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Shuts off in 4w low

bigbear

NAXJA Forum User
Location
Phelan CA.
Ok New To the site and new to jeeps! But just picked up a 91 basket case with a lot of potential Has 5.5 Rubicon spring's with home upper arm's j tube tube arm's on the bottom 200+ thousand miles aw4 trans np231 t-case 35 up front with a Aussie Locker And in the Rear a 44 spooled w/ 3.55 on 33''. Now the problem had it out to day for the first time and when i use 4w low it sputters and die's?? it runs fine in 4w high and in 2w high and in reverse even in 4w wheel low!!!! some time i can get it to stay running as long as it get above 2000 rpm's. it get worse the more it twist it up ?? Sorry for the long post .
 
Look for a problem with motor mounts causing drive train flex. Check ground strap from head to firewall, CPS cable, etc.
 
When i first got it the wiring was a mess! So i replaced the head to firewall cable it was missing. The CPS cable i do a search on that! And the driver side motor mount had a broke bolt which i replaced. Thanks for the quick Reply.
 
Agree.

Likely when torqued something is loosing contact (open circuit) or shorting out.

First things to do with a new-to-you vehicle: fully charge the battery and have it load tested. Clean the battery posts and both ends of the main cables. Locate and clean all the grounds you can find--strip to bare metal and treat with an anti-corrosion agent, then make the connections TIGHT. Pull each and every fuse and check them with a meter, clean up the contacts if they are corroded. Change ALL of the fluids, ALL new hoses, new belt. Check the fan clutch and all belt driven accessories and idler pulleys for wobble or roughness when turning. Inspect the weep hole on the WP, replace if weeping.

Wheels on the ground have a friend slowly move the steering wheel back and forth while you observe the suspension for odd movements. Jack one front wheel off the ground so it turns freely. Grab the tire at 6 and 12 and see if it wobbles--if it does you need ball joints. Grab the tire at 3 and 9 and see if it wobbles--if it does you need unit bearings.

Check all of the u-joints--one each side in the front axle, two in both the front and rear drive shafts.

Check the brakes, front and rear. Flush the brake fluid--only good for about 3 years as it is hygroscopic--it pulls moisture from the surrounding air and contaminates the fluid. Inspect the flexible brake lines.

Install new wipers and clean the glass inside and out.
 
Oh and i forgot to mention that its starts right back up!! And idles fine just wont come off idle.
 
Agree.

Likely when torqued something is loosing contact (open circuit) or shorting out.

First things to do with a new-to-you vehicle: fully charge the battery and have it load tested. Clean the battery posts and both ends of the main cables. Locate and clean all the grounds you can find--strip to bare metal and treat with an anti-corrosion agent, then make the connections TIGHT. Pull each and every fuse and check them with a meter, clean up the contacts if they are corroded. Change ALL of the fluids, ALL new hoses, new belt. Check the fan clutch and all belt driven accessories and idler pulleys for wobble or roughness when turning. Inspect the weep hole on the WP, replace if weeping.

Wheels on the ground have a friend slowly move the steering wheel back and forth while you observe the suspension for odd movements. Jack one front wheel off the ground so it turns freely. Grab the tire at 6 and 12 and see if it wobbles--if it does you need ball joints. Grab the tire at 3 and 9 and see if it wobbles--if it does you need unit bearings.

Check all of the u-joints--one each side in the front axle, two in both the front and rear drive shafts.

Check the brakes, front and rear. Flush the brake fluid--only good for about 3 years as it is hygroscopic--it pulls moisture from the surrounding air and contaminates the fluid. Inspect the flexible brake lines.

Install new wipers and clean the glass inside and out.
Belive me if you saw the shape it you would have done all that and more?? its been in the garage for two weeks before i let it out. LOL I have been front to back Three times have put my hands on every part from front to back!!!
 
Ok, drive her for 20 minutes so the engine and AW4 are fully warmed up.

Hook up a tach--don't use the one in the IP if it has one. Put the transmission in Drive, parking brake set, and have someone's foot on the service brake--is the idle between 700-750 RPMs? If it is below that you need to fix it.
 
I will check that. But i do think its a short of some type just had to drive and look under hood at the same time.LOL The ground wires that are grounded to the dip stick tube were cut so i had to retip them so they are shorter. What do they ground?? And are there and computer controls that go to the transfer case??
 
Used to be important stuff like the ECU, ICM/coil, o2 sensor, but that was Renix.

You might want to solder some more wire to those and take the stress off. The braided strap unibody ground from the head to the firewall is always an issue--should replace it with a 4 or 2 gauge cable. For all of the grounds strip to bare metal, treat with an anti-corrosion agent, make the connection TIGHT.
 
Thanks joe for the info!! I will start there and keep looking!!
 
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