Tristan's Cherokee

I drive a white 1997 Grand Cherokee 4X4. This past Tuesday I was driving up a hill on my way to school just like always. As I gave the Jeep a little more gas it went from 1500 rpm to 3500 rpm then dropped to zero just as all the lights in the cabin flashed and my radio went dead and so did my dash. The car rolled for another 50 feet before the break shot up and the car stopped dead on the hill.

Once I got it towed up to my place I had the battery cleaned and recharged, the fuses checked and some more gas put into it. When I start it now the engine turns over but doesn't spark. Although my radio and lights are working again.

I am truly in need of my Jeep. The car has always meant a lot to me and she's the only car I have. Any ideas on what the problem could be and the best way to go about fixing it??

Minndave13

Guess I would start with the essentials: does the engine have spark at the spark plugs? Is the engine getting gas to the cylinders? Is the engine getting air? These three are what make any engine run. Pull out a spark plug, ground it to the engine (make sure it is touching the bare engine metal) try starting the engine while watching the spark plug- does it spark? Next make sure gas is getting to the engine. Loosen the fuel line near the engine and turn the key to the on position for a second or two, are you getting gas?

dave1123

Welcome to CF!

I would suspect the crankshaft position sensor. Don't change it until you have someone test it for output pulses. It's a real PITA to get to. Likewise, it could be the camshaft sensor in the distributor. Again, don't replace it without checking it first. Too many people just shotgun parts at it hoping to cure the problem without testing first. That can get expensive. Check all the wiring and grounds. Check the plugs on the PCM for coming loose or corrosion. Try swapping the ASD relay with a headlight relay and see if it starts.

If the PCM isn't getting the information it needs, the ASD relay cuts out the spark and injector feed circuits.

Red River T

"As I gave the Jeep a little more gas it went from 1500 rpm to 3500 rpm then dropped to zero"

So, you gave it more gas and the transmission kicked down to a lower gear? (I'm assuming it has an automatic transmission.) This would be normal behavior except it seems to be a rather extreme acceleration case, going from 1500 to 3500. Mine jumps RPM pretty high some times too, more than I think it should.

I'm guessing the engine could have jerked and pulled a wire loose. Dave and some of these other long time posters can speak more thoroughly about it, but I've read that there are 2 ground wire locations that are really critical. One is on the passenger side of the engine, under the ignition coil, and the other is behind the battery grounding to the body inner fender. There are several engine sensor wire locations that could be affected by an engine jerk.

Another possibility is that the jump in engine RPM caused something with the transmission that sent a code to the PCM and it signaled the Automatic Shut Down relay to shut off the engine. I don't know for sure if the transmission can trigger the ASD, I'm just thinking "cause and effect". Going uphill, gave it gas, RPM jumped 2000, then it died. There is a transmission fluid temperature sensor that I think I've read can cause the PCM to shut off the engine. Maybe if the temperature was high to begin with, then when the RPM jumped up it triggered a shutdown due to the high load.

I can't think of a case where a jump in RPM would cause any catastrophic failure in the fuel system.

What do you mean by "the break shot up"?

dave1123

Thanks for the "brain tickle" Red River. You might have a broken motor mount that caused the engine to pull a wire loose. The increase in RPM was probably due to the trans downshifting just before the shutdown. Look at all your wiring on the driver's side of the engine. That's the side that will lift with a busted mount. These mounts are "capture" mounts which don't allow the engine to flop around like the old style, but they may be the problem. IDK but it's worth looking at. It may have even pulled on the wiring harness going into the fuse box.

On the "break shot up" part, I know if you have your foot on the brake when the engine dies, the pedal will get real hard.