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Unread 06-28-2009, 09:55 PM   #1
wmeyer116
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why is it taking longer and longer to start?

So recently my tj has been been taking a while to start. It turns over fine, but it just takes a really long time.

sometimes it is faster if i turn the key and let it try for a few seconds, stop, then turn it again, and it will start eventually.

when it actually does start, it kinda sputters at first and has trouble getting up to an idle, but then a couple of seconds later it does just fine, and everything is normal.

spark plugs only have a couple thousand miles, air filter is brand new

ideas?

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Unread 06-28-2009, 10:01 PM   #2
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its a fuel pressure issue, do a search on it and you should be able to find it. there was a pretty good thread about it and key things to check just the other day.

basically, your fuel pressure is leaking down while the jeep is sitting and it takes a minute to build the pressure back up to 'start' the jeep. that is also why it sputters. most commonly the pressure valve goes bad and lets the fuel drain back into the tank. you can leave the key forward for a second or two before trying to start it to allow the fuel pump to build up pressure before you try and start it.
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Unread 06-28-2009, 10:06 PM   #3
wmeyer116
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really? how hard is it to replace the valve?
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Unread 06-28-2009, 10:25 PM   #4
little_Jeep
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I think this is the thread that Panda is talking about........

http://www.jeepforum.com/forum/f9/starting-issues-cranks-few-times-before-fire-710025/
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Unread 06-28-2009, 10:41 PM   #5
DanaJeepTech
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I would connect a fuel pressure gauge and take a reading. Normal fuel pressure running is between 44 and 54 psi. After shut down you want to maintain atleast 24 psi after 5 minutes. If you are leasking down faster, fuel is either flowing back to the tank through a bad pressure regulator or through a stuck open injector.

Later model TJ's (2000-2004) had an issue with injector number three where fuel vapor would get trapped in the injector from exhaust heat. You would get a pretty noticiable misfire for the first minute after a hot soak and I had seen where it cause a longer crank time too although that was less common.

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Unread 06-29-2009, 06:11 AM   #6
TheBoogieman
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Leaking anti drainback valve.http://dailydriventj.com/fuel_pump.shtml
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Unread 06-29-2009, 09:19 AM   #7
jgorm
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Sometimes we remove the anti drain back valves (pprv) on high powered mustangs (its a major restriction and we get almost another 10% duty cycle, as well as removing a hesitation issue). The key is to turn the key to on for about 2 seconds before starting. If you are on a hill (nose up) then you can turn the key to on, off, on, then start and it will prime the system faster.
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Unread 06-29-2009, 10:27 AM   #8
Scotch740
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That was the first sign of my battery dieing.

To determine if the fuel drain back is the issue turn you key on for a few seconds (5 or so). That lets your fuel pump prime the fuel. Then try to start it. If that is the problem your jeep should start right up.
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Unread 06-29-2009, 11:29 AM   #9
Jerry Bransford
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Quote:
Originally Posted by jgorm View Post
Sometimes we remove the anti drain back valves (pprv) on high powered mustangs (its a major restriction and we get almost another 10% duty cycle, as well as removing a hesitation issue). The key is to turn the key to on for about 2 seconds before starting. If you are on a hill (nose up) then you can turn the key to on, off, on, then start and it will prime the system faster.
Removing that check valve would allow all of the fuel to drain back down into the fuel tank and in the TJ's case, turning the key on two seconds before turn it to Start won't be nearly enough time to get the fuel back up to the fuel injectors. Removing that check valve would be a bad idea in the TJ's case.
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Unread 06-29-2009, 11:41 AM   #10
jgorm
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Quote:
Originally Posted by Jerry Bransford View Post
Removing that check valve would allow all of the fuel to drain back down into the fuel tank and in the TJ's case, turning the key on two seconds before turn it to Start won't be nearly enough time to get the fuel back up to the fuel injectors. Removing that check valve would be a bad idea in the TJ's case.
I don't know too much about the jeeps fuel pump, but all the fuel drains out of my lines on the mustang too (pressure drops to 0 within 1 sec of key off). But then i have 2 high powered pumps and 2 sec of key on before starting works every time. I just gave this as a suggestion that it won't really cause any trouble if the OP doesn't fix it, other than a harder start and possible rough running for a few seconds.
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