3 CYLINDER MISFIRE ON 2003 PONTIAC VIBE

  • Tiny
  • ChrisKS
  • 2003 PONTIAC VIBE
  • 4 CYL
  • 2WD
  • AUTOMATIC

Trying to work on my friend's 2003 Pontiac Vibe after she had a complete engine failure. We replaced the engine with a salvage & had it running fine when it was up on jacks. After it was let down, however, it ran for a few seconds, died & refused to even turn over. We found & replaced a blown AM2 fuse & found the wires to the Cylinder 3 fuel injector were pinched & shorting out on the engine block. Clipped & rejoined the affected wires but now, we have a check engine light & it is giving a code for #3 cylinder misfire.

We checked power to the spark plug & coil pack - all fine, the fuel injector plug has voltage but the #3 injector is still not squirting fuel. With the fuel rail out, we swapped the injector plugs over & the problem follows the #3 plug.

Could the #3 cylinder injector wire getting pinched & shorting out on the engine block have turned something off in the computer, maybe as a safety? And if it has, how do we turn that cylinder back on?

Thanks & I hope someone out there can understand at least some of my ramblings. LOL

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Saturday, April 9th, 2011 AT 1:42 AM

3 Replies

  • Tiny
  • PROTECH1980
  • EXPERT
  • 928 POSTS

Can you tell me the 8th digit of your vin number, I will get you a diagram of the injector circuit to see if you have pulse coming out of the pcm for that injector, the wire may be broken some where between the pcm and the injector.

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Saturday, April 9th, 2011 AT 1:53 AM
  • Tiny
  • ChrisKS
  • MEMBER

Hi - thanks for the fast response! The 8th digit is 8.

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Saturday, April 9th, 2011 AT 2:19 AM
  • Tiny
  • PROTECH1980
  • EXPERT
  • 928 POSTS

Here is the wiring diagram, it looks like pin 3 white wire coming out of the pcm is for injector 3, find this and back probe it to see if it is pulsing ground, just to make sure you said you have power on one side of injector connector but no pulse on other side? And the rest of injectors are working normal? If that is the case and you have pulse out of pcm but not at injector, find and repair open wire between the two.

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Saturday, April 9th, 2011 AT 2:35 AM

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