When running the car 3

Tiny
MWILLIE73
  • 1994 PONTIAC FIREBIRD
  • 117,500 MILES

When running the car (3.4L V6, Auto) there is a noticeable intake backfire coming from the air intake tube. I have checked the spark (looks yellowish) and checked the input voltage at the ignition control module. It is two volts lower than battery output voltage (i.E. Battery is outputting 12.5 volts, and the voltage at the module is 10.5 volts). So, I checked voltage at the fuse (under hood) and it is at 10.5 volts too. Why would there be such a large drop? Is there a wiring diagram for power distribution for the fusible links, so I can trace out the wires and check all hidden graounds?

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Monday, November 12th, 2012 AT 1:57 PM

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Tiny
DOCFIXIT
  • EXPERT
  • 18,987 POSTS

Have ALT tested low voltage and yellow spark will cause missfire

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Monday, November 12th, 2012 AT 7:48 PM
Tiny
MWILLIE73
  • MEMBER

Alt is New (less thatn one year old), but I took it and tested it at a local auto parts store. It tested good. The voltage drop measure was taken with the engine not running.

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Monday, November 19th, 2012 AT 5:57 PM

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