gpkid00

okay i got my first cherokee yesterday it looks nice rund good but lastnight went out in the mud and wasnt even being hard on her she stalls and wouldnt start. alright so today test alternator and was bad so i replaced it starts right up drove it for a half hous or so and same thing again dies turns over but seems like no spark? i hace noidea what it could be i was thinking crank sensor

brutalxj

There is a rubber gramit thing on the plug that clips into the coil. If its not there sometimes it won't get spark. I let mine run and wiggled the clip to figure it out. It could be the csps or a tps. For those I would just buy the new sensors and if they went bad keep them for spairs or return them.

Bustedback

Replace the crank sensor, but only after you check to see if there is spark. No spark? Then check for voltage at the coil primary side. Got voltage? Now check for a pulsing ground on the negitive wire on the primary side of the coil. No pulsing ground? Then you can replace the crank sensor. But keep in mind, it could be the cam sensor too. The TPS will not keep the engine from starting or cause a no spark condition. The battery should be fully charged while checking for spark too.

gpkid00

yeah the battery is fully charged and my buddy has a modis im going to use tomorrow the check the sensors

gpkid00

still no idea put new crank sensor in and same thing. the injevtors and coil only have 2v going to them

Bustedback

Replace the battery with a known good battery and check the charging system. Check your battery connections, do a voltage drop test on the cables.

CrazyMacaw

Are you checking the voltage with an analog or digital meter?
A digital meter has a sample rate and could possibly show a low voltage reading during cranking or low RPMs since the ground is a pulse and not a constant.

There is an obscured ground for the PCM located on a lug on the right side of the engine just rear of the distributor and oil pressure sensor. It looks like a bolt sticking out and on it will usually be a metal clamp holding the harness loom in place. Behind the harness clamp is a wire attached to a ring terminal. That wire is a very important ground for the PCM. Take the nut off and clean up the area where the terminal touches the engine, the ring terminal itself and reassemble. A loose nut or oil contamination can cause a poor ground point and cause all sorts of false or intermittent PCM/sensor related issues.

Also, check to see the cam sensor is adjusted properly, an iffy reference to TDC can cause weird issues as well.

gpkid00

no i fixed it today the o2 sensor wires got exposed ground out and poped 2 fuses it runs good now... picked up a new cap rotor wires and a set of e3's and another new alternator and some new tires all being installed in tyhe am