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Discussion Starter · #1 ·
Hey guys,

In my ongoing quest to find the issue I'm having of long starts and bogging down, I picked a fuel pressure testing gauge today.

After connecting it to the testing valve and starting it up, it's reading around 21 for the pressure which I know is low. Unplugging the vacuum line from the Fuel Pressure Regulator doesn't increase or change the pressure. Once I turn the key off, the pressure immediately drops to 0 on the gauge.

From what I understand it's supposed to maintain some pressure once it's turned off correct?

I have recently replaced the Fuel Pressure Regulator on the end of the fuel rail. Is this a sign of a bad pump or a piece on the pump?

Also when I turned the engine off and listened I could hear what sounded like something draining.

Any help would be much appreciated.
 

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Have you checked/changed the fuel filter yet? There could be a possible clog in the system, but unlikely. The fuel system is very basic, so if you already replaced the FPR and confirmed its working well then the only other mechanical component in the system is the pump. Everything else is either the 2 relays, (fuel pump and auto-shutdown), the pressure/feeder line, the inline fuel filter, and the return line back to the tank. That's basically the entire 2.5 fuel system, nothing fancy. My theory is that the pump is failing and causing a "leak-back" into the tank, which is why your pressure keeps dropping to 0, and yes it is supposed to maintain 25+ psi at the key-on position. Sometimes a failing fuel pressure regulator can get stuck in a semi-open position, causing a leak-back to the tank, but if you replaced it with a new one that shouldn't be an issue.

How old is the fuel pump by the way? Can you hear it prime when you key-on? Are you getting voltage back at the fuel pump connector? At least eliminate the electrical portion of it with the voltage check and maybe swapping the relays to see if anything changes, before you start dropping the tank and all for the pump change. I know it sucks changing the pump but it's definitely doable with the right tools, a second pair of hands, and plenty of ground time. That's the hardest part to change in the fuel system but usually is the highest suspect to most fuel problems. Just try to eliminate everything else before you get head deep in the pump swap lol.
 

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Discussion Starter · #3 ·
So I bit the bullet and decided to just change the fuel pump this afternoon. With a second set of hands and a jack it was a pretty painless swap.

It seems to have resolved both the issues I was having. Including the long starts and the bogging down in acceleration. After replacing the pump the pressure was reading 31 at idle and it was starting right up.

I also took advantage of having the tank down and gave it a good cleaning and cut off about 7 inches of the hose inside the tank giving it the 15 to 20 gallon mod.

Hopefully this was the fix that it needed. Thanks for all the help!
 

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Glad to hear you fixed the problem. I'm having long starts without the bogging down but I changed my pump a few years ago. Need to check the fuel pressure to see if that's what's doing it.
 

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Discussion Starter · #5 ·
Glad to hear you fixed the problem. I'm having long starts without the bogging down but I changed my pump a few years ago. Need to check the fuel pressure to see if that's what's doing it.
I got a fuel pressure test gauge for $19.99 at Harbor Freight. It will at least rule out the pump and pressure regulator for you.
 
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