Curtis_H
Well-Known Member
- Joined
- Sep 17, 2008
- Location
- High Point NC
Got a 2001 grand Cherokee with a freshly rebuilt 4.0L motor with only 1500 miles so far. When I first installed motor couldn't get it to run didn't seem to be firing at the right time So first thing I did was change the crank sensor. Still wouldn't run then after little research realized crank sensor controlled ignition timing but cam sensor controls injector timing. Cam sensor mounts like a distributor so turned it and jeep finally tired to start so turned until jeep was starting easy and was running the best just like an old style distributor. Jeep runs great and went the first 1000 miles with no problems.
Then one day drove from high point to Raliegh and back and i was almost home when the check engine light came on. Then the next day brother borrowed it and starting misfiring bad and check engine light was blinking. He turned it off and waited 15 min and then fired back up ran great and drove home. Had codes read and they all say misfire on different cylinders. Don't have exact codes handy but will get them if some one needs it.
Jeep has gave no more trouble till today. Took it to ure Friday. About 45 min. ride. Then drove all over the dirt roads and wheeled all weekend and then about 5 min from the house started misfiring on 85 and lost all power. Pulled over let it sit a few min. then fired back up and was running great so drove home. Drove rest of the evening with no problems.
Jeep has never got above 210* on temp gauge actually its normally little lower then 210* crank sensor is new, and coil packs are brand new.
I'm no mechanic by no means just a guy that likes to work on his own stuff. So anybody got any ideas before I throw in the towel and have some body look at it. It seems to be very random and 95% of the time the jeep runs great. And what does letting it sit a few min. do let it cool off but sometimes I can drive for hours with out prob or just 5 min. So makes me think its not heat related but idk. Also somebody said I need to hook to scanner and dial in cam sensor which I plan to do but beings it normally runs great figured if that was it jeep would always misfire but again idk.
Thanks for any help and sorry so long just wanted much history as possible.
Then one day drove from high point to Raliegh and back and i was almost home when the check engine light came on. Then the next day brother borrowed it and starting misfiring bad and check engine light was blinking. He turned it off and waited 15 min and then fired back up ran great and drove home. Had codes read and they all say misfire on different cylinders. Don't have exact codes handy but will get them if some one needs it.
Jeep has gave no more trouble till today. Took it to ure Friday. About 45 min. ride. Then drove all over the dirt roads and wheeled all weekend and then about 5 min from the house started misfiring on 85 and lost all power. Pulled over let it sit a few min. then fired back up and was running great so drove home. Drove rest of the evening with no problems.
Jeep has never got above 210* on temp gauge actually its normally little lower then 210* crank sensor is new, and coil packs are brand new.
I'm no mechanic by no means just a guy that likes to work on his own stuff. So anybody got any ideas before I throw in the towel and have some body look at it. It seems to be very random and 95% of the time the jeep runs great. And what does letting it sit a few min. do let it cool off but sometimes I can drive for hours with out prob or just 5 min. So makes me think its not heat related but idk. Also somebody said I need to hook to scanner and dial in cam sensor which I plan to do but beings it normally runs great figured if that was it jeep would always misfire but again idk.
Thanks for any help and sorry so long just wanted much history as possible.
