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Topic Review (Newest First)
04-01-2012 07:47 PM
DaveB99TJSahara Just dropped my gas tank today and replaced the entire fuel pump assembly. I got it at Advance Auto for like $175.00. I was having slow start issues where my Jeep cranked for a really long time then fired up. Sometimes when parked on a hill I would start it and it would run for a few seconds then crap out. I would have to start it a couple more times then it would run. Jerry is right about the fuel filter and the fuel pressure regulator. I was just going to replace the FPR on top of the tank but I have heard that doesn't always fix the problem and if you do all the work to drop the tank spend a little extra and just buy the fuel pump assembly and replace it all. What a pain it would be to have to re-drop the tank. It took me about 2 hours with a jack and tools from the garage. I sprayed the bolts with liquid wrench yesterday morning and let it soak in for a day before the job. It starts right up every time now and the job was not that bad.When i put the fuel pump in there was some type of filter on the bottom of the assembly that was totally black from i guess dirt and whatever, the new pump had the same white pad on the bottom. That is some type of filter but probably just to keep the pump from clogging with debris. Replace the fuel pump and the problem will go away.
03-31-2012 01:08 PM
Jerry Bransford The fuel filter is located inside the fuel pressure regulator that sits on top of the fuel pump. It has a positively huge surface area and was designed to be a lifetime fuel filter. So far, the Jeep engineers seem to be right about its lifetime design because they're sure not getting clogged up and causing problems.
03-31-2012 01:03 PM
DevilDogDoc
Quote:
Originally Posted by reel effort View Post
I hope that is wrong, seems like a system would have problems without a filtration system. I will try to find my manual
It does have a filter, it's built into the pump.
03-31-2012 01:02 PM
DevilDogDoc
Quote:
Originally Posted by Diverdown87 View Post
I agree with Jerry.
Manual and factory recommends to replace the ff and or fuel pump @ 100k. Let me tell you from experience @ 100010 mine quit working and left me stranded. $672 later and I was back in bidness.....
Buy a new one and do it your self. If I had had the time I would have and saved myself $600.. Needless to say I am at 67+K miles on the replacement. You bet your bippy I have a new one waiting in the toolbox in the jeep JIC...
I just finished reading the fuel system section in my FSM and it makes no mention of a change interval. That said, I have 164000 miles on my original pump and the only issue is the slow start mentioned above. Hmmm I suppose I should pull it out of there huh? Even though it has never given me a problem?
03-31-2012 08:36 AM
reel effort
Quote:
Originally Posted by BigTxRdnck
If I'm not mistaken, Jeeps (and pretty much all Chrysler products) don't actually have an inline fuel filter-its part of the pump unit which is in the tank right?
I hope that is wrong, seems like a system would have problems without a filtration system. I will try to find my manual
03-31-2012 12:50 AM
BigTxRdnck If I'm not mistaken, Jeeps (and pretty much all Chrysler products) don't actually have an inline fuel filter-its part of the pump unit which is in the tank right?
03-30-2012 10:30 PM
reel effort
Quote:
Originally Posted by Diverdown87 View Post
I agree with Jerry.
Manual and factory recommends to replace the ff and or fuel pump @ 100k. Let me tell you from experience @ 100010 mine quit working and left me stranded. $672 later and I was back in bidness.....
Buy a new one and do it your self. If I had had the time I would have and saved myself $600.. Needless to say I am at 67+K miles on the replacement. You bet your bippy I have a new one waiting in the toolbox in the jeep JIC...
I tired turning the key to start and waited a few seconds each time I started today and that helped it start right away.
How much is a new filter (estimate) and what is the process for doing it? Do I have to drop the tank?
Thanks
03-30-2012 12:57 PM
Diverdown87 I agree with Jerry.
Manual and factory recommends to replace the ff and or fuel pump @ 100k. Let me tell you from experience @ 100010 mine quit working and left me stranded. $672 later and I was back in bidness.....
Buy a new one and do it your self. If I had had the time I would have and saved myself $600.. Needless to say I am at 67+K miles on the replacement. You bet your bippy I have a new one waiting in the toolbox in the jeep JIC...
03-30-2012 10:58 AM
Skol-Vikes My 98 4.0L is the exact same. I did replace the starter a couple weeks ago. Simed to make a small difference. It starts right up the second try. I just bought the jeep a month or so ago and will be replacing my plugs and wires next. I did try a bottle of Lucas fuel treatment didn't seem to do much, other then make my check engine light come on for that half a tank.
03-30-2012 09:29 AM
Jerry Bransford This issue is normally caused by the fuel having drained out of the fuel rail next to the fuel injectors and back down into the gas tank. There are check valves inside the fuel pressure regulator and fuel pump assembly designed to keep fuel up in the engine for fast starts and when they leak, a slow engine start is the result. The added length of time to start the engine is how long it is taking the fuel pump to get fuel back up next to the fuel injectors where it is normally supposed to stay to enable a fast start.

Replacing the fuel pump and fuel pressure regulator assembly is the fix. The fuel pressure regulator is the most common fix but sometimes it's the fuel pump as it was the last time I had this issue (I've had it in two different TJs). You can temporarily help (not cure) the situation by cycling the key a few times, as suggested by GoldenSahara00 above, to cycle the fuel pump on a couple times so it can pump fuel up into the engine before you start the engine.
03-30-2012 09:26 AM
scot68
Quote:
Originally Posted by reel effort View Post
Hi all-
I just purchased my 98 Wrangler with the 4.0 I-6 engine. Seems to be a great machine for having 106k miles. Many times when I attemp to start the engine, it seems to crank for a while (longer than usual) before it starts. I stop and then try again and tap the peddle, not sure if that does any good since it is fuel injected but it will start.
Any ideas on what could be the problem? Perhaps spark plugs or fuel pump? I recognize I haven't provided too much info here but I figured I'd ask.
Thanks
Very common with the 4.0L. Bad fuel pressure regulator (on top of fuel pump) or fuel injectors are two common causes of the condition you described. Either the regulator is allowing fuel to drain back into the tank (with engine off) or fuel injectors are bleeding (leaking) down.
03-30-2012 08:54 AM
OldBlue97 Also, it may just be OldBlue, but I have checked, cleaned, and replaced when needed just about everything on the ignition side and he still cranks for a bit longer when cold.
03-30-2012 08:52 AM
OldBlue97 I have the same scenario with my 97. I second Golden Sahara. When my Jeep is cold I simply turn the key on for a few seconds and then crank. Makes a world of difference. Of course, you do eventually want to check fuel filter, plugs, injection....blah blah...basic maintenance stuff for our older rides.
03-30-2012 07:09 AM
VoodooShot
Quote:
Originally Posted by bullind0
mine did that and it was due to having to build up a certain amount of oil pressure before it started
Fuel pressure not oil .
03-30-2012 06:03 AM
bullind0 mine did that and it was due to having to build up a certain amount of oil pressure before it started
03-29-2012 10:18 PM
GoldenSahara00 Turn your key to just before the on position. Let all systems come on. The pump will cycle or whatever. Then turn the key to start. Only takes like an extra second. I usually do this when it's cold. But sometimes it just doesn't like to start first or second crank like your saying. Try it out.
03-29-2012 10:15 PM
Blackpony04 My 99 used to slow start until the starter finally kicked the bucket and when it was replaced it was night and day. Check underneath and if the starter looks original, replace it before it strands you. Not saying it's not something else but it's a common slow start culprit. Also, a dirty or faulty IAC valve can cause similar issues too (and pumping the gas CAN make a difference if your IAC is crapping out).
03-29-2012 10:10 PM
trainsktg It sounds like something basic like a clogged fuel filter or old plugs. If the maintenance history of the vehicle is not known to you, I'd recommend performing all of the basics whether potentially related to this hard start problem or not by replacing all fluids and filters, installing new plugs and plug wires, and checking tire pressures and battery condition. I'd do all of these things before digging into deeper problems like fuel pumps, etc.
03-29-2012 09:19 PM
reel effort
98 TJ 4.0 question

Hi all-
I just purchased my 98 Wrangler with the 4.0 I-6 engine. Seems to be a great machine for having 106k miles. Many times when I attemp to start the engine, it seems to crank for a while (longer than usual) before it starts. I stop and then try again and tap the peddle, not sure if that does any good since it is fuel injected but it will start.
Any ideas on what could be the problem? Perhaps spark plugs or fuel pump? I recognize I haven't provided too much info here but I figured I'd ask.
Thanks

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