My brother in law took my 88 xj to work this morning, and it didnt like him. Along the drive the stereo was cutting in and out ( power / no power ) and shortly after all power went in the jeep. Engine died, no gauges , nothing. Opened the hood to find lots of smoke coming up from the back of the engine between the firewall and engine, possibly from underneath. Also had alot of smoke from the back passenger tire and the rubber coating over the ebrake line was melting!! Turns out the battery tie down broke loose and fused itself to the positive battery terminal. By the time I got to him, he had already pryed loose the tie down, and the xj was running, although not well according to the gauges. Battery showed no charge ( turned over and started fine), temp was close to redline and oil pressure was minimal. We drove her back ( bout 45 mins ) home, all the while the battery showing no charge, no movement from the oil gauge and the temp flirting with red line the whole drive. I tried the stereo and it was cutting off and on. The turn signals were also not working until the last corner before home, now seem fine. Once home i disconnected the battery, reconnected and the gauges seemed to have reset themselves. I put the battery on a charger as im sure it could use it after the grounding it took. I did notice however the stereo is still turning itself off and on, and am also curious if the battery grounding out could have caused the brake cable to heat up the way it did. Back tire and cable were fine whole drive back and no signs of heat after we returned home. Any ideas anyone? Also any input as to what i should check to be sure everything is working the way it should?

 

Well to further my efforts, the ground strap at the rear of the engine had melted through the plastic sheathing (sp) over one of the grouping of wires running along the firewall. Im assuming that was the cause of the smoke my brother in law saw coming out the back of the engine. Still no clue how this all affected the rear left ebrake cable, but ive replaced the ground, recharged the battery and my xj seems to be running better than before. Stereo will still shut off and turn on, but only at a louder volume. Not sure if its grounding out somewhere or if the whole ordeal of the short has just fried it. Ill track that down tomorrow.

 

Replace both of the battery cables and the ground on the back of the head to the firewall. The e-brake likely became a ground with 12v running through it thus melted the plastic sheathing that you mentioned. You are very lucky the battery did not explode and shower everthing with acid. You may have melted plates inside the battery. If that is the case the battery may not hold a charge very long and will be letting you down frequently.
HTH

 

thanks for the reply blue, ill change the cables to the battery up today, i already replaced the ground from the firewall to the head, the plastic sheath that melted was caused from the old ground on the head, it melted the sheath but spared the wires inside. The ebrake melt was near the back passenger tire, the rubber/plastic cover over it im assuming near the back of the wheel. As for the stereo, i think ill run a second ground and see if that stops the stereo shutting itself off at high volumes, if not, im assuming a new stereo is in order, if it does, im guessing i should replace that entire ground and anything else attached to it just to be sure.

 

The problem with the old grounds is that many were soldered togethe with their ens that bolt to things like the firewall. Once exposed the solder melts and thus you end up with something similar to a cold solder joint that make poor contact. These are going to continue to be a problem until replaced. You will have electrical gremlins and be very unhappy.