Thread: Needng some help with some fuel sending unit and pump issues

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hey guys ...Noobie here but been a GM man all my life...question 1-my 1989 gmc 1500 was originally a TBI well over the years it hyas become a carb. motor ...muy question is can i pipe in my stock fuel sending unit and pump to my carb ? or do i need an electrical pump ? i have no other issues but that...please give a dog a bone ...been fighting this to long

Welcome to CHR, Steve. If your truck was TBI doesn't it have an in-tank electric fuel pump? You can use that just fine, but you'll need to put an in-line pressure regulator on it to reduce the pressure to around 3-5psig. I think your TBI setup ran 9 to 13psig, which is too much for your carb.

Welcome to CHR Steve:

The fuel pressure for the TBI is between 12 and 15 psi – way too high for a carburetor. You’ll need a regulator to bring your pressure down to 5 psi - a fuel pressure gauge mounted near the carburetor is a good idea. On the sender unit, the fuel line is 3/8", the vent is 5/16" and the return is 1/4". The fuel and vent lines are re-used and the return may be capped.

Summit Regulator - SUM-G3131-1, $24.95 One in and two out ports (Carb and gauge, all 3/8" fittings)
Summit Oil-Filled Gauge - SUM-800130, $17.95



Others with far more experience here will chime in!

Good Luck,
Glenn