Filter head fuel pressure with Fass/spikes? - Chevy and GMC Duramax Diesel Forum
01-04.5 LB7 Duramax Powertrain Discussion of components that are directly involved in the power production and all that is needed to get and keep the truck moving . Engine , Transmission, Etc.

 
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post #1 of 5 (permalink) Old 05-19-2019, 01:53 PM Thread Starter
 
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Filter head fuel pressure with Fass/spikes?

I just replaced a cp3 (again) after the last O'reilly reman unit I installed blew the shaft seal after 300 miles and filled the crankcase with fuel. I installed a fuel pressure gauge at the stock fuel filter head bleeder screw to monitor the pressure on the off-chance that some sort of pressure issues blew the cp3 seal. The gauge reads 6 psi consistently then will randomly spike to 10psi then immediately return to 6psi. Is this pressure correct? Are spikes like this normal? Is there a better place for the fuel pressure sensor?
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post #2 of 5 (permalink) Old 05-19-2019, 02:45 PM
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The fass should have a port to read pressure also. Or can use the Schrader valve on the motor. Whens the last time the filters were changed? Also that spike wouldn't hurt the cp3

Nic
2011 GMC Sierra 2500 cc/sb LML Quicksilver
Has some stuff to make it go fast and blow up sooner.
2 Banks performance dpf's, 2.5 egr coolers, 3 Def tanks filled with meth, custom hot air intake, snail mod,
garden hose ran from fass, 16 John deere injectors, 22x16-378 forces, and like sooo many stickers brah

Wiles Diesel Performance
Woodstock, Va

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post #3 of 5 (permalink) Old 05-19-2019, 03:07 PM Thread Starter
 
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The Fass filters are about 3000 miles old and the engine bay filter was changed right before the test drive. I completely forgot about the Schrader valve. I have a mechanical gauge lying around, I'll get that hooked up and make sure they agree.
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post #4 of 5 (permalink) Old 05-19-2019, 03:27 PM
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High lift pump psi wont affect the cp3. It will throw off the reg and give you a lope though. I know guys who run much higher than the recommended 8 to 12 psi. The older trucks like yours the higher psi affected the ficms.

Nic
2011 GMC Sierra 2500 cc/sb LML Quicksilver
Has some stuff to make it go fast and blow up sooner.
2 Banks performance dpf's, 2.5 egr coolers, 3 Def tanks filled with meth, custom hot air intake, snail mod,
garden hose ran from fass, 16 John deere injectors, 22x16-378 forces, and like sooo many stickers brah

Wiles Diesel Performance
Woodstock, Va


Last edited by SilverGorillaLML; 05-19-2019 at 03:35 PM.
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post #5 of 5 (permalink) Old 05-19-2019, 08:59 PM Thread Starter
 
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Yeah, its been running like a top . Must have just gotten "lucky" with a bad reman. Thanks for the input.
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