• NAXJA is having its 18th annual March Membership Drive!!!
    Everyone who joins or renews during March will be entered into a drawing!
    More Information - Join/Renew
  • Welcome to the new NAXJA Forum! If your password does not work, please use "Forgot your password?" link on the log-in page. Please feel free to reach out to [email protected] if we can provide any assistance.

New fuel pump, new regulator, still has fuel pressure issue..

Leaking down that fast does not sound reasonable for an injector. Or several. If it were injectors your oil should be full of gasoline by now. It should be simple enough to check the oil just with the dipstick. Maybe give it a good sniff too. If still in doubt you could change the oil. Then try to light the drain pan. Well, maybe not... :fuse:

I can't imagine the vehicle would even run well with injectors that didn't shut down.

I think revisiting the tank end of things is the best bet right now. The suggestion of trying to run the pump assembly outside of the tank is a reasonable one, if you can figure out how to do it safely.
How do i safely do that?

Sent from my Moto G (5S) Plus using Tapatalk
 
Ask BCKNBLK how he went about it. Or how he would go about it if he were to do it again.
 
Drop the fuel tank and give that assembly in there a very good look-over. You are describing the exact problem I had several years ago. Turns out the fuel pump/filter/float assembly had a leak on it. The pump worked fine, but there was a leak on the unit itself and was leaking fuel right back into the tank. Finally discovered this after taking it out again, and priming it off the vehicle. It started pissing fuel back into the tank. Thats where my pressure was going. Dropped in a brand new assembly (brand new), re-installed the tank, etc. Ran like a champ.
How would one go about this? I'm under my jeep with the assembly out and a cup of gas lol...

Sent from my Moto G (5S) Plus using Tapatalk
 
I'm thinking there is an internal leak at the fuel pressure regulator. I just haven't had enough of them apart to know what's missing. He's got both o-rings on the regulator. I thought there was a screen that spaced the small o-ring further into the socket. but that may be on a GM system.

I'm at a loss.





Edit: the screen I was thinking of is found on the Chevy Vortec 4.3's. (so it doesn't apply here)
 
Last edited:
How would one go about this? I'm under my jeep with the assembly out and a cup of gas lol...

Sent from my Moto G (5S) Plus using Tapatalk

I'd try a clean drain pan and enough gas to submerge the filter sock.
 
Low and behold i have progress who is still awake!? First a question... What SHOULD the system hold psi wise, and over what time period....instead of losing INSTANT pressure, it went fron 30 to 20 ish when i shut her down, than over the past half hour its down to 15... Now down to 12... I THINK it kight hold 12, ill explain what i found later on, but for now need the pressure answers please... I promise you WILL laugh ..

Sent from my Moto G (5S) Plus using Tapatalk
 
The little rubber hose at the bottom was leaking, i sat the sock filter guy in a cup of gas, ran the pump, and watched as gas trickled out of the bottom of the hose.... I added a better hose clamp and actually used two... It still lighlt lighty leaks just enough to notice its wet, is that normal? The hose and clamps are fine, and it holds 25 psi after shut down fine, than 15, than an hour later drops to 9/10 psi... SOO


, the 30psi during running to 0psi when switched off, was ALL THANKS TO A HOSE CLAMP!


IS IT ok that it SLOWLY bleeds down to 9/10psi or do i have a second issue at hand?

Should i keep buying different hose clamps till one leaks 0%? Lol
bc18f4ddcd48a5bc520eec7125de05a4.jpg


Sent from my Moto G (5S) Plus using Tapatalk
 
To clarify... Jeep had 30psi cranked, 0psi as soon as it was switched off.


The fuel pump in cup of gas

When cranked would leak, when switched off would leak

I put new hose clamps

Now when cranked it DRIPS ever so barely, and when switched off it leaks ZERO and pressure dies SLOWLY from 25 to 9/10 over an hour of time.

Sent from my Moto G (5S) Plus using Tapatalk
 
Im just being super nervous now that i found out the flowing hose was the issue, this clamps a LOT tighter, im just super anxiety over the fact ANY gas leaks from under hose LOL.
233fff4ffd5e61bd1c5ac4a503e1ffb6.jpg


Sent from my Moto G (5S) Plus using Tapatalk
 
The 30 psi is about right.

The leaking down is still not right. But, it is nice to see that you have made progress on that front.

A couple of details regarding that hose. First, make sure it is the correct type of hose. It should be SAE 30R10. If in doubt, you should be able to get that from a Napa auto parts (Linky: http://www.napabeltshose.com/~/media/napa/documents/napa-submersible-hose.pdf?la=en )

Second, get yourself some fuel injection hose clamps. I don't know that they are generally required inside the tank, but given the situation I would not hesitate to spend the $5 or so to get the best clamp possible for the job. FI hose clamps should do a better job.

Once you have things under control at the sending unit/pump assembly, if you still have a leak down situation, then go back to clamping off the fuel line to see if you are losing pressure at the injectors.

You may have more than one issue at play here.

ETA: Thank you for posting up your progress on the problem. All too often solutions are proposed but no follow up ever happens, and thus nothing is learned by the rest of us. And I am sure it is often really simple stuff, like that leaking hose, and no one wants to share something that others might think is stupid. I am certainly not laughing at you for a leaking hose that can't be identified without taking things apart and testing them outside their normal environment. Thank you.
 
Last edited:
The 30 psi is about right.

The leaking down is still not right. But, it is nice to see that you have made progress on that front.

A couple of details regarding that hose. First, make sure it is the correct type of hose. It should be SAE 30R10. If in doubt, you should be able to get that from a Napa auto parts (Linky: http://www.napabeltshose.com/~/media/napa/documents/napa-submersible-hose.pdf?la=en )

Second, get yourself some fuel injection hose clamps. I don't know that they are generally required inside the tank, but given the situation I would not hesitate to spend the $5 or so to get the best clamp possible for the job. FI hose clamps should do a better job.

Once you have things under control at the sending unit/pump assembly, if you still have a leak down situation, then go back to clamping off the fuel line to see if you are losing pressure at the injectors.

You may have more than one issue at play here.

ETA: Thank you for posting up your progress on the problem. All too often solutions are proposed but no follow up ever happens, and thus nothing is learned by the rest of us. And I am sure it is often really simple stuff, like that leaking hose, and no one wants to share something that others might think is stupid. I am certainly not laughing at you for a leaking hose that can't be identified without taking things apart and testing them outside their normal environment. Thank you.
I try to keep folks updated, especially when they take the time to help me. Plus i hate when i google a problem and there are countless forums left open ended. Im sure someone else has/will have this issue, and i hope this thread helps.

Do you know the diameter of the hose i need? They have a few options, i might swing by napa on my way home from work today. (I know the type of hose, not size)

This all adds up too, because the old pump and this pump did it, guess what? When i replaced the oreilly pump with the bosch pump i reused the rubber line that came with the oreillys pump. Who knew that 2 minutes saved of time would cause all this heart ache.

Those "fuel injection hose clamps", those are what the bosch pump came with, the oreillys pump had the average kind.

Last night when i found that leak i put the "fuel injection" hose clamp on it, and that helped the immediate pressure drop, but it still slowly dropped from 34 to 0 overnight. But it still slightly slightly SLIGHTLY trickles, but a slight trickle over 10 hours can cause 0psi, atleast i assume. Am i right?


SO hopefully its this stupid rubber hose. The one that came with the bosch is in its brand new zippy bag in my shed still, i bet that would solve this, but i mise well splurge on line at napa just incase.(if i can figure diameter out while being at work)

Thanks again a bunch!

Sent from my Moto G (5S) Plus using Tapatalk
 
If there is trickle then that is pressure slipping away. Definitely replace that hose if it isn't sealing up with the right clamps.

I don't know the hose diameter, and I would have to pull mine out of the tank to measure it. SWAG is 5/16", but I would want confirmation.

In theory the piece of hose that came with the pump should be the right stuff. I would at least expect Bosch to get it right. It would not surprise me if whichever chicom low bidder supplied O'Reilly's got it wrong. Given all the time you have into this thus far it would make sense to buy the known right stuff just to try to wrap this up for good.
 
My napa was out of line, i am going to swap the rubber line withthe one that came with the bosch, and make sure i have "fuel injector" style hose clamps on top and bottom.

Im doing this tonight, i highly believe its this pesky hose causing these issues,

Lets say its not, if all else fails, im jimmy rigging a check valve in line, just foe the weekend, is this safe? Ive heard it is and isnt... Mine is return style so i think it should be. Any good write ups? Im just asking incase it comes down to worse case. Id need diameter and parts to buy and who sells it retail wise.


Thank you so much guys!!

Sent from my Moto G (5S) Plus using Tapatalk
 
Well i found somewhere with the rubber line... Tried two times (the rubber line), and 4 different fuel injector clamps, no matter what i do itll still weep ever so slightly... Fixing to put an inline check valve and call it a dang day. Im uploading a video as im sure i sound uneducated over discussing a hose clamp and hose, but maybe it IS suppose to weap some? I imqgine not but no clue why it does no matter what. Any type of gas safe sealant I could use?
04c062f5a344b043a96bdc6abc547230.jpg


Sent from my Moto G (5S) Plus using Tapatalk
 
If there is trickle then that is pressure slipping away. Definitely replace that hose if it isn't sealing up with the right clamps.

I don't know the hose diameter, and I would have to pull mine out of the tank to measure it. SWAG is 5/16", but I would want confirmation.

In theory the piece of hose that came with the pump should be the right stuff. I would at least expect Bosch to get it right. It would not surprise me if whichever chicom low bidder supplied O'Reilly's got it wrong. Given all the time you have into this thus far it would make sense to buy the known right stuff just to try to wrap this up for good.
Sorry to spam, so to go along with my bad luck, the hose had an inner slit, i went and got more hose and the hose doesnt weap anymore.. talk about bad luck! Lmao

So it builds to 30 cranked, kind of bounces between 29-30

Than when off goes to 34, its dropped to like 32 over ten minutes... Lets see what it does overnight. If it reads 0 in the morning, in line valve it is!

Sent from my Moto G (5S) Plus using Tapatalk
 
I think you must have collected just about every failure mode possible with that little piece of hose.

Glad you finally seem to have the piece sorted out.

I doubt you will have 0 psi in the morning. If you are in the 20s I would say good enough. At this point I am betting your starting problem will be solved.
 
Is there way to "add friends" on here Anak? Youve been a big help.

Update on fuel issue... I went to the junkyard for an electrical piece today, and noticed that the fuel pressure regulator bracket looked different than mine... I snagged it and just got home, swapped it with mine, and low and behold at idle i went from 30psi to 50psi.... probably still have a bleed off issue knowing my luck this week.

But unless you had the two brackets side by side you would not notice mine was bent... So that was another issue solved.


So far, leaky hose was fixed on pump, and this fuel pressure regulator bracket lol. Oh lord.


My xj had the original owner 1995-2015 (older lady who drive it to Publix and home for 240,000 ish miles) , than a kid who shouldnt touch cars had it 2015-2016, than late 2016 to now ive had it... Its in good shape besides stuff the kid touched lol. The original owner never even used the 4wd, had to rebuild the t-caze but otherwise was a good xj

Sent from my Moto G (5S) Plus using Tapatalk
 
Back
Top