Truck backfires when it gets up to temperature

1991 DODGE DAKOTA
116,000 MILES • 3.9L • 6 CYL • 2WD • AUTOMATIC
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CAMERON13255
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  • 3 POSTS
I put a new fuel pump onto my truck because the original one would leave me stranded until it felt like working. When I put the new fuel pump on I put a new filter on as well. After I did all that the truck seems to backfire and bog down when I go to accelerate. it doesn't seem to be electrical.
Jun 28, 2020 at 9:42 AM
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ASEMASTER6371
  • ✓Experienced Mechanic
  • 52,796 POSTS
Good evening,

Can you test the pressure from the pump? You need to make sure there is sufficient pressure on the system.

https://www.2carpros.com/articles/how-to-check-fuel-system-pressure-and-regulator

Backfiring is usually from a lean running engine.

https://www.2carpros.com/articles/engine-backfires-while-running

Roy
Jun 28, 2020 at 9:55 AM
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CAMERON13255
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I can but I honestly don't know how to from the pump. There's no strader valve for an attachment.
Jun 29, 2020 at 9:41 AM
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ASEMASTER6371
  • ✓Experienced Mechanic
  • 52,796 POSTS
You need to open the line at the fuel rail from the pump and install the gauge there. When you rent the tester, it has all the instructions for this procedure.

1. Fuel system pressure must first be released before performing this test.
2. Disconnect the 5/16 fuel supply hose from the engine fuel line. Connect fuel system pressure gauge between fuel supply hose and engine fuel line.

Roy
Jun 29, 2020 at 9:53 AM
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CAMERON13255
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What pressure should I be looking for?
Jun 29, 2020 at 11:06 AM
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ASEMASTER6371
  • ✓Experienced Mechanic
  • 52,796 POSTS
Key on, engine off, 14.5. Engine running, 14.5 pounds.

Roy
Jun 29, 2020 at 8:46 PM
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