the plug from the T42 trans controller---no more continuity. WTH
I have an extra T42 and will go check that one plugged in.
The other T42 does the same thing as the one on the harness.---Continuity from ground pin to positive side of injector.
I have an extra T42 and will go check that one plugged in.
The other T42 does the same thing as the one on the harness.---Continuity from ground pin to positive side of injector.
Last edited by dw456post; Nov 25, 2023 at 10:16 AM.
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Sounds like something wrong in the harness. They either tied a pink wire in with the rest of the grounds or a section got smashed or something like that.
maybe a bad crimp and there’s some strands poking out from a terminal and touching one next to it?
maybe a bad crimp and there’s some strands poking out from a terminal and touching one next to it?
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Trend Setter: I guess I will find out. Next step, expose all of the wires. What gets me is that when I unplug the T42, the ground goes away.
Old Buzzard: It's not a reworked harness---its a China harness. I didn't know at the time when I traded for it. There is no wiring diagram or support. It's almost a waste of time to check this thing. I should probably order a good one and be done with it. This has set me back a long time. At least my cylinders are clean and I have had 3 oil changes without even firing the engine. (gas in oil).
Old Buzzard: It's not a reworked harness---its a China harness. I didn't know at the time when I traded for it. There is no wiring diagram or support. It's almost a waste of time to check this thing. I should probably order a good one and be done with it. This has set me back a long time. At least my cylinders are clean and I have had 3 oil changes without even firing the engine. (gas in oil).
Trend Setter: I guess I will find out. Next step, expose all of the wires. What gets me is that when I unplug the T42, the ground goes away.
Old Buzzard: It's not a reworked harness---its a China harness. I didn't know at the time when I traded for it. There is no wiring diagram or support. It's almost a waste of time to check this thing. I should probably order a good one and be done with it. This has set me back a long time. At least my cylinders are clean and I have had 3 oil changes without even firing the engine. (gas in oil).
Old Buzzard: It's not a reworked harness---its a China harness. I didn't know at the time when I traded for it. There is no wiring diagram or support. It's almost a waste of time to check this thing. I should probably order a good one and be done with it. This has set me back a long time. At least my cylinders are clean and I have had 3 oil changes without even firing the engine. (gas in oil).
Determine what pins are for the 7&8 injector control wires from the ECM and follow them.
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I ordered another E38 and the same problem.
I pulled a good E38 off one of my vehicles and same problem.
I removed the China harness and used a stock 2012 truck harness and it fired up.
I sent the POS harness back. It is out of warranty so they are going to replace it instead of refunding my money. Maybe the new one will be wired correctly.
I can't use the stock harness because no accelerator plug, no OBDII plug, and I would have to use the huge truck underhood fuse box. And its 6L80 and I have a 4L80.
Thanks for all the support.
Another note: Somebody said when key on, and I could read 12v across the injector plug, I had a problem. I checked two other vehicles and at key on, you CAN read 12v across the injector plugs.
I pulled a good E38 off one of my vehicles and same problem.
I removed the China harness and used a stock 2012 truck harness and it fired up.
I sent the POS harness back. It is out of warranty so they are going to replace it instead of refunding my money. Maybe the new one will be wired correctly.
I can't use the stock harness because no accelerator plug, no OBDII plug, and I would have to use the huge truck underhood fuse box. And its 6L80 and I have a 4L80.
Thanks for all the support.
Another note: Somebody said when key on, and I could read 12v across the injector plug, I had a problem. I checked two other vehicles and at key on, you CAN read 12v across the injector plugs.
It's the ground that is given and taken away for the control of each injector by the PCM I believe. If the injector plug was powered/grounded all the time obviously the injector would be open all the time so not sure what you were seeing there.
Thanks for updating the thread. It's frustrating when someone just disappears after they fixed their problem..
Last edited by mk3cn4; Dec 8, 2023 at 07:41 AM.
