Your Tech Questions Answered
Endless Air Wiring for Dummies
So I’m workin’ on the endless air project for my ’91 XJ. I’ve pretty much got all I need for the conversion. Wiring is not my thing. My XJ never had A/C to begin with. I’m an idiot when it comes to wiring. I wired in my electric fan. I thought I was cool, sat there turnin’ it on-n-off, feelin’ cool. That is, until the wires started to burn through my firewall. You’ve never seen someone recklessly tearing out wires, screamin’ “No, no, not my Jeep!” So as stated, I need to know exactly how to go about the wiring of this A/C to on board air. Where and how do I wire the 12-volt switch and to what? My XJ has a lead for where the A/C would go do you use it as well? Bypass it? i don’t know! Please Jp, help me. You’re my only hope.
Wow man, I’d say anyone could wire this, but now you’ve got me scared. Course we all had to start somewhere and I too was once a wiring dummy. I know the feeling of dread when smoke pours out from under the dash of a beloved vehicle and you are not sure why. Aaah! Looking back at the article the wiring looks pretty straightforward to me but I’ll try to explain it another way. Basically you need to start with a wire coming from your XJ that is hot (has 12 volts) when the ignition switch is in the on position and dead when the ignition switch is off. You can probably splice into the wire feeding the cigarette lighter for example. You will probably need to disassemble part of your dash to get to the wires. There may be other fused terminals on the Jeeps interior fuse block. The cigarette lighter wire is fused in your XJs fuse box and so if something goes wrong with the wiring it should just pop the fuse rather than set your Jeep on fire. You must not have had a fuse wired in correctly with your fan switch example above. The wire you splice into the cigarette lighter wire will then be connected to one terminal on an on-off switch that goes somewhere on your dash so you can turn the system on or off as you need. Then a wire from the other terminal from the above mentioned switch will have to be run from under your dash, through a rubber grommet in your firewall to one terminal on the pressure switch. Then another wire will have to be run from the other terminal on the pressure switch to one of the wires coming off the A/C compressor. The other wire coming from the A/C compressor will have to be grounded to the chassis or body of the Cherokee. Hope that makes sense. This way in order for power to travel to the A/C compressor clutch, and the compressor to do its thing the car must be keyed on, the on-off switch has to be on, and the pressure on the system has to be below 110 psi. Also make sure to use 14-12-gauge multi-strand wire. Not household solid copper or aluminum wire. Make sure the insulation does not get damaged when passing through the firewall of the Jeep (try to go through an existing grommet). If the copper wire gets exposed anywhere in the system (except the ground wires) and touches the body or other metal part of your Jeep it will short out and pop the fuse.
How Much Is Too Much?
I have an ’06 TJ Sport with the Dana 30 front and Dana 44 rear with no locker or limited slip. I have a 4-inch suspension lift 1-inch body lift. I previously was running 32-inch tires from back when I had a 2-inch budget lift (which is what I’ve run for the last 4 years). Now, within the next year or so I’m going to upgrade to 33-spline Alloy USA axles with an OX in the rear, and then at some point after that I’m probably going to end up swapping in a Dana 44 front with similar axle/locker combo.
About a month ago I cut a tire and it was not repairable. The 32-inch tires I was running were BFG MTs (the old style). Since you can’t really get them anymore, I decided to get a new set of tires. After a bit of research I saw Discount Tire had the KM2s in 35x12.50R15 for basically just a few bucks more per tire than the 33-inch size. The people I normally wheel with have been suggesting I run 35s, since I put the 4-inch suspension and 1-inch body lift on last fall. So anyway, I ended up upgrading to the 35-inch KM2s.
When I had the 32-inch tires, I have wheeled the snot out of my TJ up at Rausch Creek and a couple of other places. I haven’t yet had time to get out and test the KM2s, but I’m kinda concerned about how my stock axles will hold up in the meantime. So, my question is, considering that I’m open/open, and I do have the Dana 44 rear, should I be OK to continue wheeling like normal, or are my axles ticking time bombs waiting to explode?
Depending on how hard you are on your Jeep you should be fine with 35s and an open Dana 30 and Dana 44 combination. Now having said that it is possible to break stuff even on a stock Jeep if you really beat on it and having open differentials might cause you to use more throttle on certain obstacles than if you had lockers and lower axle gears (assuming you have stock gearing in your axles). Also, you don’t tell us if you are running an auto or manual. Generally, autos are easier on drivetrain parts. I’d keep my eyes on the front axle U-joints and avoid really rough high-speed off-road driving since Dana 30 tubes are known to bend. If you get into a situation where you have lots of traction and loads are high you can break an axleshaft, U-joint, or a spider gear even without lockers. It’s a good idea to be prepared to fix stuff if you break it. It’s part of the deal if you wheel hard.
Endless Air Issues
In the last month of Jp there was an article called “Endless Air” (July ’12). In this article it says to disassemble the compressor to clean and lube the bearings. There is also a warning piston must line up with thrash plate. As far as I can tell I have done this with two compressors, and I have managed to bend the pistons on reassembly. What is the secret to getting this thing back together? Can you back off the plug in the bottom of the body? If so, how do you know or where can you find the specs on what the torque is so as to not bend stuff? I am at a loss. No one I have talked to has taken one of these things apart. They forgo that and pump it full of grease or do an inline oiler and a separator. I was going in the greased direction as in the article. Some help please?
Author Trent McGee replies:
Sorry to hear you are having problems. Here’s what I did: Once all of the little pistons are seated in their holes, make sure the connecting rods are vertically aligned with their respective piston and not cocked or angled to one side or the other. Install the front housing of the compressor and start all of the bolts. As you gradually snug the bolts up (use a star pattern to tighten the bolts), rotate the center portion of the compressor clutch to actuate the internals as the bolts tighten up. If all of a sudden you can’t rotate the compressor by hand, stop! Back off the bolts and start over. I’m not an expert, but I think rotating the compressor as the front housing bolts are tightened helps keep the thrash plate properly centered. The other thing to consider is that if you pump the compressor full of grease without cleaning out the compressor oil, there’s no way the grease will get everywhere it’s supposed to, and it’s my understanding that the PAG or ester oil is not compatible with grease…whether it breaks down grease or simply repels it, I dunno. I’m not a chemist. But they don’t play well together, and taking it apart to clean everything out helps ensure there’s plenty of grease where there’s supposed to be, plus you get a pretty good idea what kind of shape the compressor is in.