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How did you upgrade your fuel pump to run the stock ls how did you upgrade the gauge with a t5 transmission the driveshaft can I reuse it or is there another one that will work it a t5 transmission rwd with a ford 8.8 short bed?

Hey ya'll! My wonderful MJ died on the road last September and sat at home unloved for the winter, so it's time to get it running again. This is what I've done/discovered so far. I replaced the fuel pump since it no longer primed when I turned on the ignition and assumed that was the problem. Fuel gauge has never worked and it turns out the floater on the old pump had broken off, so I hope the new one will let me know how much gas I have. I refreshed the ground behind the tail light following cruiser's instructions, and will eventually relocate the ground to the fuel filter, but the ground is now good. I ordered the big 7 from jeepcables.com and will be doing that this week. I've determined the fuel pump relay is good and cleaned the connections. I've gone through the grounds and discovered the the braided line from the engine the chassis is gone! Could this be a possible fix? The fuel pump is definitely good when I use a probe and give it direct power. Basically I'm at a bit of a loss as where to look next. The engine cranks just fine but the fuel pump is not getting any power even to prime it when I turn on the Ignition. Maybe a fuseable link? I'm going to put in a proper fuse/relay box from a 90's cherokee in there eventually, but I just want the thing running again so I can at least move it/work on it in the garage when the weather is bad. Any help is appreciated :) If you need more info ask away and I'll do my best to answer Goddamm Renix jeeps man...

So I got my new sending unit from MTS Company today. Got my old pump out in a hurry. Then the comparisons started. It is a almost perfect. The only sight difference is the length of the fuel gauge sender arm. It does read resistance correct for a Renix. It fit awesome. The fuel gauge is only slightly lower that my OEM sender. The pump is super quiet. An awesome small company in Iowa! How would of thought they would make a complete sending unit? JPSU-6P is the part number. That is complete with fuel pump. Leave the P off for just the sender. $160.45 shipped with tax. Just the sender is $89.99 Sender with pump, sock, seal, & lock ring. The lock ring didn't fit on my Spectra tank. I reused the old one. I'm guessing it would fit on a stock tank. Empty resistance reading .9 OHM's on a scale of 200 Full resistance 88.5 OHM's New and old. My pressure line tube is almost ready to fall off. Connector end. I like how they ran the ground through the connector. It's not on the outside of the sender. This is awesome for us rust belt guys.

In my 88 pioneer, i6 4.0L that I’ve recently purchased I’ve changed out the fuel filter and fuel pump/assembly after it sat for a year-ish. It ran decent with the old gas that was in it but since I’ve added new fuel in it runs like crap. I’ve added seafoam and got the oil changed. When it runs anywhere above 3,000 rpm and then I let off the gas it drops below 750rpm, stutters and almost/sometimes dies. I’m not sure what to check next since I’ve done the fuel pump and filter. Thanks in advance!

Would appreciate any help that can be given, I've been pulling my hair out on this. I have never been good with electrical stuff, and I recently purchased a '89 Comanche with the fuel tank out of it. I hooked up the fuel tank and tried to start the truck, but the fuel pump will not prime or pump when cranking. I've cleaned all grounds, swapped my relays around, bypassed the ballast resistor by setting a paperclip between the connectors, and still have nothing. The pump works when setting the battery up directly to the pump. I set a paperclip between the 30 & 87 on the fuel pump relay, and still nothing. I checked the ground behind the tail lamp, and even cleaned it up, but still have nothing. I tested the rear lights and they work so I don't think the harness back there is part of the problem. I attempted to test voltage at the connector right before it plugs into the pump, and got 12v during the prime. I'm not sure I tested it right, so any guidance is helpful. I am getting 12v at the starter relay fuel pump ballast terminal connection. I looked at the fusible link on the starter relay fuel pump ballast terminal & it appeared to be fine, I was also getting 12.4v at the link. I'm sure I might be leaving some things out, so please ask any questions and I'm happy to answer. I'm really at a loss of what to do at this point. Any advice or guidance?

Can anyone help with this wiring issue. Got the pump working but guage isn't hooked up. Blue goes to the guage but I got 3 extra wires coming from the plug

Alright Jeep guys, have you guys ever bought a Fuel Tank for your Comanche? If so, have you ever replaced the fuel pump? I have a 1990 Jeep Comanche with 4.0 I’m replacing the fuel tank and fuel pump but cannot find the correct fuel pump. Ordered from rock auto and advanced auto but I keep getting a Cherokee fuel pump any ideas?

This is my first post although I've been wrenching on this beast for years. To be more exact, the last time I messed with it was over 15 years ago. I'm the original owner. Now my son just turned 17 and it's time to hand it down. I looking to restore her to her former self or better. It's going to be a long road. This unit has seen a lot of living. The dealer blew up the engine at 38K miles (that's an entirely different story). Started as a daily driver, used it as an old school SCORE chase vehicle for Mike Q, Benny Cannala, and the Lewellin brothers (for those of you who are old enough), and then a bit of street fun that lead to an engine fire. Used to have a Sneeky Pete throttlebody NOS system. I didn't know that it would weaken the injectors / seals. It resulted in a weenie roast under the hood. To this day I can't figure why AMC put the fuel injectors right over the exhaust manifold. I had to replace all of the electrical, vaccum, plastic, fuel rail, etc. Never repainted the hood, so I just spray painted an eightball over the burnt spot. I started to call it the "Oddball" and the name stuck. I'm hoping that I can pick up some wisdom on this site.

I just recently bought an 88 Comanche that is a really big Frankenstein with a 91 Cherokee. I went to fill up the tank and as usual in jeeps, the pump wanted to stop every 5 seconds. Tried going slowly but nothing worked. It took me 10 minutes to get 2 dollars in, and when I did the gas started to overflow. That is where my bigger issue is... there is barely any gas in the tank and it won’t fill up? Any help? THANKS!

Fuel pump wiring was messed up by previous owner so I hot wired from 87 on the fuel pump relay and the pump works great but only starts for about 3 seconds. Did I skip over something and the ECM is freaking out? 1988 4.0

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So I need some help. I'm helping my Grandson build his first MJ. We found a almost perfect 2WD minor rust ran great some standard issues like Steering column falling apart. We found a MJ 4x4 donor and did a 2wd to 4x4 swap and fixed the steering column. Now we have no power to the Fuel Pump. I know the Pump is good cause I can hot wire it. Ran a continuity check all the way back to the resistor block and the wiring is fine. also checked the relay and it seems fine. When we turn the key everything works but the fuel pump, If I hot wire the pump the truck runs. I can't figure out what we would have done that is not telling the relay to send power to the pump. I know and checked the connector and switch block on top of the steering column I haven't removed it yet cause everything works but the pump when we turn on the key. any ideas? Thanks in advance.

I have a 1989 comanche eliminator. Inline 6, 4x4, AX15, 3 inch lift. Been driving fine. Just bought it a couple weeks ago. Has a bit of high idle. Leaks here and there. Smallest amount of coolant in oil but it does have 268k miles. Gonna do the head gasket and such soon. I drove it and parked it, no problem. Blinkers stopped working but was going to look in to that. Been following Cruiser54's tips for sprucing up grounds, adding some, etc. Will keep doing them as i go. The next morning after i parked it in my swamp of a driveway, it wouldnt start. Normally i turn the key and the pump primes, its loud. I can hear it while driving but it seemed fine. Definitely noticeable. This time, no prime. So being before work i didnt do much besides bang on the tank and switch the relays around, nothing. After work, i checked ballist resistor, 1.1 ohms, bypassed anyways to no avail. The relay was swapped around with all the rest so that rules out the relay. I checked for power at pump, i get 6 volts off of the plug for pump with key in on position. I'm thinking that's kinda low. I also get 6 volts if i hook up the wire (bypassed ballist resistor) to my meter and ground it on body. So I'm sure its getting to the pump but maybe not enough? I also did Cruiser54's tip of adding a independent ground on the pumps harness just to be sure as well as clean ground behind taillight housing. I have power on pin 30 of relay and switched ignition power on pin i believe 85 (trying to remember what pins are what). I tried jumping power to the pump and that didn't work. I also removed the pump (before i added the extra ground point to it) and hooked it to the battery for a split second, and it did run. So I'm positive the pump itself is okay. Right now I'm working on tracing wires and connections and sprucing up plugs, etc. I tried looking around other forums, etc for ideas but I'm not sure at this point. Any ideas or thoughts would be greatly appreciated.

I just bought this 89 jeep comanche. Iran fine everything was good that I went to put a little bit of oil in it because the valve covers leaking gasket was leaking and I seen a little bit of milky oil in the rocker arm so I said oh no I've blown head gasket. so I check the oil no water on the dipstick. I'll pull one spark plug at a time to see if water comes out of the block as it turned over and that was a negative.put a new valve cover gasket on it, changed the oil, drove about 6 miles when I had a drop of oil pressure when I pulled up to a red light. I kept it going by having to keep my foot on the gas. It completely died out and the fuel pump quit entirely. Can someone please tell me what's going on?

I've been putting this truck back together now for sometime. The engine electrical in mostly done and connected. I'm missing an O2 and Crank sensor. The O2, has been relocated and I need to extend the harness, and I had the incorrect crank sensor. I pulled the MJ sending unit from the tank. I put the XJ pump and XJ fuel gauge sending unit on the MJ pump mount. I recently finished the main power on the MJ, Battery and feeds. I turned the key, for testing. I hear the fuel pump for about ~2 sec, but get no fuel pressure. Disconnected the hoses and no fuel flow. I've read in passing, that the ECU will shut the fuel pump off if the crank sensor is disconnected. Is that true? I'll have all the sensors connected this weekend, and try again. Just trying to figure out why I have no fuel pressure.

I was wondering which fuel pump, and filter to get for my 1989 Jeep Comanche 4.0l i6. I was looking at some on rock auto but wasn't sure which one would fit and be good to go rather then having to modify any wires. Thanks for the help!

I have a new to me 88 Comanche. Suddenly it quit running. Discovered if I turn off air conditioner, it runs fine. Apparently a short kills fire to the fuel pump as soon as air it turned on. (not the blower) but air. I've had jeep shop search for cause without success. Has anyone experienced a similar problem? Thanks.

Hey guys, I'm about to place an order for some replacement parts,and I'm hoping that you could give me some confirmation on the partnumbers. I've read that Rockauto isn't always correct, so maybe some members with more experience can chime in. I have a 1986 2.5 TBI with an AX5. For the motor mounts, Anchor 2569 and 2571. These seem correct, how do people feel about Anchor? Transmission mount: Anchor 2570: http://www.rockauto.com/catalog/moreinfo.php?pk=315178&cc=1181382. I checked my current transmission mount, and I can see four studs on it, but on some websites I see a mount with only two studs listed for the AX5. Is four studs correct for an AX5? I would assume so, but I've never had to replace it before. Finally, I'm pretty sure I need a new fuel pump. I ran it near dry on accident and it's making a horrible, horrible noise. I'm going to see if maybe the filter is clogged, but if it's not I will need this pump. The pump I chose: http://www.rockauto.com/catalog/moreinfo.php?pk=976874&cc=1181382 with a new bosch trainer, too. Thanks for any comments.

Hey guys!, So I have a slight problem with my truck, the other day i was leaving school and got in my comanche ready to head home when i turned the key and (insert sound of 4.0 liter trying to start but not quite getting there here.) and i said to myself no problem, i have been having some throttle body issues so some starting fluid should do the trick, and just like any owner of a 20+ year old truck should have in their emergency kit, i had some. so i popped the hood and sprayed some in and tried to firer her up again. it still did not start but this time was really close. It had never not started after a little starting fluid so i was a little concerned, but i tried for another 10 minutes at it or so, it still didn't start. At this point having no tools i needed to call in back up, so i called a family member and told him to bring the tools. When he got to the truck we went through all the basic stuff (plugs, electrical lines, throttle body sensors) but came up empty handed, and then my cousin said to me "can you hear the fuel pump come on when you turn the key?" and sure enough when i turned the key i didn't hear anything. So naturally at this point we concluded that it was a fuel pump and i would have to change it in the school parking lot the following week. Later that weekend my dad and i went out to the truck and he told me to try and start it, it started right up and i was able to drive it home. Has this happened to anyone else or am i just the weird one out. In these situations i would have rather it had not started in the parking lot with my dad because at least then you know what you are dealing with. Now there are a lot of unknown variables, and i don't want this to happen again. Thanks, Peter

1989 swb, 4x4, 4.0, 5spd. I am in the middle of dropping in another engine and have 90% of the engine harness ran. As of right now i have two issues, 1. starter clicks only once when i turn the key, I have to wait a min, with key off, before i can get it to do it again, interior lights and radio work normally the whole time. Battery is fully charged, terminals are clean and tight, starter relay is good with all old connectors cut off and replaced with shiny new ones, starter also works fine, installed on engine and tested with jumper cables before dropping engine into bay. 2. Fuel pump no worky, worked perfectly when i took it out, EDIT: also the ballast resistor has been bypassed. I know the problem is the ground, I just don't know where/how the fuel pump is grounded, the plug for the pump (at the back of the cab) is getting power, just no ground I can have pictures up within min if you need to see something. thanks guys, ftpiercecracker