89 2.5 L comanche fuel pump

[Overlandmark2020]

Does anyone know of a replacement fuel pump I can install on this comanche. The only part I can find is for the pump itself and I need the the pump and the housing for it as mine is rusted beyond repair. I've checked on here for that info and it all seems to be dated around 2010. I was wondering if someone has come up with a fix that I could use thanks.

[eaglescout526]

MTS makes the sending units new. Theres also a mom and pop shop that will take your sending unit and refurbish it.

[Overlandmark2020]

27 minutes ago, eaglescout526 said:

MTS makes the sending units new. Theres also a mom and pop shop that will take your sending unit and refurbish it.

Thanks for that info. I just looked at MTS and they do have that part. Ive put a new engine and all new parts that go with it, tried to start it this morning and it would not start. I dropped the fuel tank and everyting in there was eaten up with rust. I ordered a new fuel tank and straps from Amazon but could not find the pump. You made a bad day a little better thanks again.

 

[eaglescout526]

No problem. Now I know you said the tank has seen better days but just to be on the safe side, I would do a little electrical diag and make sure all the wiring and what not is in fine shape. Will the engine fire if you poor fuel down the TB?

[JYau]

So I called MTS today and the 2.5 Fuel pump assembly is no longer in production. Now I haven't taken out my fuel pump assembly but it's pretty rusted onto the tank. Does anyone know what my options are? MTS told me that they think the 4.0 and 2.5 assemblies were the same and the pumps were different but they weren't 100% on the assemblies.  

[eaglescout526]

14 minutes ago, JYau said:

So I called MTS today and the 2.5 Fuel pump assembly is no longer in production. Now I haven't taken out my fuel pump assembly but it's pretty rusted onto the tank. Does anyone know what my options are? MTS told me that they think the 4.0 and 2.5 assemblies were the same and the pumps were different but they weren't 100% on the assemblies.  

87-90 used the same units for either engine except for the 16 gallon tank which has a smaller float arm. Just make sure you get the right capacity and you’ll be good to go. Fuel pump doesn’t matter either as the regulator at the TBI will handle the pressure. 
 

Now the only model year that’s special is 86. But literally the only difference is the input and output tubes on the unit at straight outward like the XJ. 

[amsuco]

There's a company that rebuilds the sending unit, if you need that, but it isn't cheap or quick.  I'll let others speak to the pump.  I have nothing to offer on availability of those for your application. 

[Gojira94]

If you go for a rebuild of the sending unit, these guys. They did a clock restoration for my project:

 

Instrument Services, Inc.

4075 Steele Drive

Machesney Park, IL 61115

(800) 558-2674

https://www.clocksandgauges.com

sales@clocksandgauges.com

M-F 8AM 4:30PM Central

 

Speedos

Tachs

Gauges

Clusters

Sending units

[amsuco]

Instrument Services rebuilt my OEM sending unit over this past winter.  It looks good for sure, but I haven't installed it yet to try it out.  It set me back $405. and took around 3-4 months (if I recall correctly).

 

At the time I sent my original sending unit in to be rebuilt, MTS had their new units on backorder, and they'd been on backorder for quite a few months!  Now it's spring and I have both sending units, the original and an MTS.

[MagicJames]

On my 2.5, I replaced the pump and the wiring from a YJ. Everything was plugged exactly the same. But would anyone know if you can buy the orange box I'm pointing at that indicates the fuel level separately? The tiny wires inside are snapped. If anyone knows a replacement, please let me know. Ty

[JYau]

On 4/14/2026 at 4:55 PM, eaglescout526 said:

87-90 used the same units for either engine except for the 16 gallon tank which has a smaller float arm. Just make sure you get the right capacity and you’ll be good to go. Fuel pump doesn’t matter either as the regulator at the TBI will handle the pressure. 
 

Now the only model year that’s special is 86. But literally the only difference is the input and output tubes on the unit at straight outward like the XJ. 

I'm fairly certain I have the 18 gallon tank as my Comanche is '88 SWB 2WD. I read in another thread that only the 16 gallon was used in '86-'87 instead of the 18 gallon tank. And both the 16 gallon and 23 gallon had three tank straps. My tank only has 2 tank straps. Is this correct? I'm going to take my fuel pump assembly out this weekend, if I don't ruin it removing it, I'll probably just replace the pump, otherwise it's a new 4.0 pump assembly. 

[eaglescout526]

1 hour ago, JYau said:

I'm fairly certain I have the 18 gallon tank as my Comanche is '88 SWB 2WD. I read in another thread that only the 16 gallon was used in '86-'87 instead of the 18 gallon tank. And both the 16 gallon and 23 gallon had three tank straps. My tank only has 2 tank straps. Is this correct? I'm going to take my fuel pump assembly out this weekend, if I don't ruin it removing it, I'll probably just replace the pump, otherwise it's a new 4.0 pump assembly. 

I wonder what thread that was in? 
 

So the 16 and the 23 are the same exact tank dimensions. Just the baffle inside stops the fuel filling sooner on the 16 than the 23. 
 

The 23 gallon and 18 gallon fuel tanks share the same sending unit. 
 

16 gallon was available from 86-92 on the LWB. Again, same exact tank dimensions. 
 

18 gallons are for SWB MJs only. 
 

LWB tanks(23 & 16) have three straps that hold the tank up. SWB tank(18) only has the two straps that hold it up. 
 

Now here’s a fun one, 86 TBI sending units are unique to 86 only and the only thing that makes the unique is how the input and output hoses point straight out vs angled towards the engine on the other units.