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2007 Chevy Avalanche 5.3 vin 3.

I bought a remanufactured engine. After installing it, the truck runs, but only bank 1 (1,3,5,7) is firing.

It has power to the coil packs on bank 2 (2,4,6,8), but no spark. I put in a new cam sensor, crank sensor, and all 4 O2 sensors, but bank 2 will still not fire.

  • What could be causing this?
  • How do I diagnose it?
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  • You have electric power on the 12v side of the bank 2 coil pack but no spark, is that correct? Jan 8, 2016 at 0:03
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    Nothing that you have replaced would fix the problem you are having. The cam sensor or crank sensor would affect both sides at the same time. The oxygen sensors have nothing to do with the ignition. Because only one side is affected and after an engine replacement I would look at the wiring. Something in the wiring that only affects the one side. A connector that is not properly seated or a ground that you forgot to connect.
    – vini_i
    Jan 8, 2016 at 0:23
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    The GM coil near plug system incorporates the "igniter" into the coil. To fire, the coil requires a power, a ground and signal. One of the three is missing. If there is power, i suspect that the ground that affects all the coils is missing. It is possible that some pass through connector that has all 4 signals in it is unplugged but is less likely. Also double check all the fuses. GM PCMs have multiple power and grounds. If one is missing they can do strange things. @DucatiKiller a few notes.
    – vini_i
    Jan 8, 2016 at 1:27
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    @Shaine - You can pull the plug on the side of the block, just above the starter. If you can look in there (maybe take a pic with a smartphone?), you can see the reluctor wheel. Here is a pic ... in the picture the one on the left is the 58x (two wheels in one) and the one on the right is the 24x. Really, even if I did suggest this, I don't believe any cylinders would fire if this were the issue. I'm still thinking vini_i is correct on the ground issue. Try running a separate ground just to make sure. Jan 9, 2016 at 1:34
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    Was this ever resolved? Apr 24, 2017 at 20:19

3 Answers 3

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This post is old but today I was called out to a truck with the same problem. It turned out that one of the coils had shorted out and blew the fuse for the left bank. I replaced the coil and replaced the fuse and all the cylinders were firing again. The fuse was a 15 amp under the hood and labeled *2 with a note to check the manual as to it's purpose. Next to it was another labeled *1 and I would guess that to be the other bank. Hope this helps.

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  • Dan, you posted a reply to check the 15 amp fuses for one bank. I had that problem and searched the internet for quite awhile till I came upon your post. I checked the fuse and it was blown. Back on the road. Found two frayed wires that had shorted to ground. Thanks. Mike
    – Mike Duke
    Dec 1, 2019 at 1:38
  • Thanks Dan..was having the same problem, and traced every wire I could find..buying parts, map sensor, new plugs and wires, couple other sensors, so I was in $300 and still pulling my hair out..then read this post and waalaa, a blown fuse..#2..hard to believe a 15 amp fuse powers that whole bank..glad I didn't start buying coil packs..lol..thanks again for the post!!..
    – Charlie
    Aug 29, 2020 at 19:50
  • On my Suburban it was a 20 amp inj A and inj B.......Thanks for the post Jun 23, 2021 at 2:25
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Check the battery, maybe some cables which should be connected to the sparkplugs aren't. Check the alternator, maybe it is not restoring enough power for both banks. A friend of mine had the same problem. He checked the sparkplugs and one bank had no power, because of loose cables. But please do not try to drive! Your issue could badly affect the crankshaft and the conrods of the second bank.

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The last one I did the #2 side was firing when first started then after about 30 to 45 seconds the whole side would miss . I found corrosion in the under hood fuse block around the #1 and #2 fuse connection sprayed Kroil penetrating lube in those fuse ports and it is corrected the problem?

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