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Topic Review (Newest First)
03-06-2014 08:17 PM
Insanityhunter Did you ever solve your problem? Mine was doing same thing it only did it if the jeep sat over night or for a few hours but as soon as i replaced with a new fuel pressure regulator (which blew air through both sides) it got worse and does it every time i try to crank it pretty much. also when i hooked up a fuel pressure gauge the only time it held pressure was when the jeep was idling and it held at about 50, if i just turned the key to on position is would only reach about 10 and instantly fall back down. Also when i turn the vehicle off the pressure instantly falls from 50 to 0.
12-31-2013 07:26 AM
tangofox007 JWT, the rail-mounted FPR is much less problematic than the TJ version. (I have a 26 year-old XJ with the original regulator still working fine.)
If you haven't yet solved your problem, you might check to see if your YJ regulator is passing gasoline to the vacuum port. That would be one clear indication of failure.
12-31-2013 07:07 AM
johnwiththree Thanks Jerry this has saved me a ton of money and time. I apreciate the reply and the help.
12-31-2013 06:46 AM
tangofox007
Quote:
Originally Posted by adodge View Post
Just because you can blow through both sides tells me that's not enough pressure to close the check valve. My 97 Tj is doing the same thing. I will most likely replace pump and reg assy.
There is no check valve in the FPR. That check valve is in the fuel pump. The drainback problem usually occurs because the pressure relief valve fails to seal completely and allows fuel to bleed back into the tank. In theory, the fuel pump check valve could fail with the same result, but the odds severely favor a failed FPR.

Despite claims to the contrary by folks who know a little about a lot, there is no mechanism in the FPR itself that provides for one-way flow. Fuel will flow with equal ease in both directions, I guarantee it.
12-30-2013 09:15 AM
Nuke Worker Check part 24 from this link. Please correct me if I'm wrong but a filter you can blow thru both end.

Fuel System Parts - Tank Fuel, Gas Cap, Injector Fuel, Throttle Body, Idle Speed Motor and Sensor Throttle Position for your Jeep Wrangler TJ by Morris4x4
12-28-2013 05:41 PM
adodge Just because you can blow through both sides tells me that's not enough pressure to close the check valve. My 97 Tj is doing the same thing. I will most likely replace pump and reg assy.
12-28-2013 05:33 PM
Jerry Bransford Not being a YJ guy, I believe your '95 4.0L has its FPR on the fuel rail. I wish the TJ's was!

Yours should look like this...
12-28-2013 05:03 PM
johnwiththree This thread is great. I have a 95 and having this exact problem. Does anyone know if the FPR on the 95 is also in the tank or is it up front? My problem is getting worse so I will need to tackle it now. Thanks this has been very helpful.
08-11-2013 05:52 PM
Jerry Bransford My Spectra fuel pump & FPR lasted about a year before it started letting the fuel drain down out of the fuel rail. I now have to cycle my ignition switch 6-8 times to get fuel back up to the fuel rail so the engine will start. I installed the Spectra out of low funds desperation, I'll be replacing it with an OE Mopar asap.
08-11-2013 04:33 PM
ChaddG ok, so.... your fuel pressure was low... that means the fuel pump itself is gone/going.
if your fuel pressure is high it means your regulator.
normal pressure is 45-54 psi. <according to the haynes> I replaced my whole fuel sending unit with one from spectra premium. Got it off amazon.com. cost me 120.00 free shipping. comes with a new everything. even the rubber gasket that seals the ring to the tank. I had to replace my tank skid, so I replaced that while I was down there too. also the straps. <looking back I should have done the rear track bar too >
08-11-2013 04:01 PM
Dlwmorgan So I just changed my FPR and still have the problem to crank the ignition a few times to get it started. And by a few times i mean like 20-30 minutes. Are there any other solutions? I am going to replace the spark plugs to see if that helps even though I just changed them not to long ago. I'm out of ideas on what the problem is. Could it be the crank sensor? Any help would much appreciated!
07-09-2013 11:34 AM
tightlines
Quote:
Originally Posted by tightlines View Post
Okay, I have been having similar issues. Just ordered an new FPR and hopefully I can get-R-dun as soon as the part comes in. Thanks for the info Jerry. I will post the results of my efforts.
Installed the new PFR over the weekend and it works like a dream. Fires right up! Took around 3.5 hrs total.
06-24-2013 05:55 PM
tightlines Okay, I have been having similar issues. Just ordered an new FPR and hopefully I can get-R-dun as soon as the part comes in. Thanks for the info Jerry. I will post the results of my efforts.
01-20-2013 11:03 AM
T.C.S TOY
Quote:
Originally Posted by Jerry Bransford View Post
It can be done in an hour and you only need basic hand tools and a jack to do it. Just make sure the tank is nearly empty before you start the job.

This is what the top of the tank and fuel pressure regulator looks like, which just snaps into place, I replaced mine earlier this year.

Great post up Jerry,thanks as iam having some problems with mine i think as well.
09-20-2012 07:06 PM
tangofox007
Quote:
Originally Posted by BigGreenMachine View Post
Is this guy ^ always arguing with you Jerry?
I am not arguing with Bransford. I am just telling him in no uncertain terms that he is wrong.
09-20-2012 07:03 PM
BigGreenMachine Is this guy ^ always arguing with you Jerry?
09-20-2012 06:59 PM
tangofox007
Quote:
Originally Posted by Jerry Bransford View Post
The FSM os wrong? Uh huh, whatever you say.
I am not the individual telling people that their regulators are defective because they pass air both ways. Or that air is not viscous enough to actuate the "check valve."
09-20-2012 06:52 PM
Jerry Bransford The FSM is wrong? Uh huh, whatever you say.

Edit: Oh nice edit to delete where you just claimed the FSM was wrong.
09-20-2012 06:48 PM
tangofox007
Quote:
Originally Posted by Jerry Bransford View Post
Go argue with the FSM.

Not everything in the FSM is correct.
Fact is, the FSM does not state that there is a check valve in the FPR.
09-20-2012 06:44 PM
Jerry Bransford Go argue with the FSM.
09-20-2012 06:35 PM
tangofox007
Quote:
Originally Posted by Jerry Bransford View Post
You're just being argumentative... that "relief mechanism" is a relieve valve (valve is the word you used for it elsewhere) which also serves as a check valve.
Despite FSM wording to that effect, the relief valve does not truly serve as a check valve. If it did, a regulator that flows backwards (not the same as leaking though the relief valve) would be as defective as you claim it is.

Fuel entering the regulator has two ways to get out. One of those options should be unavailable below about 50 psi. Unless it leaks.

Quote:
Originally Posted by Jerry Bransford View Post
Reasonable people who aren't just trying to be argumentative simply call it an anti-drainback valve since when it works properly, it prevents fuel from leaking around the FPR and back down into the gas tank.
Knowlegable people understand that the anti-drainback valve is in the pump assembly, not the fuel pressure regulator.

Reasonable people don't invent theories that happen to fit the circumstances and them preach them as gospel.
09-20-2012 06:07 PM
Jerry Bransford You're just being argumentative... that "relief mechanism" is a relieve valve (valve is the word you used for it elsewhere) which also serves as a check valve. When it leaks, it allows the fuel to drain past it and back down into the gas tank... as you even described in another of your posts today. Reasonable people who aren't just trying to be argumentative simply call it an anti-drainback valve since when it works properly, it prevents fuel from leaking around the FPR and back down into the gas tank.
09-20-2012 05:24 PM
tangofox007
Quote:
Originally Posted by jleahy View Post
I spoke to my jeep mechanic today and he told me the FPR is located at the fuel outlet under the hood and that the check valve is located on top of the tank. I have a 4.0 and am wondering if it's possible that just the FPR could be bad vs. the check valve or as someone posted, it would have to be both? Can someone clarify please?
Older Jeep models with the 4.0L engine ('95 and earlier) did have a FPR under the hood. Your FPR is at the tank, but there is no "check valve" per se in the FPR. There is a relief mechanism which tends to leak with age, allowing the fuel supply line to drain back into the tank via the relief passage.

There is a check valve in the pump assy, but the FPR is your most likely culprit. In the vast majority of cases, replacing the FPR will solve a "slow start" condition.
09-20-2012 04:43 PM
Jerry Bransford Your mechanic is wrong, the fuel pressure regulator which contains the anti-drain back valve is located on top of the fuel tank as described above.
09-20-2012 04:12 PM
jleahy I spoke to my jeep mechanic today and he told me the FPR is located at the fuel outlet under the hood and that the check valve is located on top of the tank. I have a 4.0 and am wondering if it's possible that just the FPR could be bad vs. the check valve or as someone posted, it would have to be both? Can someone clarify please?
09-05-2012 12:59 PM
obidya yeah, I think thats mostly the case.
the assembly is actually the same but early on in 97 they were still using the YJ plugs, they upgraded the plugs late in 97 and retrofit all pumps. the only options I have at the moment are.
1) splice the old wiring onto the new assembly
2) splice a new plug to the jeep side
3) buy a $50 wiring harness from jeep to convert old plug to new

I will likely just splice the wiring harness from the old into the new, unless I can find a reasonable adapter.. I really don't like those options but they will work.
09-05-2012 11:11 AM
Jerry Bransford VERY early '97 TJs often used 1995 Wrangler YJ parts, particularly electrical like sensors. You may need to use a fuel pump out of a '95. I had to use a '95 Throttle Position Sensor when I needed to replace it in my '97. The '97 TPS I first bought had a different connector than what my '97 had but the '95 TPS fit perfectly.
09-05-2012 10:56 AM
obidya as far as I know the only actual difference between the 15 and 19 gallon pump assembly is the fuel gauge arm. its shorter on the 15 because full is at a shallower spot on the tank.

one thing im trying to figure out... My 97 has a square plug, and all replacements seem to have a rectangular plug...

this is what mine looks like


It almost looks like a dodge dakota fuel assembly.. im so confused
07-12-2012 07:01 PM
arineod FYI

My 97 Wrangler TJ Sport build sheet states it has a 15 gallon tank and when I dropped the tank and pulled the fuel pump assembly I noticed that it was for a 15 gallon tank (Says it on the side). I bought the fuel pump assembly for the 19 gallon tank and it appeared identical in size compared to the 15 gallon pump I pulled. I threw the new pump in and it fit and worked like a champ. I also did the mod to cut down the breather hose as well. Filled up the tank and was able to get over 17 gallons in there.

From what I can tell, if you have a 15 gallon tank and need a new fuel pump assembly, just buy the one for the 19 gallon tank because it is cheaper, fits and works great. I was seeing the 15 gallon tank fuel pump assembly selling for almost $100 more in some cases. Some brands were only $20 more but why waste your money when you don't have to.
07-09-2012 06:36 PM
Jerry Bransford
Quote:
Originally Posted by Gorving3 View Post
I noticed RockAuto has 5 different brands of fuel pump assemblys ranging in price from $155 to $354. Bosch is the highest price one, does it really make any difference in quality and performance which brand/price a person gets?
I couldn't afford much when I needed one so I ended up paying $180 or so for a combination fuel pump/fuel pressure regulator a couple years ago from Rock Auto. So far it's doing fine in my '04 TJ. Unfortunately I don't recall its brand name. I was uncomfortable not buying the OE from the dealer but...
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