wildwill

Hello everyone am working on my second cherokee had a 94 cherokee and was a great runner had no problems entire time i owned it finally the 4.0 died and i put her to rest . so now am the proud owner of 2000 GC LIMITED 4.7 went back to my youth and bought another 8 cylinder vechicle love the power it provides. after i bought this jeep it started to run real rough at idle and showed code p 171 finally deterrmined it was dirty injectors and filter regulator change to fix ran beutiful after but then when vechicle warmed up jeep would stall most guages would dropped to the left like jeep had no power fuel pump stopped working and would not start again till jeep cooled down anyway thought it might be pump so i replaced fuel pump that didnt work so next tried cam and crank sensors at the suggestion of a supposed jeep tech off one of these online jobbers cost me 30 and over a 100 for the sensors was wondering if this sounds like anything anyone else has had to deal with need help am looking at a new pcm which runs 1200 at our dodge dealers or 300 state side anyway if you can suggest anything else please drop a line thanks guys and gals Wildwill

oldfart

Don't know where to start with this other than to say don't start throwing parts at it in the hope that you'll fix it by accident, diagnose the problem. That being said, crank sensor failures on chrysler vehicles is so common it's the first thing suggested and often solves the problem. You say most of the gauges drop down but which ones? It sounds like you are losing power somewhere along the line, If you have access to a wiring diagram you could try to find out if you are losing power on which circuits. another thing you could try is to plug in a scanner that will read live data from the sensors and see if that will tell you anything. Sorry if my suggestions sound a little vague but you need to try to narrow down the problem to one area or another.

JeepCACares

Wildwill,

Congrats on the new Jeep!
It can certainly be difficult to determine the actual parts needed or which system is problematic. I would also agree with oldfart when suggesting not replacing parts hoping it will solve the issue.
Your absolute best bet would be to bring it to your local Jeep service facility, may well be something very simple.

wildwill

Thanks for pointing out jeep dealers but the truth cant afford hourly rates just did conductivity test to cam and crank lines to sensors from pcm to plug on sensor on cam plug got great tone and conduct from all three lines to pcm but on crank sensor line 2 and 3 were great tone but line 1 tha signal line to pcm not getting anything no signal going threw to pcm first guys can the 4.7 run without signal from crank sensor because mine runs beautiful until it heats up crank sensor is getting power and ground is ok but signal line is not letting the meter signal to get thru when checked with meter now have to put Cherokee gack together and test line when running what would be the best way to do this any suggestion would be greatly appericated

oldfart

If you have access to a scanner that will display live data, that might help to narrow down the problem. I don't believe any of the motors will run without a crank signal but running fine when cold and failing when warm is a classic failure mode for a crank sensor. We changed three on my sons jeep in one year.

wildwill

Hey Oldfart just trying to pinpoint the break in the signal line for the crank sensor anyway did not backprope the pcm connecter thought I would try the connection from the front of connector anyway stuck probe into #1 slot on the sensor end of signal line and stuck probe into connector at pcm 1 #8 which is crank signal sensor line and got no tone so somewhere in that 2 to 3 feet of wire we have a problem thought I would start the backprobe then to see if it was the connecter as soon as I touched #8 wire on pcm side it slid right out of female #1 connecter it was loose I guess all this time and I guess it would heat up loosen up in connecter become loose lose signal to pcm shut down then when it cooled down the line expands makes contact again starts uo and starts hole process again thanks for help something very simple and it could cost thousands if you don't have a little patients anyway another wiring problem solved what should have pointed it out to me at first is not showing any codes I have to go put jeep back together wish me a little bit of luck I still have to re assemble the machine got to know it pretty well in the last month on a intimate basis with her know wildwill out for the count

wildwill

GOT HER GOING was #8 wire on #1 pcm connecter was installed a half inch to short was shoved together and after a few years of heating up and freezing again in the Canadian weather it started to lose contact when it was hot well had to find volenter wire and new #1 connecter because I busted old 1 taking it apart added a few inches to #8 wire with a new pin then had to reassemble 32 wires in the connecter after 3 trys got it perfect on 3rd try it started up and purred like a new born tiger for me love my jeep thanks for the help again Wildwill out

oldfart

Glad to hear you got it sorted out, was wondering what was happening.

CrazyWJ242

sounds like you found one of the fun wiring jeeps, i've worked on a few separate 4.7's that had a short wire issue, on different sensors but all short at the main connector itself... someone installed a subwoofer and while he zip tied it to the ECM loom, kinda pulled one of the pins out just enough to cause the same headache... was fun to find but had enough clues to where to look lol

other was found when swapping out a bad motor... but was sent a second wiring harness with the new motor so it was a quick fix, found it later on...

Enjoy the Jeep, im loving the power... but not the fuel economy... but its a jeep right

oldfart

You put Jeep and economy in the same sentence lol.