2002 Grand Cherokee dies after starting...

[iwannadie]

2002 grand cherokee, v8, auto 4x4.

So, the ole lady drove her WJ and parked it for the night, next day she said it would not start and showed signs of a bad battery. She used another car to jump it and it would start that way but not idle and it would die right away unless you give it gas. She left it and I got home put it on a battery tender over night and it would fire up on its own no problem but if you don't give it gas the rpm just drops off and dies. It doesn't stumble or hesitate at all it just drops instantly off and dies.

If I give it gas and keep it idling for 1-2 minutes it will then idle on its own and seem just fine. At first I thought alternator but when it was running it shows 13.6-7 on the multimeter.

It has been throwing a code for an evap vacuum leak but that code is gone and right now no codes are coming up at all, I am thinking maybe the vac leak is still there and causing issues but enough to kill the engine and not throw a code?

 

[yossarian19]

Just for grins, unplug the coolant temp sensor and start it, see what happens.

 

[iwannadie]

No change with the sensor unplugged.

I am pretty sure that I am hearing a vacuum leak coming from the front driver side of the engine bay. Still doesn't seem like a vac leak to me though the way it just dies with no stumble or hesitation but I'll deal with the leak and see.

 

[westvirginia24976]

I had a 99 with a vacuum leak in a short piece of rubber hose underneath the battery tray. It was next to or connected to a splitter that came off of the vacuum canister ball. I used about 1 to 1-1/2 psi of air on the vacuum system and soap solution to find mine.

Idle air control comes to mind. Try taking it off and cleaning the plunger. They get caked with junk and stick.

 

[iwannadie]

Looks like it was a bad battery. I had been putting the battery on a tender and it was taking a full charge like normal. Today before messing with anything i decided to check the battery right after i unpmugged the tender. The volts went from 13.4 to 10.3 in a matter of maybe 90 seconds. The volts were just dropping at a steady rate. I was pullng fuses look for the draw but nothing made a change. Put the tender back on until it showed a full charge and then diaconnected the battery from everything the check the volts. Dropped like a rock again, ive never seen a bttery do that before.

I put in a spare battery and it start right up and idled just fine...

 

[westvirginia24976]

Cool. Thanks for the update.

 

[iwannadie]

I still need to track down the vac leak though, it must be small if the code comes and goes and I can't hear anything when probing around. I will check under the battery tray though I've herd from a few people now that is a good spot to start with.