1989 4.3 backfiring.HELP

[slowridinS10]

I have a 89 4.3 with T.B.I..I had a bad TBI so I replaced it with a Holley 670 cfm TBI unit and it still is backfiring through the TBI.I need help please..........................Slowridins10

[T Man]

Sounds like a timing problem to me. Too much retard(?)

[Sparky2263]

Yup. Retarded timing will do it every time.

[rat]

I'd check the timing first like they said^^^ Don't forget to disconnect the computer controlled brown wire thing before setting it. It should be under the passenger side carpet up under the dash.

But, running lean can also cause it to backfire through the intake manifold.