What is it that makes 96 fuel pump unique?

[DirtySouthXJ]

Hi,

Why is the 96 xj 4.0 fuel pump exclusive to the 96 model year? In other words, is the tank mounting point different? Is it a software/pcm issue? Why couldn't another year pump be used? Thank you.

[Saudade]

1996 was a transition year for the XJ. As far as I can tell from the parts guides, '96 tanks still had the fuel pump opening on the side (front of the tank) but moved the fuel pressure regulator to the pump assembly so no return line on the rail.

In '97 forward, the pump opening moved to the top of the tank with a different fuel pump assembly.

My '96 parts guide list the fuel pump assembly as:

PN: 4798941; QTY:1; Model: XJ; Description: 1996, (Comes with Fuel Pressure Regulator).

[Anak]

All of Saudade's info is correct.

You could mount an earlier H.O. pump in a '96, but you would have no fuel pressure regulator.

The '97+ models which have a fuel pressure regulator on the pump module use a completely different tank. You could swap in a late model tank and fuel pump module, but then your fuel gauge would not work properly. What I do not know is if you could swap the little board that is swept by the fuel level arm and thereby get a late model module to propely communicate with an early gauge. That might make a Genright tank workable in a '96.

[gradon]

I upgraded to a walbro 255lph when I had a 96 if that helps.

[DirtySouthXJ]

Excellent information, thank you all!

I will check out the Walbro and see what it is all about.

It sounds like another option would be to swap to a 95 pump and fuel rail?

Being a bastard year, I'm wondering if it would make sense to swap any of the 96 exclusive stuff over to 89 (?) - 95 preemptively to avoid single year set up headaches in the future. I wouldn't mind being able to run a single 02 sensor, delete the airbag and anything else that adds complication and isn't legitimately necessary for the engine to run. I would even consider going carbed if the block had provisions for a mechanical fuel pump.

[Anak]

The big problem between '95 and '96 is the fuel pressure. It is 30psi for the '95, 49 psi for the '96. The computer depends on those numbers for the fuel trim.

You would need to figure out if you could get away with installing an adjustable fuel pressure regulator on the '95 fuel rail. I think the factory design incorporates a vacuum connection on the '95 and down, whereas the '96 has no such input/feedback loop. You would need to figure out how to make the adjustable FPR behave like the '96 FPR.

Or you would need to convert to the '95 computer. Or re-program the '96 computer to run the '95 fuel trim.

The deletion of the airbag would probably be a steering column swap. There is no wiring associated with the '95-'96 airbag. It is entirely mechanical. I think the biggest issue would be your insurance company.

All that said, as an owner of a '96, I have no issues with the single year, bastard status. I would happily buy another '96 if the right one came along. Having OBDII is an advantage in a number of ways. I have yet to come across any issue that makes me regret having a '96.

[RCP Phx]

You sure as hell dont want a carb as that would make for even more problems. The walbro pump is just that, a pump only that you would install on your pump assembly.

[DirtySouthXJ]

Originally Posted by Anak

The big problem between '95 and '96 is the fuel pressure. It is 30psi for the '95, 49 psi for the '96. The computer depends on those numbers for the fuel trim.

You would need to figure out if you could get away with installing an adjustable fuel pressure regulator on the '95 fuel rail. I think the factory design incorporates a vacuum connection on the '95 and down, whereas the '96 has no such input/feedback loop. You would need to figure out how to make the adjustable FPR behave like the '96 FPR.

Or you would need to convert to the '95 computer. Or re-program the '96 computer to run the '95 fuel trim.

The deletion of the airbag would probably be a steering column swap. There is no wiring associated with the '95-'96 airbag. It is entirely mechanical. I think the biggest issue would be your insurance company.

All that said, as an owner of a '96, I have no issues with the single year, bastard status. I would happily buy another '96 if the right one came along. Having OBDII is an advantage in a number of ways. I have yet to come across any issue that makes me regret having a '96.

Thank you, that info is very helpful. FI vehicles (at least ones I care about) are new to me, so I'm trying to understand why a fuel pump would be so specific to a single year out of a 17 +/- year run.

I'd like to install the older (metal) three spoke style steering wheel because I like the look. I'm not too worried about insurance because I know they will never be able to match the value to me personally. In other words this 96 XJ is my baby, I love it; the value to me goes well beyond the blue book or sum of parts "value". Besides that, just being able to find a replacement in similar condition and without needing to purchase remotely and/or possible long distance shipping is very slim imo. They are out there but snipers have been buying these things up, slapping some wax and a roof rack on it and looking to make a $10-15K profit on an XJ with 150K miles on it (cough..cough..davis autosports). I get everybody is trying to make a living, but this practice is dirty in my opinion, it takes reasonably priced vehicles off the market effectively and inflates the "value" of all XJ's out of reach of many who truly love them. Not that XJ's are any less of a vehicle, but they are not as popular, in demand or scarce as something like a 57' Chevy Bel Air coupe or 68' Camaro etc. Beware of anyone who advertises a vehicle, part or anything else as "rare", they are looking to juice you.

That is good to hear, and I love (and I mean reeeaaalllyy love) my 96 so far. "Bastard" may have been too harsh. Again, I love my 96 and plan to keep it and keep it running forever; it will get a full restoration (resto mod) inside and out, top to bottom, down to every single fastener, clip, wire etc. Blasted to bare metal (inside, outside, in pillars and rockers etc.), all metal body work (body solder/lead work, no bondo at all) and preserved with the best paints/coatings availible. The frustrating part is single year specifics; I would hate for a vehicle to be sidelined because a single year exclusive part couldn't be sourced and that is the source of frustration. I've done it before with a vehicle that only had three years to source body/glass parts from and it was very, very frustrating to think that you could end up with a vehicle that could never be truly complete because the parts aren't able to be found and nobody reproduces them.

Thank you again, this information is very helpful.

[Anak]

So to be clear, the part that is specific to the '96 is not the pump itself, but the fuel module (which includes the pump).

This may help: https://www.naxja.org/forum/showthread.php?t=1107991

You can drop in a Walbro or Bosch pump. I was successul in dropping in a Crown FPR. The little board that operates the fuel gauge was once available as a separate unit and may still be found on ebay at times. And I believe someone (Crown?) now offers the complete fuel module (probably not the same quality as OEM, but at least something is out there). In short, there are options.

[Saudade]

Are you actually having an issue with your fuel pump? The pump it self can be replaced as long as the rest of the assembly functions ok.

[Unclewolverine]

Also going carbed would be extremely difficult if you have an auto. The transmission is exclusively electronic control and a stand alone tcu is expensive and complicated.

[En2 4355]

Rockauto has the full USMotorworks '96 assy for $120.

96' 280k & was going strong on OE gear, but tweakers pushed the maint forward for me

install a new one, replace the consumables in the old one & set it aside for a rainy day.....

I figure i'm good for a while, for under $200 and my labor.

I also replaced the fuel filter, blew the lines and ran the grey injectors in the small HarbFrt ultrasonic cleaner w/ Dawn.



smooth as silk now, so much so - I decided not to drop the cheddar on 4 hole injectors.

[DirtySouthXJ]

Originally Posted by Anak

So to be clear, the part that is specific to the '96 is not the pump itself, but the fuel module (which includes the pump).

This may help: https://www.naxja.org/forum/showthread.php?t=1107991

You can drop in a Walbro or Bosch pump. I was successul in dropping in a Crown FPR. The little board that operates the fuel gauge was once available as a separate unit and may still be found on ebay at times. And I believe someone (Crown?) now offers the complete fuel module (probably not the same quality as OEM, but at least something is out there). In short, there are options.

Excellent! Thank you! I have not had a chance to read through all of the pages yet but from what I see you did a very thorough job documenting everything and I will be studying the thread I did see a Crown assembly availible and it did appear to be complete, it seemed like reviews were mixed but some of that could be operator error.

Originally Posted by Saudade

Are you actually having an issue with your fuel pump? The pump it self can be replaced as long as the rest of the assembly functions ok.

I am not, and hope I do not lol! I like to try and be ahead of things if possible, especially once a buddy told me that 96 had an exclusive set up different than any other year. I guess it's the whole 2 is 1 and 1 is none mentality. Not sure if it is true but the same guy told me 96 was the year that the most XJ's were made? Very interesting if true.

Originally Posted by Unclewolverine

Also going carbed would be extremely difficult if you have an auto. The transmission is exclusively electronic control and a stand alone tcu is expensive and complicated.

My 96 is an auto, but I do have an AX15 and the supporting parts on standby just incase. I like mechanical, mechanical everything lol. Manual locks, manual windows, manual shifting etc. Power accessories and automatics are great when they work and a nightmare when they don't, at least for this idiot (me). I may put together a carbed/mech pump setup based on the 4.2 and I have entertained the idea of going full mechanical diesel to ditch the entire ignition system and go to a single wire for a glow plug. We will see, I'm not opposed to having multiple options on deck, ready to go.

Originally Posted by En2 4355

Rockauto has the full USMotorworks '96 assy for $120.

96' 280k & was going strong on OE gear, but tweakers pushed the maint forward for me

install a new one, replace the consumables in the old one & set it aside for a rainy day.....

I figure i'm good for a while, for under $200 and my labor.

I also replaced the fuel filter, blew the lines and ran the grey injectors in the small HarbFrt ultrasonic cleaner w/ Dawn.



smooth as silk now, so much so - I decided not to drop the cheddar on 4 hole injectors.

I like the way you think! And yeah, I can't bring myself to scrap parts which could possibly be rebuilt or repaired. Who knows, that part may be what someone else needs one day to get their sidelined vehicle back on the road.

[fenns7]

Originally Posted by Anak

So to be clear, the part that is specific to the '96 is not the pump itself, but the fuel module (which includes the pump).

This may help: https://www.naxja.org/forum/showthread.php?t=1107991

You can drop in a Walbro or Bosch pump. I was successul in dropping in a Crown FPR. The little board that operates the fuel gauge was once available as a separate unit and may still be found on ebay at times. And I believe someone (Crown?) now offers the complete fuel module (probably not the same quality as OEM, but at least something is out there). In short, there are options.

Anak is the oracle on this topic - using his guide I swapped over the fuel guage sending unit from my original (and very tired) '96 fuel module to a new one from Crown. The reason for this ? The Crown module looked to all intents identical to the OE - even had the requisite fuel pressure regulator - BUT the sending unit (the metal 'rainbow') gave completely incorrect readings at the guage. Being a bit OCD this bothered me.


As Anak says the sender unit/board was available but no longer so I just unclipped it from the old module together with the wiring and fitted it to the new module. Job done and has worked perfectly for the last 3 years.


I took video of removal of the unit so I didn't mess things up but cannot load video to this board but (if I remember how to do it) here's a photo of the sender unit:

[fenns7]

I did email Crown (and their European distributor) to alert them to the problem sending unit but highly doubt they'll have fixed it for a single year - too expensive. Just dont junk the old module before keeping the sending unit