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Unread 06-01-2009, 08:53 PM   #1
bjl95mustang
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Is this right for my fuel pressure?

I checked my fuel pressure and the fsm says 49 +/- 2 psi. At idle my gauge is erratic and bounces between 45 and 55 psi. I rev it up and it's not as erratic but it still moves between 48-52 psi.

Should the pressure be steady? I can feel it pulsing through the gauge.

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Unread 06-01-2009, 09:12 PM   #2
Mickey_D
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Fuel pressure is only checked with the ignition on, engine off. You will never get an accurate reading with the engine running.
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Unread 06-01-2009, 09:16 PM   #3
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Quote:
Originally Posted by Mickey_D View Post
Fuel pressure is only checked with the ignition on, engine off. You will never get an accurate reading with the engine running.
x2 fuel pressure varies when running.
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Unread 06-01-2009, 09:18 PM   #4
bjl95mustang
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The fsm says start the engine.

So it will move that much on a returnless system?

Back when I had my mustang I could dial in the pressure to an exact ammount.
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ZJ 98 5.2 LIMITED De-Badged

4.5" Lift: RE 4.5" springs,Iro rear 3.5 springs+1" spacer, RE shocks, All adjustable arms, IRO front track bar and HD bracket, Rear jks track bar, 1-Ton Steering, 242 tc, 33x12.5x15 GoodYear wrangler silent tires, 15" rock crawler rims, Aussie Locker For My 44A, 760X u-joint front axles.

Soon to come Lock Right Front Locker.

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Unread 06-01-2009, 09:20 PM   #5
Mickey_D
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Um, someone forgot to put the crack pipe down the day they wrote that page? :shrug:

Never have I heard of checking fuel pressure with it running. As a matter fact, on the Vortec engines the wildly fluctuating fuel pressure at idle can actually destroy a pressure gauge...


[EDIT] Ok, that is just too weird. I just looked at my 95 FSM and it says the same thing - 39psi with the engine at idle. How odd.
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Last edited by Mickey_D; 06-01-2009 at 09:31 PM..
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Unread 06-02-2009, 06:35 AM   #6
bjl95mustang
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So can someone on here hookup a pressure gauge to thiers and tell me what it does while running?
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ZJ 98 5.2 LIMITED De-Badged

4.5" Lift: RE 4.5" springs,Iro rear 3.5 springs+1" spacer, RE shocks, All adjustable arms, IRO front track bar and HD bracket, Rear jks track bar, 1-Ton Steering, 242 tc, 33x12.5x15 GoodYear wrangler silent tires, 15" rock crawler rims, Aussie Locker For My 44A, 760X u-joint front axles.

Soon to come Lock Right Front Locker.

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Unread 06-02-2009, 09:08 AM   #7
Redrum_1
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I had a fuel pressure gauge hooked up to mine and at idle it held steady at 44 lbs.
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Unread 06-02-2009, 06:14 PM   #8
bjl95mustang
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Thats what I needed to know. I think the regulator is going out.
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ZJ 98 5.2 LIMITED De-Badged

4.5" Lift: RE 4.5" springs,Iro rear 3.5 springs+1" spacer, RE shocks, All adjustable arms, IRO front track bar and HD bracket, Rear jks track bar, 1-Ton Steering, 242 tc, 33x12.5x15 GoodYear wrangler silent tires, 15" rock crawler rims, Aussie Locker For My 44A, 760X u-joint front axles.

Soon to come Lock Right Front Locker.

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