3.6 LFX Fuel Pump Question

Wendell #527

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I'm running a Chevy 3.6 LFX V6 out of a 2014 Camaro in my buggy. The high pressure fuel pump makes a loud chirping, almost sounds like a loud squeaking. That hi press fuel pump is fed by a high volume fuel pump that pushes fuel up to the hi pressure pump that's on the motor from the fuel cell. I'm concerned the squeaks might be cavitation in the hi pressure pump and it will eventually fail. It dynos good now but I need it to dyno good after 1360 miles. Does anybody have any idea about this?
 
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Wendell #527

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I was wondering about that. Would you put a gauge between the low pressure pump and the hi pressure pump, or would you tap into the hi pressure lines after the hi pressure pump and look at it there? Or both?
 

dzrt performance

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I was wondering about that. Would you put a gauge between the low pressure pump and the hi pressure pump, or would you tap into the hi pressure lines after the hi pressure pump and look at it there? Or both?
both. just use caution on the high pressure side to get a gauge with appropriate scale for the expected pressure you are running.

also just because it seems stable at idle doesn't mean it is under load or bouncing around in the desert.
 

Wendell #527

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Thanks. I suspect that noise is indeed cavitation. I will install gauges and likely increase the pressure feeding the hi pressure pump and see if the cavitation stops.
 

JDDurfey

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I know you are working on a gas engine, but this issue is also common to diesels and many times shops go straight to the high pressure pump thinking there is a problem with it, and they don't properly diagnose the low pressure delivery pump. If the high pressure pump is not getting "fed" properly then the performance will suffer because the high pressure pump is cavitating.

Pressure gauges are a great idea, but like said, you need to watch them in a "real world" scenario. We had a fuel pressure problem once and thought it was the pump, but instead we had a pick up tube issue in the fuel cell that was sucking air and causing all our problems.
 

Wendell #527

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Good point JDD. Another thing I boned up on was removing the foam insulation from around the hi pressure pump. I should have left it there. I’m putting it back, plus I’m insulating the fuel lines further back with wrap. Engine heat from the fans was heating up the fuel lines, making it even easier to cavitate.
 
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