cruiser54

Gotta do ALL of them. No shortcuts. Here. I'll lay them all out for you. Did you even click on my link? There's photos there. Renix Ground Refreshing The Renix era XJs and MJs were built with an under-engineered grounding system for the engine/transmission electronics. One problem in particular involves the multiple ground connection at the engine dipstick tube stud. A poor ground here can cause a multitude of driveabililty issues, wasted time, failed emission tests, and wasted money replacing components unnecessarily. The components grounding at the dipstick tube stud are: Distributor Sync Sensor, TCU main ground, TCU "Shift Point Logic", Ignition control Module, Injectors, ECU main ground which other engine sensors ground through, Oxygen sensor, Knock Sensor, Cruise Control, and Transmission Sync signal. All extremely important stuff. The factory was aware of the issues with this ground point and addressed it by suggesting the following: Remove the nut holding the wire terminals to the stud. Verify that the stud is indeed tightened securely into the block. Scrape any and all paint from the stud’s mounting surface where the wires will attach. Must be clean, shiny and free of any oil, grease, or paint. Inspect the wire terminals. Check to see that none of the terminals are crimped over wire insulation instead of bare wire. Be sure the crimps are tight. It wouldn’t hurt to re-crimp them just as a matter of course. Sand and polish the wire terminals until clean and shiny on both sides. Reinstall all the wires to the stud and tighten the nut down securely. While you’re in that general area, locate the battery negative cable which is fastened to the engine block just forward of the dipstick stud. Remove the bolt, scrape the block to bare metal, clean and polish the cable terminal, and reattach securely. Another area where the grounding system on Renix era Jeeps was lacking is the engine to chassis ground. There is a braided cable from the back of the cylinder head that also attaches to the driver’s side of the firewall. This cable is undersized for it’s intended use and subject to corrosion and poor connections at each end. First off, remove the cable end from the firewall using a 15mm wrench or socket. Scrape the paint off down to bare metal and clean the wire terminal. Reattach securely. Remove the other end of the cable from the rear of the head using a 3’4" socket. Clean all the oil, paint and crud from the stud. Clean the wire terminal of the cable and reattach securely. A suggestion regarding the braided cable: I prefer to add a #4 Gauge cable from the firewall to a bolt on the rear of the intake manifold, either to a heat shield bolt or fuel rail bolt. A cable about 18" long with a 3/8" lug on each end works great and you can get one at any parts store already made up. Napa has them as part number 781116. A further improvement to the grounding system can be made using a #4 cable, about 10" long with 3/8" terminals at each end. Attach one end of this cable to the negative battery bolt and the other end under the closest 10mm headed bolt on the radiator support just forward of the battery. Napa part number 781115. For those of us with Comanches, it’s very important to remove the driver’s side taillamp assembly to access the ground for the fuel pump. Remove the screw holding the black ground wire. Scrape the paint from the body and corrosion from the wire terminal. Reattach securely. If you want to upgrade your grounds and battery cables in general, contact Jon at www.kelleyswip.com. He makes an incredible cable upgrade for a very reasonable price. 　 Revised 03-04-2013 I suggest unplugging EVERY electrical connection in the engine bay you can find, whether engine related or not, and spraying it out with a good electronics cleaner, visually inspecting the terminals making sure they haven’t retracted into the plastic holder, and then plugging it back together. There’s a critical 10-pin connector for the front lighting system located in front of the air cleaner and behind the left headlight assembly. Don’t miss that one . Also be sure that the connectors to the ballast resistor mounted near the air cleaner housing are clean and tight. ALL of the relays should be removed, the terminals wire-brushed until shiny, and the receptacles sprayed out with contact cleaner. Then plug them back in. I do this on every Renix Jeep I purchase or work on for someone else. Revised 07/23/2012 Renix Jeep C101 Connector Refreshing 　 The C101 connector on 1987 and 1988 Renix Jeeps was a source of electrical resistance when the vehicles were new. So much so that the factory eliminated this connector in the 1989 and 1990 models. The factory recommended cleaning this connector to insure the proper voltage and ground signals between the ECU and the fuel injection sensors. We can only imagine how this connector has become a larger source of voltage loss and increased resistance over a period of almost 25 years. The C101 connector needs to be cleaned at least once in the lifetime of your vehicle. Chances are it’s never been done before. Almost every critical signal between the engine sensors, injectors, ECU, and some to the TCU, travel this path through the C101 connector. The C101 connector is located on the driver’s side firewall above and behind the brake booster. It is held together with a single bolt in it’s center. To get the connectors apart, simply remove the ¼" bolt and pull the halves apart. You will find the connector is packed with a black tar like substance which has hardened over time. Take a pocket screwdriver or the like and scrape out all the tar crap you can. Follow up by spraying out both connector halves with brake cleaner and then swabbing out the remainder of the tar. Repeat this procedure until the tar is totally removed. This may require 3 or more repetitions. Wipe out the connectors after spraying with a soft cloth. If you have a small pick or dental tool, tweak the female connectors on the one side so they grab the pins on the opposite side a bit tighter before bolting both halves back together. 　 Revised 03-02-2013

Wanna bet? According to my Renix MJ diagram, the reverse light circuit is fed by a 7.5 amp TRANS fuse.

In case someone with a 91 (or possibly 92) has a similar backup light problem, this only applies to a Renix systems. There is no under dash Trans fuse for the HOs. The POWER/COMFORT switch is fed by an independent 10A fuse up in the PDC. Pulling this fuse defaults the AW4 to the POWER mode. Good to know.

True on the switch light. I eliminated the switches on all of mine and just jumpered the harness. Put one of those blanks in the dash.

Factory color on the comanche was Hunter Green.

It's history.

You may never find out why so you've gotta take some steps. I would do the complete ground refreshing, connector refreshing, and test the CPS. stick or auto trans?

The first time I saw that posted years ago, I immediately went out to the garage and pulled the Trans fuse to see if it could be true. LOL.

Bingo!!!

Jeep went out of their way to make sure the 4wd models could be easily towed behind RVs. It was a great selling point. Having been a Service Manager and Shop Foreman at a Jeep dealer for 12 years, and then owning my own towing company for 13 years, I can assure you that Jeep's system, as designed, works perfectly. No need for doing anything more.

So how did the 91 through 93s with a 231 get flat towed behind RVs then? No CAD. and supposedly the change in the 231 wasn't til 94? And, doesn't the CAD rely on the vacuum storage football in the front bumper? Even if the engine isn't running, there would be enough residual vacuum to engage the CAD......

90 is exactly the same as 87. There is no lock between driveshaft except with the lever in one of the 4wd modes. I don't feel like typing out the whole procedure from the owner's manual, but it is not necessary to keep the engine OFF.

I'll tell ya why I know it will be fine. Years ago, when I had one of my 13 Comanche demos from the dealership, I took my family and visiting cousin out on an excursion. About 3 people were riding in the bed. I found that when at slow speeds, I could hit the washers and spray the folks in the bed and make them scream.

A bad fan clutch could very well be your issue. Not the auziliary fan.

4wd yes. 2wd no.

When you're at speed, where does the fluid hit? Think about that.

Unplug the speed sensor off the transfer case. Clean out any crap in the connector. Do the same with the trans connectors in the engine bay. click on the link in my signature and there some instructions with photo on the plugs in the engine bay.

The reason I mention a stick is that the CPS attracts the metal shavings from clutch material to it. That reduces their output signal. Autos don't have that issue. That's why cleaning it fixed your problem, for now. Renix CPS Testing and Adjusting Renix CPSs have to put out a strong enough signal to the ECU so that it will provide spark. Most tests for the CPS suggest checking it for an ohms value. This is unreliable and can cause some wasted time and aggravation in your diagnosis of a no-start issue as the CPS will test good when in fact it is bad. The problem with the ohms test is you can have the correct amount of resistance through the CPS but it isn’t generating enough voltage to trigger the ECU to provide spark. Unplug the harness connector from the CPS. Using your voltmeter set on AC volts and probing both wires in the connector going to the CPS, crank the engine over. It won’t start with the CPS disconnected. You should get a reading of .5 AC volts. If you are down in the .35 AC volts range or lower on your meter reading, you can have intermittent crank/no-start conditions from your Renix Jeep. Some NEW CPSs (from the big box parts stores) have registered only .2 AC volts while reading the proper resistance!! That’s a definite no-start condition. Best to buy your CPS from Napa or the dealer. Sometimes on a manual transmission equipped Renix Jeep there is an accumulation of debris on the tip of the CPS. It’s worn off clutch material and since the CPS is a magnet, the metal sticks to the tip of the CPS causing a reduced voltage signal. You MAY get by with cleaning the tip of the CPS off. A little trick for increasing the output of your CPS is to drill out the upper mounting hole to 3/8” from the stock 5/16”, or slot it so the CPS bracket rests on the bell housing when pushed down. Then, when mounting it, hold the CPS down as close to the flywheel as you can while tightening the bolts. Revised 01-26-2013

And after all that, relocate the vacuum ball to the underside of your coolant bottle bracket, eliminating all those problematic vacuum lines running to the bumper and back.

Bought yourself some time. Is it a stick shift by chance? Will it rev over 3000 now?

Happens all the time. Back to basics, eh?

Good. Now do the ground refreshing anyway and save yourself some future headaches.

Now that sounds like a trans issue.

I just use Permates #1 or 2, or teflon paste thread sealant.

Trans won't cause a locker to do anything. Maybe there's a problem with the locker?