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Just finished head gaskets and much more, now occasional misfire on 4 and 8

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  #1  
Old 06-14-2018, 07:08 AM
Roby466's Avatar
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Default Just finished head gaskets and much more, now occasional misfire on 4 and 8

Hi,
If you saw my other thread, I just finished doing the head gaskets on my 2004 D2.
There was coolant traces in cylinders 5 and 7, and definitely corresponding traces on the head gasket. The top bolt between 5 and 7 and 4 and 6 also showed that combustion gasses were escaping in those head bolt holes and corroded the bottom of them.
Now it's all back together but if I look at the misfire counter on the Nanocom, when hot the count goes up on cylinders 4 and 8.
4 has gone up to 6 at the most before the ECM resets the counter
8 has gone to 4 at the most.
Engine runs between 96C and 104C (204F-219F), normally hanging around 98 (208).
It does not happen every time I drive and only at idle.
Would that be two coils packs starting to degrade (pulling the intake another time... (:
Maybe I damaged the wires by trying to clip them back in the original wire holders on the rocker covers...
Is that amount of misfire ''normal'' or should I say frequent with that old of a truck (130000 miles)?
Thanks for any help or advice!
Cheers
David




Here is what was done:
-head gaskets
-all timing cover stuff
-spark plugs (NJK)
-wires were replaced a year ago with magnetor 8mm
-injectors
-air filter
-camshaft
-lifters
-push rods
-heads were resurfaced and valves cleaned and tested
-valve seals replaced
-every gasket that needed replacement in the process.
 
  #2  
Old 06-14-2018, 08:38 AM
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Do a Co2 test throught the coolant tank.
To make sure you don't have a crack in the block behind a cylinder sleeve.
It is possible, but unlikely for both coils to fail at the same time.
 
  #3  
Old 06-14-2018, 02:08 PM
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I would doubt the cracked block because there was no coolant leak in cylinders on that bank of the engine before the head gasket work. There are no bubbles in the coolant and it doesn't pressurise itself prematurely.

I think the problem is SOLVED! read below

Well you know the Nanocom Diagnostic manual says if you change or alter any of the following you must do the ''reset adaptative values''. The list is I think: fuel injectors, ignition, intake, valve train, fuel rail, MAF, etc...
So I changed a bunch of that during the work described above and hadn't done the reset.
I just did it this afternoon and as soon as I hit ok on the Nanocom with the engine idling, there was a slight stumble and then... purring like a kitten!!! What a difference! I guess I'm good now, no other misfire since! It must have been compensating for something in the past, which it no longer needs to now
It's surprising that this reset makes such a difference. I only have 170km since the job.
 
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  #4  
Old 06-14-2018, 07:36 PM
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That makes sense.
Great to hear that!
 
  #5  
Old 06-15-2018, 04:42 AM
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Oh yeah I’m glad (but also surprised) that’s all it is! I was getting ready to pull the plugs and try to look for the steam clean of the cylinder!
Cheers
David
 
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