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Fuel Pump$700

swalkers

NAXJA Forum User
Location
rhode island
I have been having some trouble with my '00 XJ lately. Mostly prolonged statups, it cranks for a while before it actually fires. I brought it into the mechanic and had the fuel pressure checked out. It was running at 47-49 psi and dropped down to 8 within 5 minutes after the engine was turned off. Looks like the electronics were ok as was the regulator.

I am assuming that I am going to need a new fuel pump, and probably before winter in New England.

However, my mechanic quoted me $700+ to have it done. Seems a bit high to me? Any thoughts on other fixes I can try for the mean time? Im going to try some seafoam to see if there is an off chance that might help.
 
You're kidding me.

$700?!

What you have is likely a problem with the check valve, built into the fuel pressure regulator which is unfortunately mounted on top of the tank+pump on 97 and later models.

You can either mount a second check valve in series with the first, in the fuel line, or just live with it - do the "poor man's prime" (turn to run, off, run, off, run, off, start - wait a few seconds each time you turn it to run) or simply keep doing what you've been doing.

If you really decide you want it done, buy the parts and bring it up here. That's a 1-2 hour job with two people working on it.

Parts needed - 1x 4798 301 (fuel filter / pressure regulator / check valve assembly)
2x J324 0023 / 5210 0362AA (fuel tank mounting J-bolt - I keep these on hand at all times)
2x stainless steel 3/8 washers
2x stainless steel 3/8-16 nylock nuts
assorted hose clamps
 
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I might take you up on that. Im actually moving into Watertown MA now I started a job in Bedford about 5 months ago. My girlfriend is from just west of Worcester, a little town called Oakham that no one has ever heard of.
 
Oakham? Been there a couple times, only really remember it because of the "welcome to oakham" sign on rt122 on the way to the airport a friend of mine keeps his ultralight at.

Checked online and the fuel pressure regulator/check valve/filter assembly is only really available from the dealer and runs around a hundred+ bucks, BUT the whole pump assembly including a new sender, filter, pump, etc is $125 from rockauto, spectra premium part number SP7121M. To use that you'd probably also need a new gasket (OEM PN 5201 8808) and locknut (OEM PN 5200 5389) which are both available from quadratec for under ten bucks each from what I recall.
 
I'll do it for $650, but not a dollar less!

I did the fuel check valve install on my '01XJ and it's almost kind of scary how quickly the truck starts up. The slightest little bump over and the engine is rumbling. Sometimes I'd have to crank the thing over for 5-6 seconds to get it to fire. Sometimes it would just crank and crank and I'd have to manually prime the fuel like kastein described, above. I was lazy and bought a check valve kit on e-bay. Took me a couple of hours to install as I wanted it done right so I cut my steel fuel lines and spliced it in. The check valve I bought came with compression fittings on either end.

Note: Keep your mouth closed and wear eye protection. Gasoline doesn't taste good and doesn't feel good in your eyes.
 
^ X2 on that... I nearly ate some gas and definitely got a bunch of rust and crap in my eyes last night while pulling subieracer05's old gas tank out of his MJ.

Some people hate the 97+ plastic fuel tank design and the fact that the filter is on top of the tank, but I consider it more than an even trade for the fact that the tank is plastic and will never, ever rust out.
 
I like the plastic tank design for that reason and because it's not nearly as cold when you're under the truck with snow on the ground trying to wiggle it back into place.

I still had the packaging for my fuel line check valve. I guess I didn't order it on e-bay and I got it from here: http://fuelsender.com/fuel_line.html

Edit: No, I DID get it from e-bay. Here is a link to one: http://cgi.ebay.com/ebaymotors/Fuel...CKV7-/370389372884?pt=Motors_Automotive_Tools

I opted to go with this one because of the compression fittings so I could install it directly to my existing fuel line. I did not want to use rubber hoses and hose clamps...
 
I like the plastic tank design for that reason and because it's not nearly as cold when you're under the truck with snow on the ground trying to wiggle it back into place.

I still had the packaging for my fuel line check valve. I guess I didn't order it on e-bay and I got it from here: http://fuelsender.com/fuel_line.html

Edit: No, I DID get it from e-bay. Here is a link to one: http://cgi.ebay.com/ebaymotors/Fuel...CKV7-/370389372884?pt=Motors_Automotive_Tools

I opted to go with this one because of the compression fittings so I could install it directly to my existing fuel line. I did not want to use rubber hoses and hose clamps...

Doesnt look like they sell it off their website.
 
Does the pump make more noise than you would expect when running?

If it's quiet, has good fuel pressure (47-49 is absolutely fine), and runs great once it starts, you don't need a new pump yet, just the check valve.

I would however buy a whole new pump assembly off rockauto - it's about the same price as just the check valve and filter assembly is from the dealer, so you can yank the valve/filter assembly off the top, stick it on your existing pump assembly, and keep the rest as spare parts / murphy's law prevention till your pump actually does die.

EDIT: or add the second check valve in series and forget about the whole thing, then you/we don't even need to drop the tank.
 
My '96 was exhibiting the same symptoms as you're having. I was convinced that it was the check valve, as the pump sounded good, the poor-man's prime would get it going, and it had a perfect 49psi when idling and shortly after shutdown. However, I never left the gauge on it to see how quickly it lost pressure, and the next day, it was down to nothing. I was ready to pony up the big money to get a new pump assembly, but someone on here suggested that it might be an injector leaking down, and see if a fuel system cleaner might help. So, I got a can of BG44K, closest source is a Toyota dealer (yech), dumped it in, and it worked. The engine starts eagerly again, and an almost inaudible misfire at idle is gone. But, I have a feeling that it's just waiting for cold weather to really let me have it!

And, the $700 is almost reasonable. Seven years ago I was going through the same deal with our '98 ZJ. The local dealer was getting $1100, and ZJs were lined up for service. The pump motor alone was almost $300. I got rid of it shortly afterward, as after a few months, it was acting up again.
 
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Speaking of an external check-valve, I was told that if the fuel rail didn't have a return line, then you shouldn't use an add-on check-valve, as the rail doesn't have a regulator, and there's no way for pressure to bleed off. I would think that as you turn the key off, the pump stops running before the engine stops turning, but the injectors also stop, retaining pressure. As I said, it starts better, but still not as fast as some of the others. My '92 sits for long periods, so yeah, I expect it to crank awhile, but the '96 gets used just about every day.

I just checked the '96. It's been parked for 14 hours, no pressure on the rail. Maybe I will try an external check valve, if no one thinks it would be bad.
 
I see your point there. Once the engine shuts down, the heat from it will expand the gases in the fuel line and if it has nowhere to vent then bad things could potentially happen.

I haven't blown up yet, but I'm not going to say I'm not worried now...
 
Speaking of an external check-valve, I was told that if the fuel rail didn't have a return line, then you shouldn't use an add-on check-valve, as the rail doesn't have a regulator, and there's no way for pressure to bleed off. I would think that as you turn the key off, the pump stops running before the engine stops turning, but the injectors also stop, retaining pressure. As I said, it starts better, but still not as fast as some of the others. My '92 sits for long periods, so yeah, I expect it to crank awhile, but the '96 gets used just about every day.

I just checked the '96. It's been parked for 14 hours, no pressure on the rail. Maybe I will try an external check valve, if no one thinks it would be bad.
Odd... not sure I understand the reasoning here. The original check valve's purpose in life is to keep the pressure from bleeding off so that the engine starts quickly (i.e. fuel delivery line is still pressurized) so adding another when the first one fails to retain pressure shouldn't cause any problems IMO.
 
Odd... not sure I understand the reasoning here. The original check valve's purpose in life is to keep the pressure from bleeding off so that the engine starts quickly (i.e. fuel delivery line is still pressurized) so adding another when the first one fails to retain pressure shouldn't cause any problems IMO.

Right, but I'm not sure where the original check valve is in relation to the internal pressure regulator. If the check valve is before the regulator, it would still allow the pressure to bleed off from the heat of expansion of the fuel. Adding an external check valve after the pressure regulator basically takes the regulator out of the system.

Could be me thinking too much. I haven't studied the layout of the fuel pump so I'm not sure where the check valve and regulator are in relation to one another.
 
From the info I have the stainless steel can-like part on top of the pump assembly is the check valve, regulator, and filter all in one. I'll have to disassemble the spare 97+ sender assembly I have (not sure where it is right now, since I just moved recently) and see if I can verify this.
 
I got that little gem of info from Dodge intrepidnet, as I was trying to diagnose a no start/poor man prime condition in a '97 'Trep. (turns out it was the CPS, somehow a prime ritual/voodoo chant would stimulate the CPS into working, for a few months, till it took the Big Dump?). The consensus on that board was no rail-mounted regulator, no auxilliary check valve. But, if some here have used it...

What I'm thinking is maybe the check valve needs to be in line before a regulator, leaving the regulator to be the last device to protect against over-pressure at the rail. Putting a check valve in-line, on a '96+ means it's getting mounted after the regulator. It might be a great way to find an injector that's leaking down overnight, but I don't want a cylinder full of gas...
 
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