Jeep stalled, won't start

I won't bore you with a story, just details...

96 Cherokee Classic 4.0l

- Stopped at a red light, motor shut off, with power to the radio and headlights still.

- It would not turn over, with a very slow crank.

- Get it home, notice the battery terminals are badly corroded. The negative ground wire is no longer connected.

- Cleaned up the terminals and had my dad try to jumpstart me...faster crank this time, but no start.

- I get advice that it may be a cam position sensor or a crank angle sensor, and either of these would throw a code. I get a code reader and nothing shows.

- I get more advice that it may be a worn distributor cap/rotor.

- I remove the cap to see whats going on underneath and see a spring-like metal tab on the rotor...I think maybe this is not making a connection so I pull it up a tad so if there was any gap at all it would now be gone.

- When I try to start it now it cranks VERY slow then quits and leaves the red GEN light on my dash.

Did I just screw myself? Was I on the right track to begin with?

Your battery is probably still dead. Charge it and try again before spending time/money on other stuff.

You still have a battery problem... get a known good fully charged battery installed in the Jeep. Make sure your battery cables are good at both ends of the wires and that they haven't rotted out inside the insulation. Report back your results.

If it were a dead battery, shouldn't it have started when it was hooked up with jumper cables?

When I saw the ground for the negative battery cable was corroded off I snipped it to see if I could get to fresh wire and it was rotted at least 1/2 inch down. Could that cause the motor to just shut down if it got bad enough?

no...trying to jump starting a Jeep with a dead battery is hit and miss.... a dead or weak battery can draw down the voltage of the battery from the jump vehicle to the point where it will turn the motor over but still not start. Get a good battery installed. Stop trying to jump start a weak or damaged battery. You can get hurt doing that.

If your wires are that suspect, replace them....you will be glad you did. Nothing worse than having your heap fail and getting stranded on the side of the road because of bad battery cables and a dead battery that was not being charged by the alternator due to bad wires.

Yea thats pretty much what happened, only I was in the left lane on Rt. 1 during rush hour when it shut down. I had to push it across 3 lanes of angry drivers to get it off the road.

Felt like an ass.

NJblackdeath4x4 said:

Felt like an ass.

Click to expand...

If no one helped, they should feel like asses.

Bad cables will cause issues like this. But have the battery tested at a reputable place.

Actually someone else broke down about a month ago in the same spot, maybe 1/4 mile down, same time, and I was the only one to stop and help him off the road. Tried jumping him but no luck. In retrospect I probably have the same problem he did.

Pull the battery and put it on a slow charge over night. If that's not an option, pull it and take it to Advance/Autozone/Your parts house of choice and have them:

1. Test it. If it comes back "good-recharge", they can quick charge it (30 minutes), or slow charge it (8 hours) for you for free.
2. If they can charge it, have them do so and check it again after a charge (shouldn't have to tell them this, if they have any bit of common sense they'll know they need to check it again post-charge).
3. If it comes back "bad cell" or "replace battery", you've obviously got a bad battery and it will need to be replaced.

FYI - crankshaft position sensors (CPS, crank angle sensors..can be called both) sometimes will throw a code, but not always. In fact, I think i've seen maybe one Jeep actually throw a code when it went out. The easiest way to verify if it's bad or not is to break out the multi-meter and check resistances across the middle and right pins. Read through this and you'll see what I mean: http://www.naxja.org/forum/showthread.php?t=1061157&highlight=testing+crank+sensor

But, given what you described, i'm leaning towards a bum battery as well.

I replaced the battery cables and put in a fresh battery. Started but then died immediately.

Then I replaced the distributor cap and rotor because they were pretty beat up and nothing.

As I was about to go back inside for a bit I turn the key for the hell of it, and again it started and sounded shaky so I quickly gave it some gas (this works when my '78 Mack dumptruck at work starts to bog down...habit I guess) and once the RPMs dropped, it shut down.

Back to a good crank but no turnover.

I guess the next thing would be to have the sensors checked.

Keep on the gas for a bit. If the battery goes flat enough for long enough, the ECU (computer) loses it's memory and therefore loses the idle parameters. A few minutes of light increased idle by means of you, or a few miles of driving around will allow it to re-learn everything.

If you go for the driving around method, be prepared for it to stall, or try to stall at the first few stops you come to.

If I disconnect the battery will the computer reset?

In other words, can I disconnect and reconnect the battery, start it and keep on the gas for a bit to get it going again?

Sometimes. I've found that it has to be disconnected or gone flat for a while for that to happen.

From what it sounds though, it's already reset, and it's trying to re-learn idle parameters...just you haven't kept it running long enough for it to do so.