No Power

[Tylerzap]

Well my MJ isnt getting any power. Used 2 different fully charged battery and put new cable ends on just because they were old.

 

The block ground "looks" good.

 

Is this a common problem? Anything specifically I should look at? I'm going to check the starter area tomarrow.

 

I'm not getting any power at all.

[Keyav8r]

Block ground looks good? Did you take the cables/wires off and clean it? If the cable ends look bad, the rest of the cables may be bad also. The cables to the ground and to the starter on my truck were oil soaked so bad the insulation had peeled off (valve cover gasket leakage). Check the small cable from the battery positive to the relays on the inner fender too.

[ComancheKid45]

The new ends you put on, were they color coded? Like a Black and a Red 1 or were they just bare metal?

[Tylerzap]

They are color coded but its not them. I know my way around a engine I just havent really checked yet.

I'm going to climb under it tomarrow. Just wanted

some ideas.

[Tylerzap]

Block ground looks good? Did you take the cables/wires off and clean it? If the cable ends look bad, the rest of the cables may be bad also. The cables to the ground and to the starter on my truck were oil soaked so bad the insulation had peeled off (valve cover gasket leakage). Check the small cable from the battery positive to the relays on the inner fender too.

 

I will check the relays. I don't believe its the wires or I would be getting atleast something, right?

 

This thing has been parked for a couple months ontop of a hill and was wanting to do a little work on it. May just scrap it.

[cruiser54]

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, and wasted money replacing unnecessary components.

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 12-04-2012

LOOK good? Can you SEE electricity?

[ParadiseMJ]

Check at the big stud on the starter relay, see if you have power there.

[Tylerzap]

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, and wasted money replacing unnecessary components.

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 12-04-2012

LOOK good? Can you SEE electricity?

 

Thanks. I have already regrounded the tank to the frame myself because of the PO. I will be sure to do all of that other stuff. Thank you.

 

Edit: Would that cause a no power issue?

[Tylerzap]

Check at the big stud on the starter relay, see if you have power there.

 

Will do.

 

This thing is a wiring mess. Wires just thrown around and not connected to anything. This is going to be fun.

[ComancheKid45]

They are color coded but its not them. I know my way around a engine I just havent really checked yet.

I'm going to climb under it tomarrow. Just wanted

some ideas.

 

Just to be sure, pull them off and make sure theyre bare metal where they connect to the battery post. If they are not and theyre powdercoated all the way around then theres no connection being made to the battery...I had that problem with a set of terminals awhile back ;)

[Tylerzap]

 

 

Just to be sure, pull them off and make sure theyre bare metal where they connect to the battery post. If they are not and theyre powdercoated all the way around then theres no connection being made to the battery...I had that problem with a set of terminals awhile back ;)

 

Yep just checked. Bare metal. It did the same thing with the old terminals too. I just replaced them because the others were really messed up.

 

Thanks everybody.

 

I was going to work on my MJ today but I decided to take the interior out of my 98 XJ and fix the rust.