Fuel Tank, Pump, and Plumbing Differences: early models vs. 05-06

Slim

Slim

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Genright's got a deal going on their 15 gal tank. For reasons, I want the tank, but they've only got the 05-06 model in stock.

Can I use the 05-06 tank in my '97?

From what I can find in some quick googling, it looks like the only differences are the fact it's got a machined pump ring (which should still accept the '97 pump), and I'll have to do some relatively minor vent plumbing.

Can anyone confirm that those are the only differences?
 
I think the pumps have a slightly different diameter where the tank seals IIRC.
 
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Slim said:
Genright's got a deal going on their 15 gal tank. For reasons, I want the tank, but they've only got the 05-06 model in stock.

Can I use the 05-06 tank in my '97?

From what I can find in some quick googling, it looks like the only differences are the fact it's got a machined pump ring (which should still accept the '97 pump), and I'll have to do some relatively minor vent plumbing.

Can anyone confirm that those are the only differences?
Click to expand...

It should be the main differences. The pump ring is easy, either use the later pump or modify the flange diameter slightly to fit the ring. I'll have to double check but I've used the "wrong" pump with the screw on lock ring and then the clamp style mounting rings just by changing the flange size slightly. I can tell you that the later pump will accept the early fuel connector.

Corrected below after I measured.
 
Last edited:
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mrblaine said:
It should be the main differences. The pump ring is easy, either use the later pump or modify the flange diameter slightly to fit the ring. I'll have to double check but I've used the "wrong" pump with the screw on lock ring and then the clamp style mounting rings just by changing the flange size slightly. I can tell you that the later pump will accept the early fuel connector.
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Later pump runs higher PSI, doesn't it? Non-issue for the 4.0? (assuming the regulator is good)
 
The PCM will compensate for higher fuel pressure to a point, but it is best practice to run the pressure the engine was tuned for. Going from the earlier pump to the later is over a 20% increase in pressure.
 
Jezza said:
I think the pumps have a slightly different diameter where the tank seals IIRC.
Click to expand...

Correct, I just measured them. The 05-06 has a flange diameter of 5.95" and the earlier 97-02 have a flange diameter of 5.75". What would need to be checked is whether or not the smaller flange can land on a sealing surface on the 05 tank ring. Worst case is just run the 05 pump which I believe has a reversed + and - so the pump would run backwards.
 
Jezza said:
The PCM will compensate for higher fuel pressure to a point, but it is best practice to run the pressure the engine was tuned for. Going from the earlier pump to the later is over a 20% increase in pressure.
Click to expand...

Inline pressure regulator should fix it, no? Any idea what the JK pump runs?
 
mrblaine said:
Inline pressure regulator should fix it, no? Any idea what the JK pump runs?
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An inline regulator would lower it back down. You may have to cut a return port into the tank with a bulkhead fitting for the regulator. No idea on the JK, I had to look up the TJ as I couldn't remember exactly. FSM says 49.2psi for the early and 58psi for the later pump. That's actually only 17% not over 20% as I stated earlier.
 
mrblaine said:
The reason I asked is I am running an OEM JK pump on a TJ 4.0 with no issues so far.
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Great knowledge. Thanks. I think it's worth pulling the trigger on this thing and running the new pump. From looking at it, I'll just have to splice two different size vent hoses to fit, but that should be it.

499 for a new tank+skid with the added compatibility/ease with imminent stretch project makes a lot of sense.
 
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Slim said:
Great knowledge. Thanks. I think it's worth pulling the trigger on this thing and running the new pump. From looking at it, I'll just have to splice two different size vent hoses to fit, but that should be it.

499 for a new tank+skid with the added compatibility/ease with imminent stretch project makes a lot of sense.
Click to expand...

Make the line splices look as factory as possible so you don’t have to deal with the CARB nazi’s.
 
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Slim said:
Great knowledge. Thanks. I think it's worth pulling the trigger on this thing and running the new pump. From looking at it, I'll just have to splice two different size vent hoses to fit, but that should be it.

499 for a new tank+skid with the added compatibility/ease with imminent stretch project makes a lot of sense.
Click to expand...

Don't overlook I said "so far". It has been in use for about a year. That isn't long term enough to fully know.
 
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mrblaine said:
Don't overlook I said "so far". It has been in use for about a year. That isn't long term enough to fully know.
Click to expand...

Noted, thanks.

Unfortunately, looks like they bumped the price up while I was fucking around, so it's not quite worth it. Oh well, helps the next guy that has the question.

Thanks, all.
 
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