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Fuel cell question

9

'96XJcrawler

NAXJA Forum User
Location
South Carolina
Im putting a fuel cell in my 96 and because of the fuel pressure regulator being located in the tank as opposed to the fuel rail, i had to get a fuel filter with a built in regulator. I have a summit fuel pump rated to 85 psi but i believe the pump regulator is only rated to 59 psi will this cause the engine to run rich? what might be some possible other options if so?
 
59psi is going to be a little high. Spec for the 96+ is 49.5psi +or- ~5psi.
I'm running a Mallory 4060FI pump and a Mallory 4305M regulator, set at 50psi according to the gauge I put on the fuel rail. It works great.

I will say that while setting it up and until I got the regulator set prefect the engine will run with less pressure at idle, but then stumble at any sort of speed. Higher pressure and everything seems to run alright, but I'm not sure the injectors will like it over a longer period of time. I never ran it with higher pressure for more than a few seconds at idle.
49-50psi seems to be the sweet spot for 96+ engines.
 
Just get a high quality adjustable pressure regulator. It doesn't matter where you put it. The only thing to worry about is to make sure every component between the fuel pump and the regulator will handle the full rated pressure the pump will put out.
I've never looked into the reasoning/engineering, but my off the cuff guess is: When they went from the early(renix and OBD-I) system to the late(OBD-II) the fuel pressure went up, which requires a higher rated pump. They then moved the pressure regulator to the fuel tank so the fuel line from the tank to the engine wasn't under the full unregulated pressure from the pump.
 
ok i see, but with that high of a pressure from my external electric pump, do you think it would blow by the regulator in the filter? Im runnin kind of low on cash and am looking for the cheapest options (I know but im in college, what can i say) any suggestion or pointer is helpful...ive only been in the jeep building game for 3 years or so, so i got a lot to learn
 
'no reason to think you'd get excessive pressure past a regulator unless it failed. What kind/brand filter are you using?

I've never seen a pressure regulator built into a filter, as the filter is (usually) disposable. Can you post a pic?
 
It would be much more helpful to know what kind of pump, filters, regulator, fittings, line, etc you have o want to run. As tbburg mentioned get a high quality regulator (like the 4305M) and make sure you have a gauge in the system (preferably as close to or on the rail) so you can see what really is going on. Obviously depending on the pump the regulator may or may not need to be a return style. Again, we can be of much more help if you provide some more information.
 
the filter is from an 03 grand cherokee with 3 points- 1 for intake-1 for return-and1 towards fuel rail, its at autozone part number ff832 ( sorry i dont know how to post pics)



N-8gd7g
 
This is what I got searching Napa's web site. This it?
Link
705165.jpg
571174.jpg


This might be a pain in the butt to use. It has the snap fittings for all 3 connections, and you'd have to convert your fuel line to the factory style ends to use it, not to mention adding a return line to the system.

I can see what you're trying to avoid. A quick search turned up adj. regulators in the 100-150 range. Not sure if a cheaper solution is available. Are you sure there's a pressure regulator in that GC filter? It looks like a standard filter with a return line. My CJ uses something similar, the return is just to circulate fuel to avoid vapor lock, and there's no regulator function.
 
i might not be opposed to getting one around $100 but where should i mount it and how would i run the lines? Also, which regulator might be a good candidate? (sorry so many questions)
 
'96XJcrawler said:
i might not be opposed to getting one around $100 but where should i mount it and how would i run the lines? Also, which regulator might be a good candidate? (sorry so many questions)
Click to expand...
:rolleyes: OK, one last time.
What is the rest of the system like? What parts do you have (ie, model numbers for pumps, fittings, filters, etc)? What line/fittings do you want to run (AN fittings, barbs, factory "quick" connects)? What cell are you running? Where did you mount it?
We need some more details. It is impossible to give you suggestions on where to mount it and where to run the lines if we don't know where you are starting from. Also it would be nice to know what fittings you are working with or you'll end up with a bunch of odd adapters trying to get a regulator to work with your setup.

There are several good regulators out there (Mallory, Aeromotive, Magnafuel, etc.). We just need to know more about your setup or we'll just end up recommend something that won't work with your setup.

Edit: To give you an idea, here's how I did mine:
Out of 70-micron Walbro pickups/filters from the cell --> Earl's Shut-Off Valve --> 4060FI pump --> 4305M return reg --> EITHER back through another Shut-Off Valve and into the tank OR onto a 10-micron filter --> pressure gauge then finally into the fuel rail.
FuelSystemComplete.jpg
 
Last edited:
the fuel tank is from summit part number
SUM-290111 mounted behind the second row of seats above original fuel tank. the fuel pump is from summit part number SUM-G3138, good for about 85 psi ( 5/16 at both ends) I have 2 -8AN male fittings, and 2 -8AN female fittings to accompany them (with barbed hose ends) I have a -6AN fitting and 90 degree -6AN female end that i was going to use for the return line, i havnt gotten the hoses yet cause that was gonna be the last things i got. for attachment i was just going to get the proper sized fuel lines and just use hose clamps to hold them on the barbs. I know the fittings were awkward and i would have to buy some adaptors to make them work but now im reconsidering buying a regulator and just returning the filter to autozone. If i use the mallory regulator i was thinking i could use summit part number PFS-10231threads to attach the hoses on both sides
 
Last edited:
Do you have filters planned out for your system?
If you use the 4305M regulator you'll need something for -8 AN inlet and return as well. Or an adapter to step down to the fittings you already have.

Three other options:
- The Aeromotive A1000 regulator (#13109). While it might be a little more expensive it does have -6AN for every port cutting down on adapters. $5-10/each on adapters adds up quick.
- The Professional Products 10670 regulator. The cheapest out of the bunch, all the same fittings and should do the job. I don't have any first hand experience with this brand.
- Swap the fuel rail for an earlier model one with a return.

I'm sure there are other regulators out there for cheaper than what is listed above. I just haven't looked for them. I picked up mine to match my pump.
 
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i was just going to use a stock filter since its the same 5/16 as my pump. Ill probably go with the cheapest regulator and just buy some adaptors as necessary. Thanks for all the help and any other pics or suggestions would be great. ill keep ya posted on how its going
 
RCman said:
- The Professional Products 10670 regulator. The cheapest out of the bunch, all the same fittings and should do the job. I don't have any first hand experience with this brand.
.
Click to expand...

I was not impressed with the professional products fuel pump I used in my fuel cell swap. It was terribly noisy from day one, and died after about 25 hours of run time. Dead, dead, like the brushes or bearings were trashed.

I replaced it with an aeromotive pump and all has been well since.
 
'96XJcrawler said:
quick question can the regulator be mounted before the pump cause that would save me some money from buying fittings?
Click to expand...

no, the regulator regulates the pressure coming from the pump to the fuel rail. It MUST be after the fuel pump and before the fuel rail.

Is there a local hot rod shop or some such that can help you with this? It sounds as though you might be out of your depth, and learning on the job is fine, but fuel systems are not something to do willy nilly, you're dealing with high pressure flammable substances here.

Anyway your fuel system should be in the order that RCMan already posted.

fuel cell pickup-filter-pump-filter-regulator-gauge-fuel rail.
 
just know that fuel systems need to be 100%, or bad things happen.

If you have any doubts that what you're doing may not be the right thing then stop and find someone that can help you plumb it. There's some good guys in the southeast chapter that would probably come and help you out if you posted up in the chapter forum.
 
87manche said:
I was not impressed with the professional products fuel pump I used in my fuel cell swap. It was terribly noisy from day one, and died after about 25 hours of run time. Dead, dead, like the brushes or bearings were trashed.

I replaced it with an aeromotive pump and all has been well since.
Click to expand...
Interesting, thanks for the insight. Like I mentioned I've never used any of there products, I guess they are cheap for a reason.
87manche said:
no, the regulator regulates the pressure coming from the pump to the fuel rail. It MUST be after the fuel pump and before the fuel rail.
Click to expand...
Not that it helps in our applications, but the regulator can be after the fuel rail in certain situations.
87manche said:
Is there a local hot rod shop or some such that can help you with this? It sounds as though you might be out of your depth, and learning on the job is fine, but fuel systems are not something to do willy nilly, you're dealing with high pressure flammable substances here.
Click to expand...
Exactly. Make sure you do some reading, make some phone calls, or post up here if you have any questions.
 
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