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Miss fire 4 and 8. HELP leaving on a trip soon

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Old 07-03-2011, 03:43 AM
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Exclamation Miss fire 4 and 8. HELP leaving on a trip soon

I NEED HELP. I am leaving on a trip and I am beyond confused. I have codes come up 1300 304 & 308. I have so far changed the wires(sti), spark plugs(denso iridium), ran a fuel dinrail injector cleaner, replaced the the head gasket and new fuel pump. We measured the resistance in the coil and it seems ok. I have not changed any of the coils or injectors. I have been dealing with this for months and can get no consistency. I can go 200+ miles with no codes and then it appears. It is amazing after doing all these things I have lots of power and can't even tell when it missfires other than the code. The odd thing is the history of the codes are misfire in 4 and 6 then it was just 4 and now it is 4 and 8. It seems to me this could be a camshaft sensor, coil or injector or maybe an O2 sensor. The valves were replaced with the head gasket. I have brought this to at least some of the highest rated mechanics in Portland OR but no avail. Should I just replace these items or BLOW IT UP and call it good.
 
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Old 07-03-2011, 07:10 AM
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Replace the crank shaft position sensor.
There is a write up on how to do it on the top of the page.
 
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Old 07-03-2011, 08:20 AM
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Spike, the crank sensor has nothing to do with a misfire, it is a hot start sensor only with no grey area.

As for the actual issue, how many miles on the truck? I would consider doing a compression test if this is a high miler truck, run a can of 44K thru the tank and keep an eye on the coil as a possible problem.
 
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Old 07-03-2011, 10:42 AM
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Originally Posted by Disco Mike
Spike, the crank sensor has nothing to do with a misfire, it is a hot start sensor only with no grey area.
Actually it can Mike, we have had several people on here with a random mis fire that was cured with a new crank sensor.
It is a cheap and easy thing to rule out since his plugs and wires are all new.
Remember that the crank sensor controls spark and while the #1 symptom is a stalling when hot or a no start when hot it can also send weird spark signals.
 
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Old 07-03-2011, 02:14 PM
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Thanks for both of your inputs. To clarify the car has 109000 on it. The problem is the issue is not consistent. I can not get the car to repeat the code. I will do a compression test to verify but I was wondering if being on the same bank would have anything to do with it and that is why I was wondering if it could be an O2 sensor. Where is the link for the camshaft sensor. I have replaced so many parts already another one won't hurt.
 
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Old 07-03-2011, 05:11 PM
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A bad O2 will not cause a mis fire code.
In the write up section on the top of the DII page is a write up on how to replace the crank shaft sensor NOT the cam sensor.
The crank sensor is about $60 at AutoZone, the cam sensor is about $300.
Replace that one if you want to but I wouldnt, I would replace the crank sensor.

https://landroverforums.com/forum/di...t-reads-26352/
 
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Old 07-03-2011, 06:24 PM
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Thanks. I did mean crankshaft. It looks pretty simple and it looks like other people had have some pretty good luck not using the T5
 
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Old 07-03-2011, 06:46 PM
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Originally Posted by Spike555
Actually it can Mike, we have had several people on here with a random mis fire that was cured with a new crank sensor.
It is a cheap and easy thing to rule out since his plugs and wires are all new.
Remember that the crank sensor controls spark and while the #1 symptom is a stalling when hot or a no start when hot it can also send weird spark signals.
Those people were completley wrong.
Think about it, all the crank sensor does is send a signal to the ECU that then fires the coils and fuel pump. It can not in any way be selective and cause a misfire, trust me on this, I am not wrong.
 
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Old 07-03-2011, 07:48 PM
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Straight from rave:

"It is vital that the correct air gap is maintained, if the air gap becomes too wide the CKP signal becomes too weak, causing possible engine misfires to occur."

I would think that a bad crank sensor might have too weak of a signal, and have symptoms similar to an air gap that is too large.

Here are the symptoms from RAVE about a failing sensor:

"In the event of a CKP sensor signal failure any of the following symptoms may be observed:
l Engine cranks but fails to start.
l MIL remains on at all times.
l Engine misfires (CKP sensor incorrectly fitted).
l Engine runs roughly or even stalls (CKP sensor incorrectly fitted).
l Tachometer fails to work.
l Flywheel adaption reset – ferrous contamination"
 
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Old 07-04-2011, 12:17 AM
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You stated that the heads were rebuilt. Were the exhaust guides replaced or trimmed?
 


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