Intermittent power, rough running problem.
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Intermittent power, rough running problem.
I posted this reply to another thread and also wanted to get it out here in a new one. It had been a frustrating problem that had us looking in several different areas and until this last time, where we were lucky enough to have it occur close to the dealership, had been leaving no good clues as to what was up.
tWith my truck throwing no codes when loosing power and sounding/running rough we got lucky had this problem occur close to the dealers. In the past if I had shut the truck off and restarted the problem disappeared and with no codes to check we were kind of in the dark looking for the problem.
Here is what we found when we were able to catch the truck doing this and get a laptop hooked up to it. One bank of injectors was out. When the ECM detects a shorted injector it will take out all four on that bank, even for just a momentary short, and leave them out until you restart the truck.
I had had this problem occur at various times, sometimes associated with a bump sometimes not. Doesn't record or leave a code after you have restarted, have to catch it in the act. So with the truck acting up and laptop connected, showing four injectors not working, one of the suggested problems was a faulty or shorted injector. There are three wiring harness's coming from (ECM?) the controller on the passenger side firewall. The harness in the middle, the larger one, had been contacting the engine about one foot from the controller and had a small rub on the outside. When flexing the harness and contacting the block we were able to duplicate the problem. They repaired the harness, got a little slack into it by manipulating it, and also added a piece of plastic conduit over the harness in that area to prevent it from reoccurring should it rub there again.
Happy camper once again. Hope this helps someone else out. It has been a hard problem to get ran down. 
tWith my truck throwing no codes when loosing power and sounding/running rough we got lucky had this problem occur close to the dealers. In the past if I had shut the truck off and restarted the problem disappeared and with no codes to check we were kind of in the dark looking for the problem.
Here is what we found when we were able to catch the truck doing this and get a laptop hooked up to it. One bank of injectors was out. When the ECM detects a shorted injector it will take out all four on that bank, even for just a momentary short, and leave them out until you restart the truck.
I had had this problem occur at various times, sometimes associated with a bump sometimes not. Doesn't record or leave a code after you have restarted, have to catch it in the act. So with the truck acting up and laptop connected, showing four injectors not working, one of the suggested problems was a faulty or shorted injector. There are three wiring harness's coming from (ECM?) the controller on the passenger side firewall. The harness in the middle, the larger one, had been contacting the engine about one foot from the controller and had a small rub on the outside. When flexing the harness and contacting the block we were able to duplicate the problem. They repaired the harness, got a little slack into it by manipulating it, and also added a piece of plastic conduit over the harness in that area to prevent it from reoccurring should it rub there again.
Happy camper once again. Hope this helps someone else out. It has been a hard problem to get ran down.
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Joined: Sep 2010
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I posted this reply to another thread and also wanted to get it out here in a new one. It had been a frustrating problem that had us looking in several different areas and until this last time, where we were lucky enough to have it occur close to the dealership, had been leaving no good clues as to what was up.
tWith my truck throwing no codes when loosing power and sounding/running rough we got lucky had this problem occur close to the dealers. In the past if I had shut the truck off and restarted the problem disappeared and with no codes to check we were kind of in the dark looking for the problem.
Here is what we found when we were able to catch the truck doing this and get a laptop hooked up to it. One bank of injectors was out. When the ECM detects a shorted injector it will take out all four on that bank, even for just a momentary short, and leave them out until you restart the truck.
I had had this problem occur at various times, sometimes associated with a bump sometimes not. Doesn't record or leave a code after you have restarted, have to catch it in the act. So with the truck acting up and laptop connected, showing four injectors not working, one of the suggested problems was a faulty or shorted injector. There are three wiring harness's coming from (ECM?) the controller on the passenger side firewall. The harness in the middle, the larger one, had been contacting the engine about one foot from the controller and had a small rub on the outside. When flexing the harness and contacting the block we were able to duplicate the problem. They repaired the harness, got a little slack into it by manipulating it, and also added a piece of plastic conduit over the harness in that area to prevent it from reoccurring should it rub there again.
Happy camper once again. Hope this helps someone else out. It has been a hard problem to get ran down.
tWith my truck throwing no codes when loosing power and sounding/running rough we got lucky had this problem occur close to the dealers. In the past if I had shut the truck off and restarted the problem disappeared and with no codes to check we were kind of in the dark looking for the problem.
Here is what we found when we were able to catch the truck doing this and get a laptop hooked up to it. One bank of injectors was out. When the ECM detects a shorted injector it will take out all four on that bank, even for just a momentary short, and leave them out until you restart the truck.
I had had this problem occur at various times, sometimes associated with a bump sometimes not. Doesn't record or leave a code after you have restarted, have to catch it in the act. So with the truck acting up and laptop connected, showing four injectors not working, one of the suggested problems was a faulty or shorted injector. There are three wiring harness's coming from (ECM?) the controller on the passenger side firewall. The harness in the middle, the larger one, had been contacting the engine about one foot from the controller and had a small rub on the outside. When flexing the harness and contacting the block we were able to duplicate the problem. They repaired the harness, got a little slack into it by manipulating it, and also added a piece of plastic conduit over the harness in that area to prevent it from reoccurring should it rub there again.
Happy camper once again. Hope this helps someone else out. It has been a hard problem to get ran down. 
Lead Driver
Joined: Jan 2010
Posts: 6,600
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Thanks for the information!
Yes, one would think the ECM would report an issue.
Does anyone know if this type of issue could cause long term effects with the remaining bank of injectors or stress on other parts of the engine?
Forgive the potentially silly question; I work with computers for a living.
Yes, one would think the ECM would report an issue.
Does anyone know if this type of issue could cause long term effects with the remaining bank of injectors or stress on other parts of the engine?
Forgive the potentially silly question; I work with computers for a living.
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