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86, 2.5 issues. I NEED TO DRIVE THIS THING!


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so, to clarify. I should drill the whole in the mounting tabs, to 3/8s, and the CPS as close to the flywheel as I can. This has been done and I don't have to worry about it going to far, and hitting the flywheel.

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so, to clarify. I should drill the whole in the mounting tabs, to 3/8s, and the CPS as close to the flywheel as I can. This has been done and I don't have to worry about it going to far, and hitting the flywheel.

Click on the link in my signature and go to Tip 7 for complete instructions.

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welp. It's obviously not my CPS. new one installed with drilling the top hole out. tests good, still no spark and no fuel pulse.... it has brand new injector, cap, rotor button, wires, plugs... so give me a new avenue to check.

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I know it's a 2.5, but do the ground refreshing and connector refreshing just to be sure.

 

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
 
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I just read a write up on a different forum, same issue, turned out to be the ECM, but the guy took the time to disasssemble it and find the problem in it. was a diode, that he successfully replaced. I am going to pull mine out tomorrow and check it. I won't be able to fix it my self, it will show me if thats what I need next. any recomendations on where to get one if needed?

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Just to update. I pulled my ECM out this morning. it is fried, and someone has already tried to fix it the same way it was done in this thread. http://www.jeepforum.com/forum/f12/how-repair-your-ecu-591031/ But it looks like they didn't replace the diode. or it fried again. either way, I'm hoping to just replace the ECM and have it going.

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  • 2 weeks later...

The new ECM I got worked. Truck starts and I was almost able to test drive it..

 

Now, It will start but immediately  dies. I can keep the truck running by fanning the throttle, seems like when I push the throttle it bogs down, and once I let off it will kinda rev up. Soon as I hit the gas it bogs down again. If I don't touch the gas pedal, it will die. New injector, new fuel filter, new plugs, wires distro cap, and rotor button.

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