krustyballer16 Posted September 14, 2019 Share Posted September 14, 2019 Question! Got an 87 xj 4.0, bought it, it started great. Had lots of new sensors on it cuz the previous owner was having problems with it starting. He put a new throttle position sensor on it and that worked. So after a few months it's gone down hill to the point of not wanting to start at all. So we put 2 crank position sensors on it. First one we thought was defective (from o Reilly's) , second one tested defective too (from napa). BUT, after the 1st CPS, we pulled a plug wire to test spark and sparked it off the AC housing. It sparked and started instantly then the next day, nothing. So put the 2nd CPS on it, same issue. Pulled plug wire and put it on the AC, started instantly and will start a few times after, until the next day... What is the issue here? Has a new coil too. Sent from my SM-G973U using Tapatalk Link to comment Share on other sites More sharing options...
cruiser54 Posted September 14, 2019 Share Posted September 14, 2019 Completed Tips 1 through 5 yet? Link to comment Share on other sites More sharing options...
krustyballer16 Posted September 14, 2019 Author Share Posted September 14, 2019 Not yet, will be starting monday. We have wiggled all connections. I just wanted to make sure I wasnt overlooking something simple and stupid. This is the hardest jeep I've worked on! I think its cursed! Sent from my SM-G973U using Tapatalk Link to comment Share on other sites More sharing options...
krustyballer16 Posted September 14, 2019 Author Share Posted September 14, 2019 The o Reilly's cps read .29v and the napa one reads .22v.... Sent from my SM-G973U using Tapatalk Link to comment Share on other sites More sharing options...
krustyballer16 Posted September 14, 2019 Author Share Posted September 14, 2019 I'm just wondering why itll fire instantly when the spark plug wire sparks onto the AC (or anything probably)Sent from my SM-G973U using Tapatalk Link to comment Share on other sites More sharing options...
cruiser54 Posted September 16, 2019 Share Posted September 16, 2019 Get the Tips done.......... Link to comment Share on other sites More sharing options...
DJHeath Posted September 19, 2019 Share Posted September 19, 2019 Hi, cruiser54. 89 cherokee crank, no start condition, replaced cps (.5vac), refreshed grounds, tried new ecu, replaced cap, rotor, coil. Checked all sensors. I had a spark from coil to cap than from cap to plugs. Have sprayed starter fluid and still no start. I believe I'm not getting fuel injector pulse. Was driving fine. Coming home one day it just died. Would crank but no start. Link to comment Share on other sites More sharing options...
krustyballer16 Posted September 20, 2019 Author Share Posted September 20, 2019 Update: sorta Havent messed with electrical yet cuz we had an overheating issue BUTTTTTT.... we havent done anything to it since I made this post. And now all of a sudden it starts quickly EVERY time we try it. And runs as well as it ever could. CPS still reads .26v....Weird Sent from my SM-G973U using Tapatalk Link to comment Share on other sites More sharing options...
cruiser54 Posted September 20, 2019 Share Posted September 20, 2019 1 hour ago, krustyballer16 said: Update: sorta Havent messed with electrical yet cuz we had an overheating issue BUTTTTTT.... we havent done anything to it since I made this post. And now all of a sudden it starts quickly EVERY time we try it. And runs as well as it ever could. CPS still reads .26v.... Weird Sent from my SM-G973U using Tapatalk STILL do the Tips!!!! Link to comment Share on other sites More sharing options...
cruiser54 Posted September 20, 2019 Share Posted September 20, 2019 On 9/18/2019 at 5:33 PM, DJHeath said: Hi, cruiser54. 89 cherokee crank, no start condition, replaced cps (.5vac), refreshed grounds, tried new ecu, replaced cap, rotor, coil. Checked all sensors. I had a spark from coil to cap than from cap to plugs. Have sprayed starter fluid and still no start. I believe I'm not getting fuel injector pulse. Was driving fine. Coming home one day it just died. Would crank but no start. Test for pulse on any colored wire on any injector plug. Wiggle wires near the back of valve cover while cranking. Those wires were prone to abrasion. Link to comment Share on other sites More sharing options...
DJHeath Posted September 21, 2019 Share Posted September 21, 2019 I'm getting .2 vdc from injectors while cranking I wiggled the harness behind the valve cover and no difference. Link to comment Share on other sites More sharing options...
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