P0306 Will not stop!
02-03-2013, 08:40 AM
#46
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Year: 1998
Model: Cherokee
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02-11-2013, 11:10 AM
#48
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Year: 2000
Model: Cherokee
Engine: 4.0
More updates.
Well I have the Re-manufactured PCM from Florida with a LIFETIME guarantee. Haven't had a chance to install it yet. Crappy weather and no garage.
Will see if I have a chance this afternoon before it turns cold again.
Still showing the CEL.
I did replace the throttle body from my 99 I have for parts. Apparently the PO had replaced all the sensors on it at some time in the recent past. All looked like the just came out of the box.
Still idling rough and still missing.
Will see if I have a chance this afternoon before it turns cold again.
Still showing the CEL.
I did replace the throttle body from my 99 I have for parts. Apparently the PO had replaced all the sensors on it at some time in the recent past. All looked like the just came out of the box.
Still idling rough and still missing.
02-11-2013, 02:42 PM
#49
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Another update. Long one!!!
Well since noon I've been able to remove and replace the PCMs, Remove and clean the Valve cover and replace the gasket with a new Felpro one.
While it was off and the plugs were out I had my wife turn the engine over while I examined the valve train. Looks real good. No sludge in top end and no evidence of a head crack anywhere on head. The lifters seemed to pump up the same height across the board and the push rods all were doing the spin correctly. No evidence of a spring problem on Number six. I was going to do a compression test but for the life of me I couldn't get my tester to thread into the spark plug holes.
It's a cheappy POS and I had only used it on the 18MM plugs previously. You're supposed to take off the adapter and it will thread into the 14mm plug hole....NOT, so I can't tell you what the compression is. I'll work on that.
I can tell you that all the plugs after 9,000 kilometres look excellent. They all have a bone color to the porcelin. It was text book color for the proper fuel mix. No sign of any oil burning.
I also have one of those inspection cameras that use fibre optics.
I looked into all the plug holes and found a nice tan color on all the piston tops. no sign of carbon build up.
If I was guessing and didn't know the actual milage I'd say this only had maybe 50 or 60K miles on it.
Buttoned it all back up and took it for a little spin.
It idles at about 650 to 700 RPM in or out of drive.
It still feels like a bit of a miss going on at 1100 RPM also.
CEL is currently off.
If it comes back I'm going to take the throttle body off and try to look at #6 through the intake manifold but I'm still pretty sure it'll be OK.
My next option is to start taking the wiring harnes apart to look for a broken wire. Not looking forward to that!
I have a question about that maybe some of the more experienced mechanics can answer for me. From what I've read and seen myself is if you unplug #6 injector while the vehicle is running you'll get a P0206 code. To my way of thinking this would also simulate a broken wire correct? So then how is the computer finding a miss to throw a P0306 code?
I never get a P0206 unless I unplug the injector and it ONLY shows P0306. The computer fires #1 and #6 at the same time on the coil pack.
I'm missing something here aren't I?
While it was off and the plugs were out I had my wife turn the engine over while I examined the valve train. Looks real good. No sludge in top end and no evidence of a head crack anywhere on head. The lifters seemed to pump up the same height across the board and the push rods all were doing the spin correctly. No evidence of a spring problem on Number six. I was going to do a compression test but for the life of me I couldn't get my tester to thread into the spark plug holes.
It's a cheappy POS and I had only used it on the 18MM plugs previously. You're supposed to take off the adapter and it will thread into the 14mm plug hole....NOT, so I can't tell you what the compression is. I'll work on that.I can tell you that all the plugs after 9,000 kilometres look excellent. They all have a bone color to the porcelin. It was text book color for the proper fuel mix. No sign of any oil burning.
I also have one of those inspection cameras that use fibre optics.
I looked into all the plug holes and found a nice tan color on all the piston tops. no sign of carbon build up.
If I was guessing and didn't know the actual milage I'd say this only had maybe 50 or 60K miles on it.
Buttoned it all back up and took it for a little spin.
It idles at about 650 to 700 RPM in or out of drive.
It still feels like a bit of a miss going on at 1100 RPM also.
CEL is currently off.
If it comes back I'm going to take the throttle body off and try to look at #6 through the intake manifold but I'm still pretty sure it'll be OK.
My next option is to start taking the wiring harnes apart to look for a broken wire. Not looking forward to that!
I have a question about that maybe some of the more experienced mechanics can answer for me. From what I've read and seen myself is if you unplug #6 injector while the vehicle is running you'll get a P0206 code. To my way of thinking this would also simulate a broken wire correct? So then how is the computer finding a miss to throw a P0306 code?
I never get a P0206 unless I unplug the injector and it ONLY shows P0306. The computer fires #1 and #6 at the same time on the coil pack.
I'm missing something here aren't I?
02-12-2013, 09:12 AM
#50
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Year: 1993
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Just a thought.. I know you replaced the plugs, but what about the wires? They in good shape? You can 'mist' them while it's running to check for leaks. (or just grab onto them) 
02-12-2013, 04:40 PM
#52
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For any of you loyal fans who have been following this thread, I got another update!
Did you know that the 2000 XJ has a rev limiter?
Found that out when I temporarily lost my mind (don't ask my wife, she lies!) and got mad at my missing engine, not missing as in gone but ..... never mind.
Anyways I was trying the water trick again and I held the throttle WIDE OPEN! Thats when I heard it bouncing off the rev limiter.
Cool! Damn near flooded out the engine with about a 1/2 gallon of water.
Idling fine now.
I erased the CEL and I'll let you know tomorrow if it rears it's ugly head again.
Did you know that the 2000 XJ has a rev limiter?
Found that out when I temporarily lost my mind (don't ask my wife, she lies!) and got mad at my missing engine, not missing as in gone but ..... never mind.
Anyways I was trying the water trick again and I held the throttle WIDE OPEN! Thats when I heard it bouncing off the rev limiter.
Cool! Damn near flooded out the engine with about a 1/2 gallon of water.
Idling fine now.
I erased the CEL and I'll let you know tomorrow if it rears it's ugly head again.
Last edited by Jamie57; 02-12-2013 at 04:47 PM. Reason: speling
02-12-2013, 04:48 PM
#53
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Year: 1990
Model: Cherokee (XJ)
Engine: 4.0
For any of you loyal fans who have been following this thread, I got another update!
Did you know that the 2000 XJ has a rev limiter?
Found that out when I temporarily lost my mind (don't ask my wife, she lies!) and got mad at my missing engine, not missing as in gone but ..... never mind.
Anyways I was trying the water trick again and I held the throttle WIDE OPEN! Thats when I heard it bouncing off the rev limiter.
Cool! Damn near flooded out the engine with about a 1/2 gallon of water.
Idling fine now.
I erased the CEL and I'll let you know tomorrow if it rears it's ugly head again.
Did you know that the 2000 XJ has a rev limiter?
Found that out when I temporarily lost my mind (don't ask my wife, she lies!) and got mad at my missing engine, not missing as in gone but ..... never mind.
Anyways I was trying the water trick again and I held the throttle WIDE OPEN! Thats when I heard it bouncing off the rev limiter.
Cool! Damn near flooded out the engine with about a 1/2 gallon of water.
Idling fine now.
I erased the CEL and I'll let you know tomorrow if it rears it's ugly head again.
If that works, we'll have to amend the "water" instructions!!
02-13-2013, 05:40 PM
#56
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Crap it's back. Going to take wiring harness apart tomorrow if I don't get called into work.
And if it's not that then I'll change the valve springs. Can get 4 of them from Crown parts for cheap.
And if it's not that then I'll change the valve springs. Can get 4 of them from Crown parts for cheap.
02-19-2013, 06:31 PM
#59
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02-19-2013, 08:28 PM
#60
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The most important question is how does the computer interperate a miss. I have never been given a reasonable answer.
Does it get its miss info from the signal sent to the coil pack?
Does it get its miss info from the signal sent to the injectors?
There are no miss sensors. There is no knock sensor. I hear it counts misses then registers a code after X amount of misses. A broken valve spring will cause a miss so how is that counted?
If we knew what it counted it would be easier to fix.
Im beginning to think its a load of crap Chrysler planned into the coil pack design.
Ron
Does it get its miss info from the signal sent to the coil pack?
Does it get its miss info from the signal sent to the injectors?
There are no miss sensors. There is no knock sensor. I hear it counts misses then registers a code after X amount of misses. A broken valve spring will cause a miss so how is that counted?
If we knew what it counted it would be easier to fix.
Im beginning to think its a load of crap Chrysler planned into the coil pack design.
Ron