Fuel pump questions for 97+ engine swap

[Waytard22]

So I'm balls deep into my 97 conversion on my what was a 90 Mj that had a 2.5. Doing the 4.0 engine interior electrical the 9 yards. I know the 97+ fuel tank will not fit which is fine I already put a new Comanche tank in it when I first bought the truck this spring. My question is, with the Comanche ( I know it's just a Cherokee pump since they don't make Comanche pumps from what I've read anymore) but will that pump work for the newer motor I know the lines from the Comanche pump and tank are different than what I need to go into the 97+ fuel rail but I can make new pressure lines from the tank to fuel rail. I just need to know if the pump will be alright.

 

The flow rate as seen below is 10 GPH less than the newer pump but the pressure is much higher.

 

Just curious if anyone had tried the older pump with new system and how it held up. Or if I would be able to put the 97 pump into my 90 tank

 

 

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[Dzimm]

Your best bet if you want to keep the tank is to use a 97+ fuel pump assembly or try to make the pump and sending unit work on the 90 assembly. From my understanding of it the resistance is reversed between how the old sending units and new sending units read. So you can't (it's extremely difficult and idk if it has ever been done) change it so the resistance is correct for the 97+ gauges. What people usually do is adapt the 97+ assembly to the MJ tank, buy/build a fuel cell, or the route I am taking with mine, use a mid 90s Dodge Dakota fuel tank and pump assembly. The Dakota pump assembly uses the same plug and resistance as the 97+ harness and gauges so it is a direct plug and play and is the correct depth for the tank. There is a "guide" floating around somewhere of what years Dakota tank and pump assemblies to use for that. I will try to find it.

 

Edit: I forgot to mention, I have heard that the older comanche and cherokee pump assemblies are actually backwards of each other so don't buy a full assembly expecting it to fit. Just the pump itself may work. Someone will chime in with more experience with the older pumps, mine mostly lies in the 97+. I just don't want you going and buying one just to realize it doesn't work.

[Dzimm]

http://comancheclub.com/topic/30755-dakota-22-gallon-tank-and-fuel-pump/page-2

 

Here's one of the best threads I found for the fuel tank issue if you go the Dakota tank route. Alexias build thread has some good info on this fuel tank/pump situation also.

[Waytard22]

Awesome i knew there was a a post out there I just couldn't remember how I had found it before, probably going to have to go with the Dakota tank then, now that you mention it I remember the resistance being backwards too thanks for the link

 

 

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[Dzimm]

Yeah no problem! And if you do go the Dakota tank route and want the 22 gal, hold out until you find one. I called every junkyard around here (about 20 of them) before I found somewhere that had one. Seems like everyone has the 15 gal.

[MeanLemons]

I also read about using a TJ tank and pump

[Dzimm]

I also read about using a TJ tank and pump

Those fit almost perfectly in the spare tire location IIRC. Some people use that location for a secondary tank. Would be awesome to see a writeup of that process, I've never come across one.

[shelbyluvv]

I have a TJ pump, tank and gauge cluster in my truck. It can be done but is a bit of a pain to do.

[Waytard22]

I have a TJ pump, tank and gauge cluster in my truck. It can be done but is a bit of a pain to do.

Have a build write up on it?

 

 

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[shelbyluvv]

Yep, project onyx

[johnj92131]

Bo, that TJ tank was a replacement for the stock Comanche tank, right?  Not a second tank in place of the spare tire?

[shelbyluvv]

Correct John, it could easily fit in the rear tire area as an auxiliary tank though.

[Dzimm]

Is there any other fuel tank/pump options for the 97+ swap that anyone can think of?  I'm working on a "complete" guide on the 97+ swap for easy reference as I don't think one exists anywhere.  What I know of is the XJ pump adapted MJ tank, fuel cell and xj pump, Dakota tank and pump/sender, and the TJ tank (borrowing some info from project ONYX,  you will be in the credits shelbyluvv).   I've been reading through any and all info on the swap I can and am trying to put all the important info in one place.

[shelbyluvv]

Guide is already done. Check the DIY section

[Dzimm]

I'm guessing your talking about backdraft's writeup? That is a very good one but is still more on the side of build thread to me. He does well explaining what needs to be done but really only explains way he did it, and just mentions the other options. If you go the route he took for his conversion on everything, then that writeup is all you need, but if you want to go different routes you still have to go do some digging. I'm thinking more along the lines of explaining all the "known" or "common" options for doing everything. I would include things like what work needs to be done, what parts are needed, where those parts can be found and for roughly how much. Unless there is something like this that I can't find anywhere, backdraft's is the most detailed one I can find and I feel that it needs more info to include the other options.