1984 C4 Fuel Pump Noise
Thread Starter
Drifting
Joined: Mar 2006
Posts: 1,263
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From: Wabasha Mn
1984 C4 Fuel Pump Noise
Have an 84 C4 with carb conversion. Original fuel pump and have had no problem for 8 years. Have a mallory FPR and engine runs fine at 5 psi. Started engine yesterday and heard a "thumping" sound from the pump that quit after 10 seconds or so and after engine warm up there was no more thumping sound. I do have an oil pressure switch for the pump but also have an overide toggle switch under the hood and turned it on this morning and the thumping sound ( about 1 thump every 1-2 seconds) was still there with engine cold. Guess it is time for a new pump??? What do you guys think?
Zen Vet Master Level VII
Joined: Mar 2016
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From: Southlake, TX
Drifting
Joined: Aug 2019
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The electrical test would be to check fuel pump current draw when it makes the noise vs quiet. The guts are ceramic, and they do wear. But then it would show up as a larger current draw,
A noisey pump is on borrowed time. Don't wait too long if you determine that it' s bad.
A noisey pump is on borrowed time. Don't wait too long if you determine that it' s bad.
