1986 GMC S15 POPPING BACK THROUGH CARB

  • Tiny
  • kickinback47
  • 1986 GMC S15

Engine Performance problem
1986 GMC S15 6 cyl Four Wheel Drive Manual

bought an older truck that was not running, replace a worn timing chain and gears which got the truck running again, also replaced the fuel pump, fuel filter, plugs, wires, cap, rotor, and control unit in the distributor, all of this made the truck run better but I am getting a poppin noise which sounds like it is comming from the carb. Is there anything else I should try before I pull the heads or cam. After replacing the timming chain and gear the truck started the first time I tried it and idles fine but when you give it some gas the popping gets louder. Any ideas?

Wednesday, April 14th, 2010 AT 4:24 PM

1 Answer

  • Tiny
  • hmac300
  • Expert
  • 42,119 posts

A bent or broken pushrod will cause this as well as a burnt inlet vavle Or bent valve. Take your valve covers off and check. If everything is ok then you'll have to check your compression and your lifters.

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Sunday, April 18th, 2010 AT 5:30 PM

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