Keyav8r

If you have $700 and a place to park it, grab it. If I learned to weld you can.

About adding resistors to get additional readings - while testing my fuel sender I opened the circuit to get the empty reading and grounded the lead to the gauge to get the full reading. As an experiment I picked up a fuel pump connector at P&P and wired the ends together (with the exception of the lead to the gauge) so that I could splice it into the circuit. Then I bought some resistors (10 ohm and 100 ohm) that I could jumper into the circuit to add resistance and drive the gauge to read other fuel levels. I had an approximate 30 ohm resistance from the sender which gave a gauge reading of about 5/8 full. Adding one 10 ohm resistor gave an approximate 40 ohm resistance. Adding two in series gave an approximate 50 ohms. Putting two 100 ohm resistors in parallel in the circuit gave an approximate 80 ohm reading. Et cetera, et cetera. The ohms are approximate as the resistor values approximate (10 ohm resistor metered at around 9.6 ohms, 100 ohm metered at around 96-97 ohms). Adding the resistance in the circuit drove the gauge to corresponding fuel level readings back toward empty, confirming my assumption that the gauge was good throughout the empty to full range. That could have been assumed from the empty and full readings, but I just wanted to do the experiment. Sent from my iPad using Tapatalk

Adding these to my "to Do" list. Comparing the list additions to the completions, I should have everything currently on the list done by around 2035. Cruiser - !

"Any person with a small amount of sense....". Not many of them around these days! People walk and drive directly behind my truck all the time with my backup lights on. They seem to think they're invulnerable. Or, they're just too dumb to know better.

Thanks, Cruiser!

dinghyboy - IIRC, the center (purple or blue) is the gauge wire. The black is the ground and the brown or orange is the 12V. I would go look at mine to confirm but it's at the office because I plan to use the shop blast cabinet to clean it prior to coating. I believe you're right on the testing by disconnecting and grounding. You can probably do the grounding by jumpering across the center pin (or socket) and the ground pin (or socket) on the body half of the connector. You can also add resistors in the circuit (if you can find them, Radio Shack is almost extinct in our area) to get intermediate readings.

Hippie66 - I dropped the tank because I wanted to get a good look inside and also wasn't sure how much fuel was in it. Turned out it was a lot more than I thought. And, the sock came off the pump when I pulled the assembly. Could have dropped the driveshaft, but decided to drop the tank instead. Also gave me a chance to recheck the vents. When I put them in they were a little loose but they've tightened up pretty well. I guess the gas fumes swelled the rubber grommets a little. Zambeezy - The fuel gauge would not go to full with a full tank. Sitting still and engine running it would show 1/2 to 5/8 tank then drop to around 1/4 tank when I started moving. Never went close to empty, but the low fuel light would come on sometimes. i just fueled up at 150 to 200 miles.

My 91 (HO) MJ fuel gauge has not worked correctly since I have owned it. I had previously tried to check the ohm output by reaching in through the filler neck with a bent coat hanger (the universal tool) and moving the float arm through the range. I got low and high level readings that seemed to be good and some intermediate readings that looked close. I had previously checked out the gauge and wiring from the tank to the gauge by unplugging and grounding the connector and by rigging a connector that would allow me to add resistance in steps to check the full range of the gauge. Gauge and wiring checked out okay. Next step - I dropped the tank and removed the fuel pump/sending unit assembly. Here it is on the workbench. With full access to the sending unit I found that the ohm output was very spotty because the pivot point on the sending unit was loose due to wear and allowed the float arm to "flop" around, which caused the movable contact (part of the float arm attachment) to move away from the stationary part. This is the point where pure dumb luck comes into play. While looking for a fuel pump connector to rig to test the gauge and wiring, I crawled under a 91 XJ at a P&P and found the fuel pump/sending unit laying on the ground, less the fuel pump. I took the sending unit off the bracket with the thought I might be able to "rig" it to repair mine. This is my MJ sending unit on the left and the 91 XJ unit on the right. The obvious physical differences are the longer float arm and the longer blue wire on the MJ unit. The black wire is the ground to the bracket and is the same on both. I hooked each one to my multimeter and checked out the high and low readings. MJ unit high reading. MJ reading low reading (had to hold the arm in place to get an ohm reading). XJ unit reading high reading. XJ reading low reading. The XJ sending unit ohm range is pretty close to the MJ range and the polarity is the same, so it should work in my MJ. Next, to address the float arm length and the blue wire length. First, I carefully pried the float arms out of the MJ unit and the XJ unit and swapped them. That last photo is the XJ sending unit with the MJ float arm snapped into place. Be careful in removing and replacing the float arm in the sending units - 25 year old plastic pieces. Next I used a soldering iron to remove the blue wires from both units and put the longer wire on the XJ unit that now has the MJ float arm. Last step - held the sending unit vertical and moved the arm throughout its range to assure I still had good ohm readings at all points. I checked the ohms with both digital and analog meters (per Don's recommendation). In the next few days I'll sandblast and paint the bracket with Klass Kote epoxy (thanks to Akula's post for the coating info) As soon as my new fuel pump arrives from Amazon (thanks again, John), I'll reassemble the pump and sending unit onto the bracket, install it in the tank, and re-install the tank. Hopefully, this will give me a working fuel gauge. I'll post a final report as soon as that is done. Sent from my iPad using Tapatalk

Doesn't register the actual fuel level. The movable "pickup" part of the rheostat doesn't maintain contact with the stationary part due to looseness in pivot. Float arm flops around. More detail later in a write up.

Coming in the full write-up on sending unit repair.

Found Akula69's post on re-building sendind units. He used Klass Kote two-part epoxy primer on the units he rebuilt. E-mailed the local distributor to see if he stocks it. Write-up on repairing a sending unit in the works (if I can get a handle on posting photos).

Sent from my iPad using Tapatalk

Sent from my iPad using Tapatalk

Adam - Glad you're okay and sorry about the XJ. I feel your pain (as Slick Willy used to say) about uninsured drivers. I had a guy rear-end me who had an expired drivers license, no insurance and was driving a friend's car that was uninsured. The officer who investigated the accident wrote the other guy a ticket but refused to follow-up with the vehicle owner who was a block away. End result, my truck was repaired by my insurance. The insurance companies claim they don't count points against you if you're hit by an uninsured motorist, but my agent tells they actually do consider every dollar that's been paid out when renewal time comes around. So, those of us who pay for insurance end up paying for those who don't. Maybe the clown who hit you will develop a conscience and pay up. And, maybe pigs will fly. Call me a cynic.

As a follow-on to my fuel pump question, I need a recommendation on a paint or coating for my fuel pump/sending unit bracket. It looks a little rusty and I want to blast it and put a good rust preventative coating on it for protection. What has been used with good results?

Thanks for the tip, johnj. Just ordered the warehouse deal pump. Should have it by next weekend, but I doubt I'll have my sending unit sorted out by then. Just one more project in the apparently never-ending story of a Comanche owners life.

Looking for recommendations on the best fuel pump to buy. Rock Auto has several offerings and I'm leaning towards a Carter kit that includes a Bosch pump, new strainer, etc. Pulled it out to check the sending unit (bad!) - will try to do a write-up on the planned cure.

National news tonight had a warning about a new phone scam. Your phone rings with a number you don't recognize (even if your phone is on the Do Not Call registry). The caller says "This is John Doe with the customer service department (or something like that). Can you hear me clearly?". If you respond "Yes", they record your voice, then use it as proof that you approved a charge, service, or contract. If you get one of these calls, hang up without saying anything.

My wife had both knees replaced at the same time and they had her up on her feet the day after surgery. She's a hell of a lot tougher than I can even think of being. If you have it done, the trick is to work hard on your therapy. Find a therapist who will push you past your comfort level. There is pain associated with the surgery and discomfort with the therapy, but she tells me it is much better than the constant pain before the surgery. She says "total" recovery takes about a year to get to the point where you don't really think about your knees during the day.

Don - Sending you a PM.

Yeah, we probably won't be doing much skiing since the forecast for the end of the week is 70F. This Snowpocalypse really didn't live up to its publicity.

Local channel weather coverage is showing a lot of the slipping, sliding, stalling in the middle of the interstate. Sections of I-20 East towards Atlanta are parking lots, mostly 18 wheelers that made it that far and stopped. Atlanta's airport, one of the busiest airports in the US (if not the busiest), is being reported as having hundreds of flight cancellations, really impacting travel to Tampa for the National Championship game. Since this storm continued across GA, it's probably hampering travel for Clemson fans. Should be better tomorrow as the sun is starting to do a pretty good job on the streets around here. If all these jokers who just "have to be somewhere" would wait a couple more hours they could get where they're going much easier. Leaving now they may wind up sitting on a blocked highway for a long time, or possibly wrecked in a ditch or against a median barrier. Despite all the miracles of modern medicine, you can't fix stupid and stubborn.

Snow kinda fizzled around our house. Not really enough to cover the grass well. But the weather guessers were pretty close for some areas a little south and west of us. Looks like downtown Birmingham got 1-1/2" to 2" in places but not enough to close the airport. Temperature is down around 24 F with a 14F wind chill and dropping, so we'll have plenty of icy roads tonight and tomorrow. And, as Pete said, it's the ice that causes most of the problems down here. Most folks down here don't realize how little traction you have on ice without chains or studded tires and they try to drive like they always do. Lots of bent sheet metal as a result. I'll be in the garage working on the MJ until the thaw comes. Got gin and tonic and enough food to last a while, so won't be doing any traction testing. I'm in no hurry to get anywhere. If I were to rate 2014 as a 10, this one would be a 5, maybe a 4. Haven't heard of any people stranded yet and no major pile-ups. Icy roads tomorrow may change the score but maybe not.

Try Rock Auto for the AC hoses. I bought some hoses, receiver/dryer, condenser, expansion valve and other AC items from them last month for my '91. There is a hose that goes from the expansion valve (at the evaporator) to the compressor that they stock. Then there is a hose from the compressor to the condenser (also available), a hose from the condenser to the receiver/dryer (couldn't find that one anywhere), and a hose from the receiver/dryer to the expansion valve (at the evaporator, also available). If you need a compressor, Rock Auto has a package with the compressor, a receiver/dryer, an expansion valve and an o-ring set. The evaporator that they, and everyone else, sells does not look like the stock evaporator and doesn't have provision for the thermostatic probe that is part of the control circuit. The other items I haven't located are the compressor suction and discharge service valves. They do not come with a replacement compressor. Hopefully mine, and yours, won't leak. If you have trouble finding part numbers on Rock Auto's website drop me a PM and I'll look for them on my receipts. Good luck on those rear inner fender flares. They're like honest lawyers - almost impossible to find.

Sitting on the couch watching the arrival of our first (hopefully only) 2017 Alabama snow/sleet/ice event. Looks like the front edge coming from Mississippi just hit the Birmingham area - freezing rain, etc - but the roads haven't been impacted yet. The ground is still fairly warm as we've had 50-60 F days for the last few weeks. I'm hoping this will turn out to be much ado about nothing, but I'm not betting that it's not going to get messy. Fortunately, I'm off today so didn't have to make the "should I go to the office and gamble on getting stranded there" decision. Yeah, I know that you Northern and Canadian guys are saying unkind things about Southerners getting all worked up over maybe 2"-3" of snow. Guys, we aren't prepared for this stuff like you are. Limited salting and de-icing equipment and no plows because we get snow so rarely and it stays on the ground for a short time. But, a decent snow (2" or more) shuts everything down. All the school systems cancelled Friday classes yesterday afternoon. And, of course, we've had the run on the grocery stores - milk, bread and beer stocks severely depleted! Everyone down here remembers the "Snowpocalypse of 2014" that shut down Birmingham, Atlanta and other AL and GA cities, and stranded thousands at work or on the highways. Go ahead and call us wimps, but we don't want to do that again! Dang global warming is the culprit! Update - one of my wife's Facebook friends just posted that her car was completely iced over driving home from work. Looks like Snowpocalypse may be on!