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Injectors have no Pulse, not getting power to injectors?

Tiny
K CALDERONI
  • MEMBER
  • 2003 CHEVROLET AVALANCHE
  • 225,000 MILES
A mechanic put it on a scanner, and it got an injector code. I changed the injectors and put new ones in, but they are not getting any power to at least half of them. It idles, but when I disconnect the injectors, nothing happens on the right side. I disconnected two of them on the left side, and it almost shut off.
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Monday, June 12th, 2023 AT 3:15 PM

28 Replies

Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 109,885 POSTS
Hi,

If you have no power to the injectors on one side of the engine, have you checked the fuses? Each side or engine bank has a separate fuse for the fuel injectors.

Take a look below. Note there are injector 1 and injector 2 fuses. I need you to check both fuses and confirm there is power to and from the fuses.

Here is a link you may find helpful:

https://www.2carpros.com/articles/how-to-check-a-car-fuse

Also, pic 2 shows the under-hood fuse box. I highlighted the fuses to check.

Let me know what you find.

Take care,

joe

See pics below.
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Monday, June 12th, 2023 AT 10:35 PM
Tiny
K CALDERONI
  • MEMBER
  • 16 POSTS
Fuse number two was blown, I put a new fuse on it and restarted the truck, it still has no power to the injectors. I haven’t put a test light on it yet. But the fuse did not blow.
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Tuesday, June 13th, 2023 AT 5:12 AM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 109,885 POSTS
Hi,

Okay, if the fuse was bad, something is happening. When you check any of the injectors on the engine, do any of the pink wires have power to the bank in question? Also, check to make sure there is power to and from the fuse you replaced.

Let me know what you find.

Joe
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Tuesday, June 13th, 2023 AT 7:22 PM
Tiny
K CALDERONI
  • MEMBER
  • 16 POSTS
I put another fuse in, turned the power on, and it blew the fuse. When I pulled the fuse and checked the connections, the left side has no power. I’ve searched for the grounds that I could find and clean them and reinstall them. The only ground that I haven’t got to is the one on the driver side door rail under the dash. But I am really stressed out because it’s my only vehicle, and I work from paycheck to paycheck and it’s costing me a fortune. And I don’t know how to check the lines on the injectors. At least not with the test glad that I have which is included.
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Wednesday, June 14th, 2023 AT 3:05 PM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 109,885 POSTS
Hi,

If the fuse failed as you mentioned, disconnect each of the injectors and see if the fuse still fails. If it does, then we have a short between the fuse and injectors. If it doesn't fail, then connect one injector at a time to see which one causes it to fail.

Once that is determined, check the connector as well as the wiring to that injector. If it is good, we need to replace the injector.

Let me know. Also, the test light you have is perfect. It will do the job if we need to go that route.

Take care and let me know what you find.

Joe
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Wednesday, June 14th, 2023 AT 10:35 PM
Tiny
K CALDERONI
  • MEMBER
  • 16 POSTS
I pulled all the connections to the injectors, plugged a new fuse in, turned the key on, and checked the fuse. It’s still blowing without connecting any of the injectors. And it’s still the only fuse that blew.
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Thursday, June 15th, 2023 AT 10:44 AM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 109,885 POSTS
Hi,

If the fuse failed with the injectors disconnected, then we know it isn't a shorted injector. That means the short is in the wiring to the injectors. Are you able to trace the wiring from the injectors back to the fuse box? Also, are all connectors in good condition?

Let me know.

Joe
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Thursday, June 15th, 2023 AT 11:14 PM
Tiny
K CALDERONI
  • MEMBER
  • 16 POSTS
All the connectors seem to be in good shape. But I don't know how to test the connections without blowing the fuse again. I looked under the fuse box and the wires are all connected and in good shape. But I don't know how to find the wire from the fuse to the ignition. Because when I turn the key, it blows the fuse.
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Saturday, June 24th, 2023 AT 10:54 AM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 109,885 POSTS
Hi,

What to do is this. Disconnect the battery and check the power supply wire on each injector for continuity to ground. Pick a place on the engine or body that will provide a good ground for you. If there is a short in a wire to ground, it will have continuity. If there is no short, the circuit will remain open.

Here is a link you may find helpful:

https://www.2carpros.com/articles/how-to-check-wiring

Let me know what you find.

Joe
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Saturday, June 24th, 2023 AT 8:51 PM
Tiny
K CALDERONI
  • MEMBER
  • 16 POSTS
Oh, the friend of mine, and I checked the wiring harness for brakes, and there were none. We also pulled the plugs on the PCM unit and checked the wiring there, there were no brakes there either. It was still blowing fuses at that point. So, we put a 25-amp fuse in it to see if the injectors would fire and everything seemed to work okay at first. I drove it around the block, but the engine light came back on, and it started misfiring. I got it to a parts store and had it scanned. It gave me a P0 300 code. I got it back to the house checked all the injector plugs to make sure they were all plugged in all the way, and then I put a new 15-amp fuse in it and it didn’t blow when I turn the key on. I did this a couple of times to make sure. But the fuse still did not blow. I’m not sure what happened. I checked it with the test light, and both sides are lighting up whereas before only the right side of the fuse lit up. My friend thinks that the PCM might be bad. I’m going to test drive it around the block tomorrow because I have to work tonight and see how bad it still misfiring.
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Friday, June 30th, 2023 AT 4:15 PM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 109,885 POSTS
Hi,

Thanks for the update. And yes, that is a very good possibility. Be careful when you change fuses like that. It can cause more damage to something or even cause a fire.

If you have a chance, let me know what you find tomorrow. Also, clear the code and see if it comes back.

Take care,

Joe
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Friday, June 30th, 2023 AT 9:42 PM
Tiny
K CALDERONI
  • MEMBER
  • 16 POSTS
Can I clear the code by disconnecting my battery? I have seen this done before but I wanted to make sure that it was okay to do so.
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Friday, June 30th, 2023 AT 11:22 PM
Tiny
K CALDERONI
  • MEMBER
  • 16 POSTS
Can you also please send me a link to get a wiring diagram that I don’t have to pay for? I would really appreciate that if you can.
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Friday, June 30th, 2023 AT 11:24 PM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 109,885 POSTS
Hi,

As far as disconnecting the battery, it may work. Normally, it is based on the code type. As far as the wiring schematics are concerned, I don't have a "free site" to offer. I have access to most all of them so if you need a specific circuit, you can ask me, and I can get them for you for free.

Let me know.

Joe
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Saturday, July 1st, 2023 AT 6:48 PM
Tiny
K CALDERONI
  • MEMBER
  • 16 POSTS
Can you please send me a wiring diagram for the PCM to the right-side injectors? I think it’s #1 injector bank, #2 fuse. Then can you tell me how to test it with a multimeter? Thank you so much for your help with this.
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Sunday, July 2nd, 2023 AT 10:17 AM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 109,885 POSTS
Hi,

I would be happy to. If you look below, I attached the schematic and highlighted all the signal ground wires from the injectors to the PCM.

Note that each injector has a pink wire. That is the power supply. It should have 12v with the key in the run position or start position.

Here is a link that you may find helpful when testing wiring:

https://www.2carpros.com/articles/how-to-check-wiring

If you are testing for a signal ground, it is easier with a test lamp. Connect the test lamp alligator clip to the battery-positive terminal. Probe the ground wire with the test lamp. Have a helper crank the engine. If the ground is working, the test lamp will strobe on and off.

Let me know if that helps.

Take care,

joe

See pics below.
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Sunday, July 2nd, 2023 AT 10:44 PM
Tiny
K CALDERONI
  • MEMBER
  • 16 POSTS
I got a new PCM for the truck. But it won’t start until I can get it through the passkey system so I’m clearing the codes by disconnecting the battery cables and then connecting them with a jumper cable to get rid of the residual charge in the PCM battery. And then try doing the three, 10-minute cycles to reset the pass key code. But it drains my battery so quickly, and my battery charger is only a four-amp charger, that I can’t maintain a 12 V charge in the battery while doing that process do you have any suggestions other than taking it to a mechanic to have it done?
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Sunday, July 16th, 2023 AT 10:36 AM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 109,885 POSTS
Hi,

Your battery shouldn't drain that fast. Are you sure it is good? Also, could there be a heavy drain on the battery?

Let me know.

Joe
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Sunday, July 16th, 2023 AT 11:15 AM
Tiny
K CALDERONI
  • MEMBER
  • 16 POSTS
I got the engine to run well, but I got a p0641 code. So, I need to know what sensors are connected with the 1 circuit.
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Sunday, July 23rd, 2023 AT 10:24 PM
Tiny
K CALDERONI
  • MEMBER
  • 16 POSTS
And maybe you can tell me what to look for?
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Sunday, July 23rd, 2023 AT 10:25 PM

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