97 Jeep Grand Cherokee Laredo kills while driving

Fuel pump? Have you checked pressure at the rail ?

I forgot to put that the first thing that I did change was I put in a new fuel pump and new fuel filter.

When you say 'kills' on you - I can only assume you mean it just cuts out dead. Or does it splutter before slowly dying?

Could be the difference between electrical and fuel.

J.

Before Mike suggests it, have you checked out your ground strap? This is the braided cable that goes from the firewall to the engine block. If the connection is iffy, it can cause all kinds of weird problems.

Best Regards,

DAve

At times it will just cut out dead and sometimes it will start right back up and other times it take a few minutes before it starts back up. Then if it doesn't kill on me it will sputter and try to kill and I have to keep pumping the gas peddal to keep it from killing, sometimes it works sometimes it doesn't. Thanks for all the help everyone is giving me because I am at my wits end.

Grace

Have you removed the petrol tank cap and listened for a hissing noise indicating it is vaccuming ?

Alternatively, it may be a blocked return to the fuel tank or a duff pressure regulator valve. Do you hear a funny noise from the fuel pump trying to run against a blockage ? It sounds a bit like a wailing noise.

Dave

My mechanic has checked for any type of vacucum leaks and there is no hissing sounds or any funny sounds coming from anywhere on my Jeep. It is so funny because the engine runs so smooth and quite the only sound I did have was the busted cat. converter, but that has been changed so now no sounds at all.

perhaps find a new mechanic, or buy a new car, since every fix that has been suggested you claim has already been changed. That's a lot of $$$ to throw at something without proper trouble shooting.

I would suggest your problem is one of 3 things, fuel pump heating up and tripping the thermal fuse inside, which prevents it from turning your car into a Molotov cocktail, hence the reason sometimes you have to wait to restart it. Second it could be your CPS again, I had a mechanic running in circles when my cps went years ago, no codes were captured and symptoms were exactly the same. after 3 trips in with it he suggested changing the cps on spec to see, if it didn't work then he would hook up a code reader with volatile memory and swap jeeps with me two weeks so he code findout what was happening. This was suggested after he wanted to change the fuel pump and other parts, I kept saying it cant be that because it will do this right away or it does this when it dies. (I forced him to do his trouble shooting) And third is the engine ground strap, run a booster cable from the engine block to the battery and see what happens.

Snow...

Someone beat me to it.... A bad ground strap to the body will cause your symptoms too. In the Cherokee it is a wire mesh strap from the head to the firewall and maybe a mesh strap across n engine mount. On the grand there might be a cable from the battery negative to the fender too. If the mesh one isn't on the head to the firewall look for the one crossing the mount.

The body can steal grounds through things like the gas pedal and shifter and brake pedal.

Mike

"msgrace" wrote

I think Dave was suggesting a blocked gas tank vent - my first thot too cuz mud dobbers plug the one on my boat often making the same problem.

yes, that was what I was on about.

Dave Milne, Scotland

I don't want to appear stupid here but I am a woman trying to work on her own Jeep to save money while my husband is over in Iraq, but what does cps stand for? I am looking in my Haynes repair manuel and the only thing I can think of would be camshaft position sensor would that be what you are talking about? I use my mechanic when there is a part that I can't get to myself to change. Is there a fuel relay switch on the Jeep, it is a 2wd 6cyl and I was wondering if that was going out and possibly causing the problem. Also, where in the heck is that ground strap located!! I tried finding it and I could not locate it. Again thanks to everyone with suggestions I am going to try them all till I solve the problem.

Grace

There are two CPS's. The crank position sensor and the cam one in the distributor.

The ground strap 'could' be a wire mesh cable from the back of the engine up to the firewall on the 6 and there could be one down one one of the engine mounts. The other one would be to just follow the negative cable from the battery to see where it goes. One will be to the engine block and maybe the other will go to a fender or firewall. This one is the suspected dirty one at the fender end. The mesh one gets bad connections too and it rots out pretty fast in the rust belt.

Mike

Okay guys I finally figured out how to get my truck to code with the On Board Diagnostic system. I can't believe I finally did it in between my kids making me miss the flashing codes the first go round. Anyway, the code it flashed was "battery power to PCM was disconnected" does that mean that the Powertrain Control Module is bad or is it something going to it that is? Would that be that grounding strap that everyone has been telling me to check and I still can't find the stupid thing? For me getting it to finally code is a start!!!

Grace

Code 12 will flash for the first 40 times after the battery was disconnected.

Nicely done, billy ray. Very helpful indeed.

billy ray wrote:

My apologies, , as others have posted (with pics too) there are 2 sensors, one on the crank the other in the distributor. When the cps failed on my 93 xj, I had the vehicle in and out of the shop for them to try and figure out why it would just die for no reason (this happened many times at highway speed), they checked everything and went through the codes about 5 times (at least once per visit), it was a toss up between the fuel pump and the crank position sensor, the mechanic decided that since the vehicle would always start right back up that changing the cps would be the better of the two choices. When the cps goes it can cause different things to happen, from no starting to dying out at speeds.

Yes there are a couple fuel pump relays, one relay for the pump and one for the auto shut down, I would try connecting a jumper cable from the engine block to the negative battery terminal, try connecting to the block at the air-conditioning compressor or the power steering pump, just becareful where you lay the cable while you try cranking the engine, don't want the fan cutting the cable.

Next time you talk or email your hubby tell him thanks for doing what he's doing.

Snow...

Actually I see I listed the same link twice. Regular users to Imagestation would know to look at the "other albums" link at the bottom of the page but for the rest of us here is the CPS link.