Dzimm Posted January 24, 2017 Share Posted January 24, 2017 OK so I am having a no start issue with my DD and I am hoping to get some other opinions so I can get it back on the road ASAP! So I have a 98 XJ with the 4.0 and it won't start. I drove it to work this morning and the CEL was on (usually isnt). Drove fine, no issues whatsoever. Got off work and it turns over just fine sounds like a healthy start but it just won't start. I checked my code and it's the lower O2 sensor, which I replaced recently and is known to be good. I checked for fuel and that's good at the fuel rail, I am getting air out of the spark plug holes while turning over so compression/air seems good without using a proper testing device, I checked for spark and nothing. I read that on the white wire going into the ignition coil I should get a 12v constant when the key is in the "on" position but I am not getting anything. When I put the test light on the green wire I get voltage in pulses when the engine is turning over. I pulled the plug wire from the output side of the coil and it was a little corroded and rusty so I cleaned it up but still no spark. I also tried a spare Stator I had but that made no difference. From what I can gather with the O2 sensor tripping the CEL, I'm guessing I'm not burning all my fuel and it probably needs a tune up. I'm doing the plugs, wires, etc. Including the coil tomorrow morning. However I'm confused as to how it was totally normal all the way to work and as soon as it was shut off it wouldn't start. I'm really hoping it's not the crankshaft sensor but it is a possibility. I also read that it could be caused by a bad PCM, I do have an extra but my XJ is a 2dr SE with no options, would a PCM from a 98 4dr sport with the same engine/Trans but all the other options work? Is there anything else that anyone can think of to check? Other maybe helpful info, the battery has a good 12.3 volts and everything else on the Jeep is working fine. Thanks in advance. Link to comment Share on other sites More sharing options...
sinkrun Posted January 24, 2017 Share Posted January 24, 2017 Crank sensor they do not always throw codes and can do some odd stuff also all the grounds need checked. Link to comment Share on other sites More sharing options...
Dzimm Posted January 24, 2017 Author Share Posted January 24, 2017 Crank sensor they do not always throw codes and can do some odd stuff also all the grounds need checked. Ah yes thats the other thing I was trying to think of, the grounds are good. And yeah thats what I was afraid of. Are the cheaper ebay crank sensors any good. I really don't want to fork over $100+ for it and the $15 ones have a much more appealing price tag. Link to comment Share on other sites More sharing options...
Hippie66 Posted January 24, 2017 Share Posted January 24, 2017 Have someone crank it while you wiggle the harness at the PCM. If it starts, cracked circuit board inside the PCM. Link to comment Share on other sites More sharing options...
Automan2164 Posted January 24, 2017 Share Posted January 24, 2017 Crank sensor. Pay attention to if the tachometer is moving also when cranking. Rob Link to comment Share on other sites More sharing options...
shelbyluvv Posted January 24, 2017 Share Posted January 24, 2017 Unplug the CPS and spit in the plug then reconnect it. It actually works most of the time. Make sure the key is on and Listen for the relays to click in the PDC. My 97 converted MJ used to do the same thing. If yours starts get to NAPA and buy a CPS. Link to comment Share on other sites More sharing options...
sinkrun Posted January 24, 2017 Share Posted January 24, 2017 Advance auto parts has a coupon code online for $40.00 of $100.00 I just bought one this weekend and used the code. Had to buy a few dollars worth of towels to get to the $100.00 mark. Used the code got the sensor for $65.00. I would really like to order a mopar off ebay for $85.00 but could not wait . You could pull one from your parts rig?? if it works then order the mopar later. Link to comment Share on other sites More sharing options...
Dzimm Posted January 24, 2017 Author Share Posted January 24, 2017 Advance auto parts has a coupon code online for $40.00 of $100.00 I just bought one this weekend and used the code. Had to buy a few dollars worth of towels to get to the $100.00 mark. Used the code got the sensor for $65.00. I would really like to order a mopar off ebay for $85.00 but could not wait . You could pull one from your parts rig?? if it works then order the mopar later. Thanks I may go that route. I could pull it from the truck but idk for sure that one works nor do I want to do it twice if I don't have to. Link to comment Share on other sites More sharing options...
Dzimm Posted January 25, 2017 Author Share Posted January 25, 2017 Well the tune up and ignition coil didn't fix my starting issue but the coil was cracked and falling apart so it definitely needed replaced. I went and bought a crankshaft position sensor so I will try it tomorrow, and of course it is now cold and snowing... Great. Link to comment Share on other sites More sharing options...
Dzimm Posted January 25, 2017 Author Share Posted January 25, 2017 Still won't start after the new CPS and the other PCM didn't work either. I'm at a loss right now. Link to comment Share on other sites More sharing options...
HOrnbrod Posted January 25, 2017 Share Posted January 25, 2017 If you haven't already, open up the distributor and check the cap and rotor, coil wire, and see if sync sensor wires exiting the distributor under the cap not pinched off. I had a no-start condition caused by a bad sync sensor once, and it didn't how up as a fault code. Link to comment Share on other sites More sharing options...
Dzimm Posted January 25, 2017 Author Share Posted January 25, 2017 Crank sensor. Pay attention to if the tachometer is moving also when cranking. Rob Tach is not moving when cranking. Does the starter even spin fast enough for that to show up on the tach? If you haven't already, open up the distributor and check the cap and rotor, coil wire, and see if sync sensor wires exiting the distributor under the cap not pinched off. I had a no-start condition caused by a bad sync sensor once, and it didn't how up as a fault code. I have had the distributor completely apart and all the wires are fine. It's got a new stator, cap, and rotor on it. I went back and rechecked all my grounds and they are fine as well as swapped the And relay out with another and nothing has changed. Link to comment Share on other sites More sharing options...
HOrnbrod Posted January 25, 2017 Share Posted January 25, 2017 What OBD2 code(s) are showing up? Link to comment Share on other sites More sharing options...
Dzimm Posted January 25, 2017 Author Share Posted January 25, 2017 What OBD2 code(s) are showing up? None. It originally was the lower O2 sensor but it went away likely due to the battery being disconnected so long. I'm not getting any codes now. A guy here at work has a better scan tool that we are gonna try here in a little bit and see if it will pick anything up. Link to comment Share on other sites More sharing options...
Hippie66 Posted January 25, 2017 Share Posted January 25, 2017 You shouldn't need a tool to pull codes. Should be able to get them by cycling the ignition switch. Did that on my '93 XJ and '97 ZJ. Link to comment Share on other sites More sharing options...
Dzimm Posted January 25, 2017 Author Share Posted January 25, 2017 You shouldn't need a tool to pull codes. Should be able to get them by cycling the ignition switch. Did that on my '93 XJ and '97 ZJ. I've tried this in the past and never had success. No matter what versions of the procedure I have used. Link to comment Share on other sites More sharing options...
HOrnbrod Posted January 25, 2017 Share Posted January 25, 2017 You shouldn't need a tool to pull codes. Should be able to get them by cycling the ignition switch. Did that on my '93 XJ and '97 ZJ. For reading OBD2 codes I had to look it up, and you are right. I didn't know the key trick would work on OBD2 vehicles as well as the OBD1 stuff - thanks. It's always good when you learn something new. :cheers: Link to comment Share on other sites More sharing options...
Hippie66 Posted January 25, 2017 Share Posted January 25, 2017 It's never failed me, as long as the switch is cycled exactly as specified. Link to comment Share on other sites More sharing options...
Dzimm Posted January 25, 2017 Author Share Posted January 25, 2017 Well his scanner says camshaft sensor. I've tried 2 and neither worked so I'll go get another and try that. Also to clarify, is the white wire going into the ignition coil supposed to have a 12v constant? I read that somewhere it does but I can't find any info on it in the FSM or online. Link to comment Share on other sites More sharing options...
HOrnbrod Posted January 25, 2017 Share Posted January 25, 2017 Well his scanner says camshaft sensor. I've tried 2 and neither worked so I'll go get another and try that. No, you replaced the crankshaft position sensor (CPS) on the bell housing, not the cam sensor. The cam sensor is in the distributor and it's sometimes called the distributor pickup or sync sensor like I mentioned previously. I had one go bad in my 91 causing the same no-start symptoms you have and it didn't throw a code. The earlier (96 and below) cam sensors look like the below, but am not sure about the 98's. It may be under the distributor for these vehicles and needs to be indexed. Link to comment Share on other sites More sharing options...
Dzimm Posted January 25, 2017 Author Share Posted January 25, 2017 Well his scanner says camshaft sensor. I've tried 2 and neither worked so I'll go get another and try that. No, you replaced the crankshaft position sensor (CPS) on the bell housing, not the cam sensor. The cam sensor is in the distributor and it's sometimes called the distributor pickup or sync sensor like I mentioned previously. I had one go bad in my 91 causing the same no-start symptoms you have and it didn't throw a code. The earlier (96 and below) cam sensors look like the below, but am not sure about the 98's. It may be under the distributor for these vehicles. I replaced both the stator (cam sensor) and the crank sensor. The stator I wasn't sure if it worked for sure because it came off my Comanche and I haven't had that motor running yet. Link to comment Share on other sites More sharing options...
HOrnbrod Posted January 25, 2017 Share Posted January 25, 2017 Get a new Mopar unit and it should start. The aftermarket cam sensors are 50-50. Did the cam sensor you replaced look like the one in my pic? And what was the P-code from the scanner? P0336 is a problem with the Crankshaft Position Sensor and P0341 is a problem with the Camshaft Position Sensor. Link to comment Share on other sites More sharing options...
Hippie66 Posted January 25, 2017 Share Posted January 25, 2017 Well his scanner says camshaft sensor. I've tried 2 and neither worked so I'll go get another and try that. No, you replaced the crankshaft position sensor (CPS) on the bell housing, not the cam sensor. The cam sensor is in the distributor and it's sometimes called the distributor pickup or sync sensor like I mentioned previously. I had one go bad in my 91 causing the same no-start symptoms you have and it didn't throw a code. The earlier (96 and below) cam sensors look like the below, but am not sure about the 98's. It may be under the distributor for these vehicles and needs to be indexed. I've had the wires break where they enter the distributor. You couldn't see it, but wiggling the wires while someone cranks the engine over would let it start. Link to comment Share on other sites More sharing options...
Dzimm Posted January 25, 2017 Author Share Posted January 25, 2017 Get a new Mopar unit and it should start. The aftermarket cam sensors are 50-50. Did the cam sensor you replaced look like the one in my pic? And what was the P-code from the scanner? P0336 is a problem with the Crankshaft Position Sensor and P0341 is a problem with the Camshaft Position Sensor. Yes I replaced with the correct cam sensor that matches your picture, it came from the 98 XJ motor in the manche. Like I said idk if it is any good. And it didn't have an actual number code, my CEL wasn't even on but his scan tool picked it up as a problem and spelled out camshaft position sensor rather than a code. Link to comment Share on other sites More sharing options...
Dzimm Posted January 25, 2017 Author Share Posted January 25, 2017 Well his scanner says camshaft sensor. I've tried 2 and neither worked so I'll go get another and try that.No, you replaced the crankshaft position sensor (CPS) on the bell housing, not the cam sensor. The cam sensor is in the distributor and it's sometimes called the distributor pickup or sync sensor like I mentioned previously. I had one go bad in my 91 causing the same no-start symptoms you have and it didn't throw a code. The earlier (96 and below) cam sensors look like the below, but am not sure about the 98's. It may be under the distributor for these vehicles and needs to be indexed. I've had the wires break where they enter the distributor. You couldn't see it, but wiggling the wires while someone cranks the engine over would let it start. Wiggling the wires isnt working in my case. Link to comment Share on other sites More sharing options...
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