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cherokee fuel pump same as a comanche?


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So the other day i went to pick up a ride on mower it was about an hour there and an hour back, truck ran like a top like comanches do when i got home i unloaded the mower then started the truck to move it and it turned over started and it started shaking and "put, put ,put.." almost like it wasnt getting gas but i had a half a tank in it though. Also the gas gauge was reading backward, like it was past the full when off but when i turned the key ahead it goes back to 1/2. The gauge started reading funnny a few months ago , when it was on a 1/4 of a tank it was almost out of gas even ran out once on us :P. I tired tapping on the tank no go. Let it sit for an hour or so then tried and it started drove into town almost got to were i was going and "put,Put,put.." i coasted into a parking lot. I replaced the fuel filter but it didnt do much for it i got it towed home. Today i went to the junk yard to get a fuel pump thought that might be it but still not sure. He only had cherokees and told me i could have it for free if i took it off my self :brows: so I'm just wondering if there the same cuz i don't want to take my tank apart and put it back together for nothing. I think the pumps off like a 1992 or so also if there is any other suggestions as to what might be the problem that would be nice to thanks.

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I know for a fact the Renix 4.0l pumps are the same for the Cherokee and the Comanche. I have replaced the pump in my 87 Comanche, I have replaced the pump in my buddy's 90 Cherokee. Original Bosch pump was the same, new replacement Airtex pump was the same with the same part number.

 

The sender/pump assembly is different, but the same pump mounts to both.

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the renix xj pumps i have are different than the mj pump that was in mine. the lower part of the mj pump was larger and made of a ceramic material where the xj pump was a metal tube. other than that they appeared to be the same. so the xj pump should work as long as you use the sock for the xj pump as well

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So the other day i went to pick up a ride on mower it was about an hour there and an hour back, truck ran like a top like comanches do when i got home i unloaded the mower then started the truck to move it and it turned over started and it started shaking and "put, put ,put.." almost like it wasnt getting gas but i had a half a tank in it though. Also the gas gauge was reading backward, like it was past the full when off but when i turned the key ahead it goes back to 1/2. The gauge started reading funnny a few months ago , when it was on a 1/4 of a tank it was almost out of gas even ran out once on us :P. I tired tapping on the tank no go. Let it sit for an hour or so then tried and it started drove into town almost got to were i was going and "put,Put,put.." i coasted into a parking lot. I replaced the fuel filter but it didnt do much for it i got it towed home. Today i went to the junk yard to get a fuel pump thought that might be it but still not sure. He only had cherokees and told me i could have it for free if i took it off my self :brows: so I'm just wondering if there the same cuz i don't want to take my tank apart and put it back together for nothing. I think the pumps off like a 1992 or so also if there is any other suggestions as to what might be the problem that would be nice to thanks.

 

What year and engine is your MJ?

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Don't be confused, the way I read this its about the pump only. Not its cradle/carrier. The cradle/carrier is different as the tanks are different. But everything I have read says like years pumps are the same. I have a 1990 pump in the garage for the MJ when the next one goes. When I swapped out my tank last month I compared the XJ and MJ pumps and to my eye they where identical.

 

I have had very bad luck with aftermarket pumps... :shake:

 

CW

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There were differences in pumps in the early years between engines and models w. different gas tanks. All this was finally cleared up in 91 when the HOs arrived; then all models and tanks used the same pumps. I'm going to do a spreadsheet tomorrow regarding the swapability between 85-92 MJ/XJ senders, pumps, and tanks. And please guys, when aking a question regarding part compatibility, give the model year and engine (and fuel tank if applicable) when you post - it will save everyone guessing and putting out possible bum dope.

 

And 100% agree w. CW regarding aftermarket pumps; they usually don't last long. And yes, I'm sure there are exceptions :D , but I always use the OEM Bosch pumps when replacing. :thumbsup:

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The year and make is a 1988 short box automatic its a six cylinder 4.0. We got the tank off to night and pulled the pump out there was a slight difference in length between the two of them. Also the pumps were quite different the mj one was alot taller then the xj. The sock had a hole in it on the mj one so i don't think that helped it out much. Is there amy way to test the pump while its out of the tank to see if thats truly what it is? thanks for all the help guys. :cheers:

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You didn't really need to drop the tank to get the sender unit out.

 

To test the pump, a bucket of water, run a + and - lead to the pump, but don't stick it in the bucket of water, keep the leads out of the water, and see if it is pumping.

 

With the sock filter having a hole in it, theres a chance it suck up a piece of "junk" from the tank (rust scale) and that's what killing you pump.

 

Every MJ fuel pump I've seen is the Bosch, and most parts store carry this set-up, which is the Bosch replacement.

 

http://info.rockauto.com/Carter/P74155_ANG.jpg

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If you pulled the pump from a 92 that's an HO pump, an entirely different animal than the OEM Renix pump in your 88. I don't think it's going to work for you because of the size problems and the output pressure are different. You guys have NAPA stores in Canada - I'd recommend getting the below new. It has the OEM Bosch pump, strainer, and correct pressure and GPH specs for your rig. Unless you want to take a chance with a used Renix pump from the yard. Not worth it IMHO mate. :cheers:

 

http://www.napaonline.com/masterpages/NOLMaster.aspx?PageId=470&LineCode=NFP&PartNumber=P74155&Description=Fuel+Pump+-+Electric+In-Tank+Type+-+OEM+Equivalent

 

And yes, I've tested them in a bucket filled w. fuel using a 12V battery or charger source. Just be careful and have your switch a good distance away from the bucket. Don't run it dry.........

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You can turn on the fuel pump without the key being switched by putting a jumper wire between connection 5 and 6 on the diagnostic connector #1 on the right side of the fender behind the battery. Its the small connector with a yellow cover on it.

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If you pulled the pump from a 92 that's an HO pump, an entirely different animal than the OEM Renix pump in your 88. I don't think it's going to work for you because of the size problems and the output pressure are different. .

 

Don (and OP), I'm running a full pump/sender from an HO MJ on my Renix.....it works fine, excpet the fuel gauge reads backwards and is several ohms off...1/4 tank on the gauge is "full" (not sure what is empty, never ran it past 7/8 on the gauge ;) )

 

Jeff

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Don (and OP), I'm running a full pump/sender from an HO MJ on my Renix.....it works fine, excpet the fuel gauge reads backwards and is several ohms off...1/4 tank on the gauge is "full" (not sure what is empty, never ran it past 7/8 on the gauge ;) )

Jeff

 

Well Jeff that shows that the pressure and delivery of the HO pump works fine with the Renix engine. :D But the HO pump in the 88 Renix sender still will present problems mate. If it can be done that would be great and eliminate the polarity problem too.

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hornbrod...

 

 

my 91 H.O. fuel pump is the same size as the renix pumps. the sender cradle is almost the same with slight variation because of the different float sensor for the fuel gauge.

 

 

however, I have a spare 91 XJ pump/sending unit that I had gotten after assuming it would be the same. it is not. it's about half the size of the MJ pump.

 

 

looking everything over, neither of them were modified to fit at all. I've verified it as well by looking at other sending units.

 

 

how then, are they the same parts?

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Every 91 and up regulation HO Bosch pump I've seen is of a smaller size than the 90 and below regulation Bosch Renix pumps. However there were aftermarket pumps made for the HOs (Walbro, even some Bosch w. a different part number) that are sized differently than the OEM pumps. They usually make up for the size difference w. rubber collars and other adapters so it fits in the OEM sender.

 

Go to the NAPA site and you can see there are maybe 5 or 6 different pumps available for the 91 4.0L MJ/XJ alone. I've had all these pumps out on their counter and each pump was a slightly different size than the OEM Bosch pump.

 

Bosch supplys many US and foreign car makers their in-tank fuel pumps. If I could only get my hands on a Bosch in-tank fuel pump catalog, I'd be willing to bet there are several submersible models out there that are close enough in size and pressure/output specs that would work just fine in both Renix and HO MJs. Probably a lot cheaper too. :cheers:

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