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Mine is a 1991 Eliminator, 4wd, 4.0L, auto. Thanks. Add that to your signature. :cheers: I have never seen, or heard of, a procedure like this to erase the 1991 OBDI ECU memory and "learn" new settings so quickly. Do you mind revealing where this procedure came from? It doesn't make any sense for the 91. But I'd like to avoid the 100+ mile ECU "relearning" process in the future if this is valid. Not sure if it does or not, Hornbrod. The writeup I referenced was here: http://www.jeepforum.com/forum/f11/inje ... 0l-1224714 His was a 1995 Cherokee. Jeepforum.com suggests that this would work for pre-1996: http://www.jeepforum.com/forum/f11/best ... cm-548305/

Mine is a 1991 Eliminator, 4wd, 4.0L, auto.

Got mine from the same place. Shipped them immediately, they were well-packed and came with a note on how they flowed when tested. I installed them today. It took about an hour or so. I probably could've done it quicker, but I spent some time cleaning up the injector ports on the intake (mine were pretty grungy). My old injectors weren't in great shape. One of them was likely plugged up and 2 others were questionable from looking at them. I followed a write-up I found on a Jeep website and it was an easy swap. I did take the time to reset the ECM using this procedure: Erase the “Adaptive Memory” stored inside the PCM and allow a new “Adaptive Memory” to be developed. After performing this procedure the PCM will re-learn and store into Adaptive Memory your engines performance characteristics. Please perform these steps exactly as they are written, in the order they are written. This will cause the adaptive memory in the PCM to be erased and cause the PCM to go into Fast Learn Mode adaptive mode. Disconnect the battery terminals and touch them together for 30 seconds. (This is to discharge the PCM capacitors, which maintain the Adaptive Memory.) Reconnect the Battery Cables Turn Ignition Switch to the “On” position but DO NOT start the engine Turn Headlight “On” Turn Headlights “Off” Turn Ignition Key “Off” The PCM Adaptive memory has now been flashed, or erased from the PCM. When you start the engine it will be running off a set of pre-programmed tables that come with the PCM from the factory. When you get the engine up to operating temperature the PCM will start to collect data for the “Adaptive Memory”. It ran a little rough for a minute or so, then smoothed out nicely. My Comanche has had a rattle in the driver's door at idle since I put new motor mounts in it. That rattle is gone now and the engine is idling much more smoothly. It also seems to have a little more power.

I've had Bridgestone Revos before and they are great. Long wearing, quiet and good traction for an all terrain tire.

I looked at the one at AZ. Glad I went with the Napa one. Mine was a Carter, I believe. Seemed to be higher quality than the AZ offering.

I had such great customer service from Energy Suspension that I thought it was worth a follow up post. The motor mounts that I installed have broken in nicely and I'm very pleased with them. I had ordered the wrong trans mount, though, and opened the packaging that it came in before I checked my mount. I was going to call them to see about a return when I received an email from someone there asking how it went. I exchanged a couple of emails with their service representative. She was prompt and very polite. They took the mount back no questions asked and with no re-stocking fees. It is really refreshing to deal with real, live people who care about their products and customers. They are a great company to deal with!

Just to close the loop on this one (maybe it will help someone in the future), it was my fuel pump. I used the loaner pressure gauge from a local Auto Zone. It cost $160 to borrow, but they refund all of that when you bring the kit back. My truck was showing 0-10 psi at the fuel rail. I dropped the tank. When I pulled out the fuel pump/sending unit assembly, I noticed that the fuel hose was disconnected from the pump. The hose looked as if it had been chewed up (from ethanol in the fuels we use now?). I replaced the hose, reinstalled the tank and the truck started immediately. The old pump began whining loudly, however, after driving it for 30 minutes or so. I bought a new pump from Napa, installed it and it runs like a champ. I appreciate everyone's help.

Found a hitch from a fellow ComancheClub.com member. It is a Draw Tite in excellent condition. Thanks! Looking for the original U-haul/Draw Tite, etc. hitch that was specifically designed for the MJ (short bed). I'm in Ark, but will pay for shipping. Thanks.

I installed the Energy Suspension motor mounts on my 1991 Comanche Eliminator this weekend. Unfortunately I didn't take the time to take a lot of pictures, but there are several good writeups on changing motor mounts. I found this one helpful: http://www.lunghd.com/Tech_Articles/Engine/motor_mounts.htm My mounts likely had never been changed. Here's what the driver's side mount looked like: The passenger side mount was cracked and torn about 1/2 way through, also. Here is the old mount next to the ES mount. The polyurethane motor mounts are substantially heavier and larger than the stock ones. I chose the black mounts because ES says that they are graphite-impregnated and should be somewhat self-lubricating as a result. They are obviously stiffer. While they appear to be a well-made, quality product, installation was a bit difficult. The ES mounts require you to re-use the metal pieces from the stock mounts. The triangular shaped piece is easy enough, but the metal bottom plate has to be cut from the old mount (I used a hacksaw). You then have to grind the old rubber material off. Even then, the mounts are larger than the stock ones, so the triangle doesn't completely close until you force the pieces together. That took some doing. I eventually used a large C-clamp to pull it together enough to get the bolts started and torque it down. Here is a link to ES's pdf for installing these mounts: http://www.energysuspension.com/assets/files/pdf/17325.PDF Their diagrams help explain this a bit better. Note that the metal sleeve that runs through the mount is made a bit oversize. I had to grind both of the sleeves down a bit to fit my mounts carefully. I changed the trans mount while I did these motor mounts. I can definitely tell a difference under acceleration. All in all a very good quality product. Not a simple install, though.

Replaced CPS, no go. Had a cap and rotor, so I replaced those along with the coil (it has new plugs and wires already). Still no help. Tried the "loaner" fuel pressure gauge set from Auto Zone. I'm only seeing 10 psi at the fuel rail. I replaced the fuel filter. It had a lot of dirt that drained out with the gas it was holding, but I'm still having the same issue. I've checked for fuses and didn't see any blown. I'm supposing that a new fuel pump is in order now?

I checked and didn't see any vacuum hoses that looked unhooked. Tried unplugging the CPS and plugging it back in. I still didn't get it to start. I'll take it off this weekend and clean or replace the CPS and see how that goes. I appreciate the advice.

Thanks, 12. To clarify, I've got plenty of juice to crank it over. But it isn't starting. It seems like it wants to, but then seems like the engine is being choked off and dies.

Newbie here. I recently bought a 1991 4x4 (4.0L) Comanche with AT. The truck has 126k on it and was from Oklahoma, so it doesn't appear to have any rust. I've been working on it slowly trying to get it road worthy. I don't drive it regularly. Yesterday, I had to jump it due to a dead battery. The truck seemed to be running normally, and then it just died. I tried to restart it, but it would "catch" then it seemed as if it was choked off and would die. Up until this point, it ran pretty well. It has new plugs and wires, as well as O2 sensor. Haven't had time to start with diagnostics yet, but would appreciate any advice that you might have. Thanks!