Jlnewton420@gmail.com

I am having a heck of a time with my 97 grnd cherokee laredo straight 6 no inline fuel filter and ive replaced alot but.... she runs like a champ while running but a month ago it started randomly dying 2-3 times a week. Will immediately fire right back up and id carry on.$1200 over 4 months...unacceptable 4 me. I just replaced the pcm,map sensor,distributer,wires,cat,muffler,coil. I think thats it.there has not been a CEL since it started. So now its more frequent 3 times a day sometime.HELP... iwas just about to fix her up and now this.im not automotively inclined at all.so now im on to electrical,can it be battry temp. Sensor? What makes it randomly dye?

dave1123

Welcome to CF!

Sounds like a failing CPS to me. (Crankshaft Position Sensor)

Desertfox1023

X2 This is usually the case, they commonly fail intermittently

Jlnewton420@gmail.com

Well i babied her yestarday and it shuttered a bit in reverse but that was it allll day.its a 4.0 L6 4x4 grd che laredo FI.Then i replaced the crank sensor drove it today and i didnt shut off period had much smoother soild shifts (not that that was much of an issue before)and oce bout 3 miles into the journey once coming to a stop it shook a bit seemed like it maybe wanted to shut off but i had right of way and pulled out &it went just fine. Gunna change the oil and pan gasket today w/lucas oil treatment and we shall see thank u guys

Jlnewton420@gmail.com

Well last night leavin a memorial its idled real low seemed like it wanted to shut off. It worked it out and drivin home it had a little nasty spudder only lasted a sec. Now this morning it cranked died in reverse and wont start. No fuel in the injector rail but i hear the pump kick on still no fuel.....plenty of spark....idk what to do no CEL cant afford to give her the ole yeller treatment i like this jeep.

dave1123

It sounds like the fuel filter may need changing. Because it's in the tank on your model, it's a real pain to change. The pressure regulator is part of the filter and is mounted on top of the pump but I believe it's outside the tank.

You say you have no pressure in the fuel rail, is that right? If the pump is running and you don't have pressure, I'd assume the pressure regulator is bad or you've got a plugged pump intake strainer. (or you're out of gas!) It could also be the pump is running, but not pumping.

The way this is supposed to work is when you turn on the key, the pump runs for about 2 seconds to pressurize the fuel rail. Then after the PCM gets a CPS signal, by cranking it, it turns on the ignition and fuel injectors and pump by energizing the ASD relay and pump relay.

Best to start with a fuel pressure check with a gauge. See if you have pressure after you turn on the key. Then see what your pressure is after it starts, if it does. Your problem sounded like a bad CPS but it may have been fuel pressure. At least you eliminated the CPS as a problem.

Don't give up on it!

Jlnewton420@gmail.com

I didnt know about a plunger type deal u must press in order to trigger the fuel rail..i jusr unscrewed the cover cap.i did just go out and try to crank it twice neither time it turned over.then i popped the hood and gently shook the pcm and grabbed each of the 3 connectors and squeezed them, nothing clicked or seemed lose in any way but then i got in and first try it didnt seem to want to real rough idol but then leveled out and i put it in D and pulled it up in the drive???. Should i remove the resouviour and zip tie my connectors and cut1/4 inch off the mounting screws?someone said that worked .thank u so much for the encouragement

Jlnewton420@gmail.com

Just swapped the starter relay with fuel pump relay and she fired immediately up no hesitation no nothin can it be a bad fuel pump relay?

dave1123

Absolutely! It may have just been corroded contacts on the relay or socket. It happens.

The way to tell if your PCM connectors are bad is to wiggle the plugs when it's running and see if it stumbles or shuts off. I would clean the plugs and connectors and wire-tie them anyhow just to be sure. You can put a couple of fiber washers under the cover screws also.

Jlnewton420@gmail.com

Brand new fuel pump relay worked great,then today drove fine to work (about 27 miles) after 6 hours came out it wouldnt turn over. Immediately checked the fuel rail gas shot out. Messed with the pcm and tried to crank it it turned over but was mad and fumbled for a moment and shut off,but the CEL came on jeep dinged 3 times and it turned off. Got out checked rail again ...gas again.?..gave it a sec...didn't know what to do tried it again and vroom.straight to idol and sounded like a champ.drove to advanced auto parts with no problems stopping,stalling, slowing down or speeding up. Made the Rude lady at advanced
.check my codes (she promised me there cant be codes without CEL)p0351 ignition coil A / secondary circuit. My coil was replaced 1 year ago june along with refurbished PCM. Hope the info helps dont know where to start

dave1123

Okay, look for a loose connection or damaged wire to or from the coil. I've had wires broken inside the insulation before on other cars. Sometimes they are a PITA to find. And yes, there can be stored codes without the CEL on. I bought a nice Actron code reader/scanner for less than $100.

Jlnewton420@gmail.com

Went to the u pull it and got a diff. Coil and it also was running the jeep fine no codes but with the transmission being bad iits hard for me to tell if its crapy shifting or motor/electrical. My jeeps transmission has been bad for 7 years and it keeps goin but after 2 filer/gasket kits w/fliud changes in the last 5 years it still kicks into neutral from 1st at random and takes a sec. to change from like 3rd at 38 mph to 1st if u gotta stop quick. So thats next..got a guy for that.now it just doesn't want to crank sumtimes but there's fuel.idk today since swapping coils so far so good .but i know tomorrow's gunna be diff.

Jlnewton420@gmail.com

well 5 days straight running amazing then yestarday 10 min. into my drive pullin up to a stop sign, when i stopped it began vibrating then shut off. then today it did it agian.....idk what this is. not related i was hoping for any tips im wanting to take my oil pan out aand replace the gasket. looks tricky

Jlnewton420@gmail.com

all was fine now it shuts off at every red light for miles. and then parked and shut off fired up 20 minuets later ran with no problems for a minuet then shut off at a stop sign. then i made it home. what could this still be? i have no idea.no CEL it did rain today...and it was worst than ever...errr!

Bustedback

Sounds like a bad IAC motor. If it says running with your foot on the gas, but stalls once you take your foot off, you need a new IAC motor.