replaced heads now all it does is back fire

2000 MAZDA B3000
180,000 MILES
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FLMUDDER86
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  • 3 POSTS
Truck had blown head gasket and both heads where cracked. Replaced all with new and new heads. Truck just spins over and back fires out the exhaust and intake timing was never touched. Please help!!!!
May 6, 2013 at 7:56 AM
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WRENCHTECH
  • ✓Experienced Mechanic
  • 20,760 POSTS
Backfiring means the spark is occurring at the wrong time. That is most likely due to incorrect firing order, bad distributor cap (if it has one), bad coil, ignition module or crank sensor. You may need a lab scope to look at some of those circuits.
May 6, 2013 at 9:11 AM
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FLMUDDER86
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  • 3 POSTS
I checked the firing order a million times so i know that is right i am going to check sensors in the am. Truck ran before heads where replace.
May 6, 2013 at 9:39 AM
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WRENCHTECH
  • ✓Experienced Mechanic
  • 20,760 POSTS
The problem is going to be somewhere in the ignition system.
May 6, 2013 at 9:42 AM
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FLMUDDER86
  • MEMBER
  • 3 POSTS
What sensor do recommend i start with?
May 6, 2013 at 9:46 AM
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