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Xj broke down while traveling

V

Vitzaa

NAXJA Forum User
Location
Los angeles
Hey guys, family and I are currently in glacier Montana and the xj threw a p1391 code and stalled while driving. I replaced the crank position sensor (Mopar unit I carried in the trunk) and cam position sensor on the side of the road. No start. Fuel rail squirts fuel. Sprayed starter fluid in the throttle body and nothing. Couldn't check for spark as it's a 2001 with the coil pack... Fuses are all intact.wiring looks good from what I was able to trace around. Grounds look good from what I could find (battery to body, rear head to body, ground by the dip stick to the harness)

Anyone have any ideas? All the shops are booked out for two weeks here... Got limited tools with me, volt meter, wrenches/sockets, power probe, etc.

Help 😞
 
Vitzaa said:
Hey guys, family and I are currently in glacier Montana and the xj threw a p1391 code and stalled while driving. I replaced the crank position sensor (Mopar unit I carried in the trunk) and cam position sensor on the side of the road. No start. Fuel rail squirts fuel, fuel pump is new and primes. Sprayed starter fluid in the throttle body and nothing. Timing chain and gears are new. Couldn't check for spark as it's a 2001 with the coil pack... Fuses are all intact.wiring looks good from what I was able to trace around. Grounds look good from what I could find (battery to body, rear head to body, ground by the dip stick to the harness).

I'm hoping it's not the ecu. I got it used. Jeep was an auto that I had converted to a Novak ax15, was a major pain in the a$$ to find a 2001 manual ecu

Anyone have any ideas? All the shops are booked out for two weeks here... Got limited tools with me, volt meter, wrenches/sockets, power probe, etc.

Help 😞
Click to expand...
 
When you replaced the cam senor, I assume you just replaced the sensor itself, not the entire unit (oil pump drive that goes into the block)?
 
That is a major bummer.

Are the replacement parts known to be good? Tested good?

How did you check grounds?

It would be nice to know actual fuel pressure, but given your test with starter fluid it certainly sounds like a spark issue.

I would take the grounds apart, clean everything and reassemble (ideally with a conductive grease like Ox-Gard).

I would also carefully follow all the O2 sensor wires and make sure none of those have grounded out, particularly to the exhaust, although I don't know how that particular failure would have thrown that particular code.

You could try unpluggling the ECU and re-connecting it, but that is an unlikely solution.

Beyond that I don't know what else to try without having access to more resources.
 
Anak said:
That is a major bummer.

Are the replacement parts known to be good? Tested good?

How did you check grounds?

It would be nice to know actual fuel pressure, but given your test with starter fluid it certainly sounds like a spark issue.

I would take the grounds apart, clean everything and reassemble (ideally with a conductive grease like Ox-Gard).

I would also carefully follow all the O2 sensor wires and make sure none of those have grounded out, particularly to the exhaust, although I don't know how that particular failure would have thrown that particular code.

You could try unpluggling the ECU and re-connecting it, but that is an unlikely solution.

Beyond that I don't know what else to try without having access to more resources.
Click to expand...

The sensors are new, now sure if they're defective but who knows? Talk about bad luck if they are...
I got the jeep flat towed to the camp site, will clean the grounds and spend some time tracing wiring today. Thank you
 
I sort of thought you needed to 'sync' the cam sensor too. I haven't had to deal with that. I did have a distributor bushing pop out. So, bad distributor.
I did have issues with my 2000 XJ Fed not starting. I replaced probably all the sensors. Then I got a set of NOID lights, just needed one, to check the Injectors. See if they were operating. The NOID light wouldn't flash when cranking. Then it would just flash as I left off the key. Weird. I talked to friend, mainly into Fords and Harleys. Said it might be the ignition switch. It was $50 a NAPA at the time. Installed and a few tries later, it was running. I popped a couple tries though. I did try and purchase another ignition switch at one of the other parts stores on the road. My '98 stalled out and wouldn't start. Theirs was $100. The '98 cooled off and started latter. Didn't stop till I got home.
 
I would also dis-connect the battery to reset the pcm if you haven't done that already.
 
maxbraketorque said:
How about this:

https://www.cherokeeforum.com/f2/p1391-solved-259524/

https://www.jeepforum.com/threads/heat-soak-fix-not-what-you-may-think.2975897/

http://jeep.blackonyx.net/pdfs/jcss.pdf
Click to expand...

Wow, interesting... Thank you for this.

I would think it would start or at least sputter while cranking with the timing being off, mine just cranks without even trying to start. Dunno what could cause the cam timing to fall out of sync but I guess it's definitely a possibility. Will try to check alignment today. Thanks again!
 
75SV1 said:
I sort of thought you needed to 'sync' the cam sensor too. I haven't had to deal with that. I did have a distributor bushing pop out. So, bad distributor.
I did have issues with my 2000 XJ Fed not starting. I replaced probably all the sensors. Then I got a set of NOID lights, just needed one, to check the Injectors. See if they were operating. The NOID light wouldn't flash when cranking. Then it would just flash as I left off the key. Weird. I talked to friend, mainly into Fords and Harleys. Said it might be the ignition switch. It was $50 a NAPA at the time. Installed and a few tries later, it was running. I popped a couple tries though. I did try and purchase another ignition switch at one of the other parts stores on the road. My '98 stalled out and wouldn't start. Theirs was $100. The '98 cooled off and started latter. Didn't stop till I got home.
Click to expand...

Interesting. Will check this as well today. Hopefully I'll be able to find one in stock around here
 
how did you check to see if your injectors are firing? can you see the rpm gauge move a little bit when cranking? im not 100% sure but you might be able to unplug the cam sensor and try starting it. the early models would run with out it but would "guess" what cylinder to fire during cranking.
 
tech1001 said:
I would take the cam sensor back off and check to see if it turning inside when you crank it
Click to expand...


Bingo! You nailed it...

After messing with the wiring, fuse box, and fuses 21 and 18 not getting power... Jumping terminals on the asd relay powers the fuses. Relay clicks but doesn't power the fuses. Blah blah blah. Figured I'd do as you suggested and the dwell flange rotator cup thing does NOT spin when cranking... I'll link a video.

Now to find a replacement:loveu:
 
That sucks because now you have to find out what broke and WHY!
 
What does the cam gear look like?
 
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