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Discussion Starter · #1 ·
I just bought a 61k mile old 2004 TJ with the 4.0 and 5 speed. (Yeah, I stoked!).. I've had 5-6 jeeps through the years but have been away from them for several years. I'm thrilled to be back.

Anyway, this one runs/rides perfectly. But, after it's sat for a while (even like at lunch), it is very difficult to start. It spins the starter like crazy, but no cranking... Try, wait, try again, wait, etc - after a couple of tries it fires up and runs great. After it's running, I can shut it off and it will restart immediately.

I'm no mechanic, so I'm kinda lost here. Could it be something like fuel draining away from the injectors and taking a while to pump fuel back through the lines? (I also have a resto-mod 54 Olds with EFI and you have to have the ignition on for 4-5 seconds to give the fuel pump time to pressurize the lines before it'll crank)
 

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Discussion Starter · #3 ·
It turns over - just won't fire. Don't know if it's lack of fire or lack of fuel... It did this on my test drive, and previous owner said he pumped the throttle a time or two before trying.. that isn't working for me, and sounds more like a carb fix than a FI fix anyway LOL
 

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There's a few threads going right now about these same symptoms. I can only say get a fuel pressure guage and see what you have for fuel pressure at the rail. Ck it with just the key in 'run' position, then ck with engine running, then while driving. Then shut engine off and see if system holds pressure or it bleeds off. This test should rule out or condem the fuel pump
 

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Should be 49 but probably check valve in tank pissing away pressure

Try 3 or 4 cycles of key on then off each cycle raving on on for 3-5 seconds each cycle

That will give several priming fuel pump runs to overcome low pressure

If that works it will get you by for a while till you can replace the fuel pump/check valve/regulator unit in the tank
 

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Discussion Starter · #7 ·
Digger I've only started it once since reading this, and your suggestion definitely helped. I'll do a little more testing, but just in case, how hard is it to drop the fuel tank on an 04?
 

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It might be the seals on your fuel pump. I have the exact same problem, when jeep sits it takes a while to start. Try this, turn key but do not start, turn off key, turn key on again and try to start. If this works, its the seals in your fuel pump. Every time you turn the key on, the fuel pump runs for a few seconds charging the fuel rail.
 

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I believe there is a valve in the fuel pump assembly that is meant to hold the fuel in the fuel lines/rail, however it is known to go bad and leak. This is why cycling the key a few time helps, because you're building pressure back to the lines and rail. I had the same problem. Solution was to replace the fuel pump.
 

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I just replaced my fuel pump and am having this problem as well, my thinking is that I have air in the system and that is causing the issue. I had the key in the on position and checked the rail and air came out, after a few seconds fuel came out with plenty of pressure. This weekend I will drop the gas tank again and check the seals to see if that is the issue.

EDIT: I did replace the fuel pump only, not the entire assembly
 

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EDIT: I did replace the fuel pump only, not the entire assembly
My guess is that the valve/sending unit on top of the pump, which I spoke of in a previous post, is bad if you replaced the pump only and now you're having these issues. If there was any air in the fuel lines, it would purge when you tried to start it and the lines/rail filled with fuel.
 

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My guess is that the valve/sending unit on top of the pump, which I spoke of in a previous post, is bad if you replaced the pump only and now you're having these issues. If there was any air in the fuel lines, it would purge when you tried to start it and the lines/rail filled with fuel.
Are you referring to the regulator that is located on top of the fuel tank? Would be a relatively easy fix for this annoying problem, I am getting to be a pro at dropping the fuel tank. I can have it down in about 20 minutes.....
 

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Hahah yea that's what it is I'm referring to. That would be my guess for fixing your problems. But I'm sure others will chime in if in wrong.
 

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Discussion Starter · #15 ·
Looks like the sweet spot for getting mine to start immediately is 3 cycles of switch on, count to 3, switch off - then it'll fire right up. So, could be pump, valve, or seals apparently.
 

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Discussion Starter · #16 ·
Talked to a guy at Advance Auto to price fuel pump - when I described the situation he mentioned that the valve is in the fuel pressure regulator (which is much less expensive than the fuel pump). Where is the fuel pressure regulator located? Is it easier to get to than the fuel pump?
 

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Nope the check valve and regulator reside with the fuel pump inside the fuel tank

Typically replaced as one unit but can be gotten separately
 

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Discussion Starter · #18 ·
Local Jeep dealer says pump assembly (he couldn't verify what all is in that assembly ??) is $350 - labor to install is another $322.

Guess I'll be trying this install myself - but does $350 sound reasonable at all for the pump "assembly"?
 

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Many had good luck with Bosch units which can be had closer to 100

Many had bad luck with auto zone ones so unless you cut a hole in back floor to replace without dropping tank I would stick with Bosch or OEM

There are online places to check For best price on OEM
 

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Should be 49 but probably check valve in tank pissing away pressure

Try 3 or 4 cycles of key on then off each cycle raving on on for 3-5 seconds each cycle

That will give several priming fuel pump runs to overcome low pressure

If that works it will get you by for a while till you can replace the fuel pump/check valve/regulator unit in the tank
Ditto. I have to cycle mine 3 to 4 times then it starts right up. Just haven't gotten around to dropping tank.
 
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