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low fuel pressure, starting problem

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Old 04-10-2014, 04:40 PM
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Default low fuel pressure, starting problem

So I have a 96 XJ with about 200k on it and I'm having the same problem that many have posted on (having to cycle the key a few times before cranking over the engine). My model has the fuel pressure regulator with the pump in the module inside the tank. A few months ago I replaced the fuel filter in hopes it was that so I didn't have to get into the tank, but I ended up replacing the fuel pump and pressure regulator when I dropped the tank. I put in a bosch pump, but the issue started again and I have to prime the line before cranking over the engine every time I start the car. I read that in my '96 jeep there's actually a check valve in the pump, but I'm not sure. I'd rather not have to get back into the fuel tank, but I'm worried I may be left stranded someday. I checked the fuel rail, barely a drip of gas flows out after I leave it overnight but when I prime it the pressure increases drastically. I'm not going to go with an external check valve after reading other posts since my XJ doesn't have a separate return line, but I am wondering what may be the issue. I just replaced the pump, regulator, and filter!

I've studied a few previous threads:
https://www.cherokeeforum.com/f2/inl...acement-87950/
Old 04-10-2014, 06:24 PM
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I would use a fuel pressure gauge to see what's actually going on. Rent one from an autoparts store if possible. Check to see what the pressure is while running, then shut the engine off and see if the pressure holds or drops. Sounds like a check valve to me though.
Old 04-10-2014, 06:41 PM
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It can be a bad check valve but it can also be leaking injectors causing you to loose the pressure.
Old 04-12-2014, 02:56 PM
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thank you for your comments. I should've mentioned that I also replaced the MAP sensor in my Jeep prior to replacing the fuel pump and regulator.

I'll plan on renting a gauge from an auto parts store and post an update with what I find. we have a new born in the home so she's taking precedence these days.

I was wondering if it could be leaky injectors, but wouldn't that cause the car to have a really hard time starting because the cylinder would be soaked in gas?

Thanks again
Old 04-13-2014, 08:19 AM
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A decent test gauge is only thirty bucks or so on Amazon.
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