1988 Comanche fuel pump/ sending unit

[Andrew miller]

Help needed! 

I have a 1988 Comanche (MJ) base model and I am trying to replace the fuel pump/ sending unit, problem is I can not find one to save my life. Can anyone send me in the right direction? Thanks in advance 

[JMO413]

 

The fuel sender is a little off but it works.

[fiatslug87]

What size gas tank do you have? I have one from a RENIX 23 gallon, pm if interested.

[Pete M]

3 hours ago, Andrew miller said:

Help needed! 

I have a 1988 Comanche (MJ) base model and I am trying to replace the fuel pump/ sending unit, problem is I can not find one to save my life. Can anyone send me in the right direction? Thanks in advance 

 

after 9 more posts the classifieds will open up to you.  

[Andrew miller]

I ended up calling MTS company and they had exactly what I was looking for! Thank you JM0413 for the info.... I’ve been looking for weeks and have had no luck. What a relief I can finally get back to the trails!!! 

[BeatCJ]

How is the Fuel Pump working? I am pretty sure that I need one, trying to find the best available.

[JMO413]

Mine is working good except the fuel gauge is inaccurate. 

[derf]

44 minutes ago, JMO413 said:

Mine is working good except the fuel gauge is inaccurate. 

 

I don't know that I've ever had an accurate fuel gauge on any single vehicle I've ever owned.

 

[AZJeff]

4 hours ago, derf said:

 

I don't know that I've ever had an accurate fuel gauge on any single vehicle I've ever owned.

 

Older vehicles have notoriously inaccurate and inconsistent fuel gauges.  I have seen cars that read “1/8” and were fully empty.  I have also owned cars that had 4 gallons left from a 20 gallon tank when it reached “E”

 

However, the one in my Wife’s KJ is pretty good, and the one in my JK is almost exact.  I think that have improved calibration procedures in the past 20 years.

[JMO413]

Mine currently will take 12 gallons when it's in empty. I have an 18 gallon tank so it's pretty far off. I would buy it again for sure though.

[jeeptec1]

I had my sending unit rebuilt by tristar radiator in New York. It takes about a month to get rebuilt.


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[BeatCJ]

22 hours ago, AZJeff said:

Older vehicles have notoriously inaccurate and inconsistent fuel gauges.  I have seen cars that read “1/8” and were fully empty.  I have also owned cars that had 4 gallons left from a 20 gallon tank when it reached “E”

 

However, the one in my Wife’s KJ is pretty good, and the one in my JK is almost exact.  I think that have improved calibration procedures in the past 20 years.

I think its not so much calibration as completely different technology. I don't believe they use a mechanical wiper on a fixed resistance wire any more.

[AZJeff]

Perhaps.  The one in my wife’s 2004 KJ is still a wiper across a thick film resistor trace, so that’s “old school”

 

I will investigate what sort of sender my 2014JK uses....

[AZJeff]

I found out my 2014JK has a fuel guage sender that is virtually identical to the one in my wife's KJ, and very similar to the one in the Dakota fuel pump/sender assembly I use in my MJ.

 

I wonder if the real reason they work better now is that the consistency of the production of the senders and guages is better now due to automated calibration methods.   I know when I worked in the electronics industry, we had shifted from manually "trimming" resistor networks that were embedded on ceramic substrates to using lasers to do so, as they were FAR more precise that someone with the industrial equivalent of a Dremel tool and a diamond cutter.

[derf]

My 2019 Subaru reads empty when it still has a few gallons left in the tank.  I think a lot of manufacturers do that on purpose so that you don't run the car out of gas.  They pop up all kinds of warnings on the screen about low fuel to scare you into filling up.  Which, given that the fuel in the tank keeps the pump cool, it's not a bad idea to follow that advice.

 

But I don't know how linear the gauge reading is.  i.e. is going from 3/4 tank to 1/2 tank the same as going from 1/2 to 1/4 tank?