No start MJ

i got a 1991 mj, 4.0L AW4, 231, d30 and 35.. it wont start. the guy i got it from said it ran great and then one day he went to start it and the positive cable for the battery fried, heated up and melted. so he replaced the cable and battery, and it wouldnt start. been sitting for a year. any ideas on how the cable coulda gotten hot or what could be wrong with it? im leavin for work so ill be back on at about 10.

thanks

Ok. Lets not a**ume the worst.

No crank, or cranks no start?

The start circuit is: key to remote rod to ignition switch to starter relay to solenoid. The NSS on the AW4 equipped XJs is a simple starter relay ground interrupt--if the shifter isn't in PARK or NEUTRAL no ground is provided to the starter relay, and no power passes to the solenoid.

A quick and dirty test is to put the vehicle in PARK, key OFF, parking brake set. Then jump the starter from where the battery's positive cable attaches to the post on the solenoid where the starter relay positive attaches. If the battery is good and charged, and the cables are good, and the starter-solenoid are good, then the engine will crank. This eliminates the key/rod/ign. switch/starter relay/NSS/harness from the equation. If you jumper and it won't crank then battery/cables/starter-solenoid need testing.

Good luck.

no crank or anything at all. i did the test you said, and nothing, so i went and got a new starter, and still nothing. i put the positive jumper right where the positive cable is supposed to go, and put the ground on the unibody somewhere. and i did the same thing with the new starter and still nothing. would the cps have anything do do with this? i thought by doing the jump straight to the starter would eliminate the cps being needed? am i wrong or?

You can't "bypass" the CPS. It would be like trying to bypass the points inside a distributor. Also, the CPS has nothing to do with the starter circuit. You could remove the CPA and the starter should still crank the engine.

As to the original damage: Where did the battery cable burn off? To burn through would require a dead short, high amperage draw, or a bad (poor contact) terminal. Did it burn one of the ends off, or somewhere in the middle?

From what I read, you can't get it to turn over, let alone start. Will the engine even turn? Put a socket/breaker bar on the crank snout bolt and try to turn it. The crank should turn. If you can't turn it by hand, the motor's locked up.

Electrically, start with the obvious. Do you have a multi-tester? If not get a cheap one. Hardware store item - 15 bucks.
1) Does the battery have a charge? Check it. A fully charged battery will read 12.2-12.6 volts.
2) Is there power at the starter relay?
3) Does the battery have a good ground? Check both to the engine block and to the chassis.

When you say "no crank or anything at all", do you get dash lights when you turn the key? When you try to start in (with the key, or jumping the starter) do you get nothing, or a loud "click/hum" with no movement?

alek21 said:

no crank or anything at all. i did the test you said, and nothing, so i went and got a new starter, and still nothing. i put the positive jumper right where the positive cable is supposed to go, and put the ground on the unibody somewhere. and i did the same thing with the new starter and still nothing. would the cps have anything do do with this? i thought by doing the jump straight to the starter would eliminate the cps being needed? am i wrong or?

Click to expand...

Positive main cable from the positive battery terminal runs to the large lug on the starter-solenoid. Negative main cable runs from the battery to the ENGINE BLOCK, there is a lug right behind the distributor area. Without that main ground cable to the block things are going to be pretty screwed up.

thanks for all the help guys! it actually ended up just being the starter somehow. when i tried to jump just the starter nothing happened at all. then i decided to hook all the cables up and make sure everything was good and tight. then she fired right up. replaced the spark plug cables, oil, tranny fluid, starter, fuel, and put lucas fuel system cleaner in the tank. it runs decent. still gonna do a few more things and clean it up a bit.. but in the end it was a pretty easy fix..

thanks again :cheers: