ZachsXJ

So I'm seriously looking into the prospect of swapping in a 97-up Fuel tank and pump into my 91 XJ.

Reason why:
I've had lots of fuel pump gremlins, and dont exactly like have a steel tank. That along with wanting to relocate my fuel tank to sit with the top inside the cargo area leaves me wanting one of the newer style poly tanks.

The technical mumbo jumbo:
I know that the newer tanks run a higher fuel pressure so I'd have to at the very least swap injectors.

My questions are to have the new pump and tank operate as though they were factory what all would be required? I'm not sure what would be needed to get the sending unit to work with my gauges, and whether I'd need to swap my fuel rail and or my fuel pressure regulator. All that wonderful stuff is what I'm trying to figure out before I buy any parts.
It may be more hassle than its worth but I'm still looking into it just to see what would be involved beyond my knowledge.

As always with me, this question is geared towards the most experienced people here on CF(cough, cough, FrankZ, BlueXJ, KTMracer419 and the like)

and thanks a bunch for all your help/criticism.

ZachsXJ

really. Nobody has any input or advice whatsoever on this? Why do I always ask the unanswerable questions?

Anyways, I'm getting a tank, fuel pump, injectors, an intake manifold AND a Chryco 8.25 off of a 99 XJ for super super cheap($75) so once I get my DD back on the road I'm gonna go ahead and attempt a swap and see how it goes. Should be fun.

Weou09

I dont like how the 97+(whenever the swap was) doesn't have an inline filter...something to consider when swapping.

ZachsXJ

I'd just plumb in my 6 month old filter after the pump.

alpine.adrenaline

I think you're right; as long as you use the same pump, fuel rail, and comparable injectors, they should pulse on time with your ECU. I'm a little wary of the different injectors having too much or too little resistance for your computer's chips. I'll try to find the post where I read that.
Another puzzling part of your upgrade may be the sending unit. I know some years of XJ's use a float (or buoyancy in some way) to read the remaining gas in the tank, at least in most I've seen. You could mount the entire original sending unit in the new tank alongside the new fuel pump... which seems rather jury-rigged. If it's a matter of a difference in resistance based on the float level of the sending unit, you may just have to find the right resistor. Pick up a potentiometer (a variable resistor for tweaking) and run it between the sending unit and your gauge. It may take some time to get it spot on. Then again, it may just plug in and work. I haven't seen much expertise on this upgrade, so way to pioneer, man. I'll be interested in how everything turns out.

ZachsXJ

I've actually never even heard of anyone trying or doing what I'm going to attempt. Later this week I'll be picking up all the parts needed to do the swap so we'll see where things sit then. I'll probably go buy one of the little 12v batteries so I can see whats up with the sending unit and such. Its definitely possible, the other big issue is finding injectors that will work with the new fuel pressure. I may have to do some sort of pig-tail and then run with the stock injectors for the newer XJs

Copytech

Wouldn't be easier to use the new tank and and sending unit but install the old style pump? I'm sure it would fit. You wouldn't have to change injectors or anything else.
You are not going to see any performance gains with the new injectors, so why change them in the first place?

ZachsXJ

It will fit but that defeats half the purpose I'm doing this. The newer style pumps are smaller than the old ones, I know because Napa gave me the wrong pump and I had to have them drive over to me and give me the right one.

As far as performance gains, thats BS. I know because when I went from EV1 to EV6 injectors I got a noticeable gain in throttle response, low end torque and 1-2 mpg gain in gas milage. Not a HUGE amount, but enough to be noticeable just from swapping injectors. Upping the fuel pressure from 39 PSI to 49 PSI will should make another small difference. Higher pressure gets better vaporization of the fuel. Better vaporization = more efficient burn = same amount of energy but faster from the same volume. Its the same exact proven concept as going from EV1 to EV6 injectors.

rich

maybe this will help you out some way.

zedpapa

the fuel pump doesn't set fuel pressure, the regulator does. as long as you don't change the regulator, you should be fine. does your 91 have a return line? i'm pretty sure the 97+ did not so keep that in mind. good luck on the swap.

zedpapa

rich

Think of the fuel rail as a tire ,the heavier ply the tire the more load the less ply the lighter load ,39 psi to 49 psi Looks like a heavier load to me. Better than gas spraying all over the engine compartment.

ZachsXJ

I'm getting a 99 Fuel Rail, injectors, 99 Manifold along with the pump and tank. I want to try out the higher pressure to see if it makes a difference in throttle response/power and gas milage.

Yes, my 91 has a return line. I haven't figured out what to do about that. My thoughts are possibly to just cap the return line. Would that be a bad idea is my question.

I'm not understanding what you're trying to say.

rich

FORD E-150 ECONOLINE 1999 4.2l v6
FORD E-250 ECONOLINE 1999 4.2l v6
FORD F-150 (1999 - 2002) 4.2l v6
FORD MUSTANG (2001 - 2004) 3.8l v6
FORD RANGER (2001 - 2004)
FORD RANGER EDGE (2001 - 2004)
FORD TAURUS (2001 - 2005)
FORD WINDSTAR (1999 - 2003) 3.8l v6
MAZDA B3000 (truck) (2001 - 2003)


6 Cylinder Cars that use this part:

1. FORD E-150 ECONOLINE 1999
2. FORD E-250 ECONOLINE 1999
3. FORD F-150 (1999 - 2002)
4. FORD MUSTANG (2001 - 2004)
5. FORD RANGER (2001 - 2004)
6. FORD RANGER EDGE (2001 - 2004)
7. FORD TAURUS (2001 - 2005)
8. FORD WINDSTAR (1999 - 2003)
9. MAZDA B3000 (2001 - 2003)
All are 6 Cylinder Engines


Year Make Model Engine
2000 FORD F-150 PICKUP V6 4.2L 256cid GAS FI N Engine VIN = 2
2001 FORD F-150 PICKUP V6 4.2L 256cid GAS FI N Engine VIN = 2
2002 FORD F-150 PICKUP V6 4.2L 256cid GAS FI N Engine VIN = 2

Year Make Model Engine
2001 FORD MUSTANG V6 3.8L 232cid GAS FI N Engine VIN = 4
2002 FORD MUSTANG V6 3.8L 232cid GAS FI N Engine VIN = 4

Year Make Model Engine
2001 MAZDA B3000 V6 3.0L 2954cc GAS FI N Engine VIN = U
2002 MAZDA B3000 V6 3.0L 2954cc GAS FI N Engine VIN = U

Year Make Model Engine
2000 FORD E-150 ECONOLINE V6 4.2L 256cid GAS FI N Engine VIN = 2
2001 FORD E-150 ECONOLINE V6 4.2L 256cid GAS FI N Engine VIN = 2
2002 FORD E-150 ECONOLINE V6 4.2L 256cid GAS FI N Engine VIN = 2
2000 FORD E-250 ECONOLINE V6 4.2L 256cid GAS FI N Engine VIN = 2
2001 FORD E-250 ECONOLINE V6 4.2L 256cid GAS FI N Engine VIN = 2
2002 FORD E-250 ECONOLINE V6 4.2L 256cid GAS FI N Engine VIN = 2

Year Make Model Engine
1999 FORD WINDSTAR V6 3.8L 232cid GAS FI N Engine VIN = 4
2000 FORD WINDSTAR V6 3.8L 232cid GAS FI N Engine VIN = 4
2001 FORD WINDSTAR V6 3.8L 232cid GAS FI N Engine VIN = 4
2002 FORD WINDSTAR V6 3.8L 232cid GAS FI N Engine VIN = 4

Injectors in case your interested at some point for the upgrade,And yes I would cap the return line and save it for now in case you have to return to the factory setup.

rich

Just that the system your going to had higher pressure than the original setup because the guys post before mine said you shouldnt have to change anything, I just think because what you want to change to a higher pressure for safty you should change it all which I see your going too I just didnt want to see you have an accident.thats all.

Copytech

Correct me if I am wrong but a 97+ Cherokee doesn't get better mileage than a 96-, so I fail to see how you are going to get better performance than you already have.
I understand the injector swap netted you some gains but changing everything out for the higher pressure doesn't seem worth it to me.

Then again I do know people who drop 10k on a new engine just to pick a 1/10sec in the quarter mile.