Fuel pump questions: mods to use with diesel

[Coachgeo]

1. this is a diesel TJ retrofit
2. actual builder skipped the pump. and put crappy fabri-crafted fuel pick up in the tank using a bung. I got to fix it. leaks air into the system.

so here I am trying to do something better than the crappy leaky fuel pickup the original builder created

found out what fittings are needed to mount AN6 line to the TJ's in tank fuel pump as a possible solution... Will help ONLY IF:
A. a 2002 fuel pump either allows for free flow thru the pump when pump is OFF, or when off all something to pulll fuel thru it. (Jeep pump will push too much GPM and pressure with pump on. ) Engine has its own mechanical pump built in. and would rather stick with that option. less electrically limited.
B. if one could gut the pump and regulator above it and just use it as a pick up only

THOSE ARE THE PRIMARY QUESTION

Ifff "A" would work.. then

A {1.0} can one wire the pump to its own relay and switch? Why?? great way to prime the system when needed.. or to pump out the tank to clean her of algae, water etc. Hate their is no drain on tanks these days.
A {2.0} what color wires at tank would one use to do so??...... knowing that will also help me test to see if the pump still in tank, actually works or not.

 

[Gilaguy23]

Ive pondered this myself just because really. Granted Ive never yanked the pump from one of my TJ's but have on the ZJ. Couple things come to mind. Cold potentially gelled diesel in winter getting past the OEM screen/ filter, and the need to have a check valve of some sort to prevent the lift/injector pump from struggling to get fuel back into it. I cant see why the discharge off the OEM pump unit couldn't be modded to be the pickup for the diesel. Its just a crappy little flex line off the pump top.

 

[Coachgeo]

Ive pondered this myself just because really. Granted Ive never yanked the pump from one of my TJ's but have on the ZJ. Couple things come to mind. Cold potentially gelled diesel in winter getting past the OEM screen/ filter, and the need to have a check valve of some sort to prevent the lift/injector pump from struggling to get fuel back into it. I cant see why the discharge off the OEM pump unit couldn't be modded to be the pickup for the diesel. Its just a crappy little flex line off the pump top.

thanks. Pulling the pump here in a hour or so .... having not yet laid eyes on the pump.... when I do... maybe then what you describe about discharge line will make sense to me.

check valve? are you referring to a check valve one would mod into the pump.. or just in a fuel line somewhere in a strategic spot.

 

[Coachgeo]

just putting this here for others.

 

[Coachgeo]

report I am getting by user here @RustyAutoholicGuy what worked well in his diesel conversion
. 2005-6 fuel tank (larger diameter hole and diffrent size pump clamp ring and threads than other years)
. CRD liberty diesel fuel pump unit. (has fuel feed and return line)

at this point in my venture I can't afford the cost and time to go that route (dont have that tank) so will do something similar to the one bleepnJeep did in video above

 

[Coachgeo]

A. Got my pump out now.. gotta figure out *how to get it apart to remove pump and convert it to a fuel pick up (3/8" ID :AN 6) and fuel return (with 90 degree) 1/4" ID :AN 4) per concepts in the BLeepn Jeep video

B. have the Original builders fuel pick up out now. (homemade bulk head fitting). The fitting worked-ish.. kept out water- it appears, did not leak fuel- it appears.. but leaked air.. a fault in parts used to make the fitting. The end was just not really something you can effectively hose clamp onto
I may use this to pump out the tank when needed... still though swap it to a better fitting with a 90 elbow at the top and not the non barbed taper one OP created (pictured earlier). Will use it only as a way to pump the tank out when needed. His feed hose rests on the bottom of tank (where the nasty's sink too... which is another reason why I dont like as driving fuel pick up.

C. will replace both anti roll evaporator bleeds and Tee them. This will be plumbed to be a single tank vent. One is presently the diesel fuel return via a epoxied nipple on it... but IMHO it is too small. its like a 1/8" ID nipple. Bleed in "A" will replace it at 1/4" ID. Will run the vent up to same place I put rear axle vent. "may" remove the vent off the fill tube. Appears it is not anti roll over spill but not sure on that. Interestingly the fuel filler in the tank has an anti rolll over spill built in,

 

[Coachgeo]

anyone know specs / conceptual design of fuel pressure regulator?

I can blow and suck thru this one. (but it could be bad) and there is no electrical connections, so it would appear to me that the regulator is fully mechanical.... sooooo what is it regulating?? preventing over-pressure? Under-presser? ... tries to maintain a constant-pressure??

Reason I ask is.. if the regulator would do nothing in the event of very about low pressure... then I can use the regular to attach my fuel pick up hose to and not fabricate a peace to take place of it.... like in the bleepin Jeep vid. (Diesel pump on the engine is not High pressure GPH.. For example external inline electric pumps for these engines really should not go beyond 9psi. )

Is there a bladder inside??? could see just poking holes in the bladder for more free flow thru it if so??

 

[Coachgeo]

A. Got my pump out now.. gotta figure out *how to get it apart to remove pump and convert it to a fuel pick up (3/8" ID :AN 6) and fuel return (with 90 degree) 1/4" ID :AN 4) per concepts in the BLeepn Jeep video

....

its apart.. the HOW TO really helped. Added a hint in the How to ... that helped me out.

 

[Coachgeo]

anyone know specs / conceptual design of fuel pressure regulator?

I can blow and suck thru this one. (but it could be bad) and there is no electrical connections, so it would appear to me that the regulator is fully mechanical.... sooooo what is it regulating?? preventing over-pressure? Under-presser? ... tries to maintain a constant-pressure??

Reason I ask is.. if the regulator would do nothing in the event of very about low pressure... then I can use the regular to attach my fuel pick up hose to and not fabricate a peace to take place of it.... like in the bleepin Jeep vid. (Diesel pump on the engine is not High pressure GPH.. For example external inline electric pumps for these engines really should not go beyond 9psi. )

Is there a bladder inside??? could see just poking holes in the bladder for more free flow thru it if so??

well according to this document.... the regulator ONLY regulates max pressure. Makes me think the low pressure of my system wont affect it at all

https://www.jegs.com/tech-articles/...MI76398-akhwMVbwStBh3CIgxqEAAYAyAAEgImqvD_BwE

 

[Coachgeo]

Having removed my pump now, and dissembled it. At least on a TJ 97 to 04?.. It sits inside an aluminum canister so doing the add a hose like in Bleepn Jeep video posted earlier.. (his first iteration in video).... it cant barely curl up like he shows his did in video. One could easily secure it in there even more solid inside the canister if one wanted.

I am going that route. Since need a filter in tank... will put an inline plastic fuel filter in there. Thought is to melt some holes into it its plastic body so it free flows better... Will cut /mount hose filter combo just right so nipple sits in the hole in the bottom of the fuel pump canister. Thinking this should keep the hose from curling. Ill have to check to see if the bottom of the canister sits flush on the bottom of the tank or an inch above orrr?? will see and modify accordinlgy

In Bleepn Jeep video he also mentions the Fuel Pressure Regulator (FPR) would need a modification if you were to go with his first iteration..... hmmm. not seeing why!!! According to JEGS write up posted just above this.. on how FPR works they all only regulate a MAX pressure. Our diesels dont go above that pressure. Well least not the OM617. Not sure about the TDI...

That said.. if one's FPR is or goes bad.... one might get fuel flow back into the tank since the FPR also acts a little like a check valve. aka you loose some prime. Plan ahead for putting a check valve inline in easy to reach place for disassembly to clean it out once a year or so.

 

[Coachgeo]

... am going that route. Since need a filter in tank... will put an inline plastic fuel filter in there. Thought is to melt some holes into it its plastic body so it free flows better... Will cut /mount hose filter combo just right so nipple sits in the hole in the bottom of the fuel pump canister. Thinking this should keep the hose from curling. Ill have to check to see if the bottom of the canister sits flush on the bottom of the tank or an inch above orrr?? will see and modify accordinlgy
.....

someone smack me up aside the head. melting holes in the inline fuel filter is DUMB. Wish this site allowed you to self montitor your stuff and delete post.

 

[Coachgeo]

where I am at... ditched the idea of using the FPR. Right now plan is 1 1/2 inch long brass 1/2 NPT nipple. Cut off/out the OEM plastic tube under the FPR and with some shaving via barrel sand paper wheel in a Dremmel ; the nipple now fits into the hole the FPR sat. Leaves EXACT enough thread to cinch it down lightly (sealed to keep out moisture with silicon of some type). cinch it down with fittings.
- Top fitting a 90 elbow. Becomes fuel outlet to engine.
- Bottom fitting a threaded female coupler.
- addition 1/2 male to 1/2 barb at bottom
- Viton fuel line 1/2
- round 4"? fuel strainer with fitting for OD of 1/2 fuel line from Oreily's. (maybe drill some holes in base of the aluminum canister to get fuel coming in better?
- strategically placed zip ties around hose and out to the sides of the canister thru holes drilled in sides. Zips Ties helping keep the fuel line centered in the housing and keep it from curling as others have reported as an issue..... yet allowing it to flex some if bottom of tank gets whacked off road and the whole thing needs to flex up some instead of breaking things (how the OEM is conceptually designed it appears.. aka- why it is spring loaded)

Will do video / pics at final assembly

 

[Rickyd]

I wouldn't want to use a gas tj pump or any of its internal parts. I'd be worried about the rubber parts being compatible with diesel fuel.

Can you gut the fuel module and then drill/tap feed and return ports into it's top?

 

[Coachgeo]

I wouldn't want to use a gas tj pump or any of its internal parts. I'd be worried about the rubber parts being compatible with diesel fuel.

Can you gut the fuel module and then drill/tap feed and return ports into it's top?

agree... not using the pump ... just the housing.. also the pump is too high pressure for a diesel. As to parts degridation. I think Petrol is harder on things than diesel, but I may be wrong.