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Intermittent misfiring on rb25det

Poketmony33
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Poketmony33 Rookie

Poketmony33

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Intermittent misfiring on rb25det

My r33 skyline has recently started intermittently  misfiring on idle and while driving. 

Spark plugs are new, new yellow jacket coil packs, replaced the o2 sensor, and cleaned the maf several times and a fuel system flush has been performed 

the misfire doesn't sound to be on anyone cylinder. when it does misfire white smoke comes from the exhaust and the coolant level has been going down.

Could the turbo be leaking coolant into the intake causing the misfire when it reaches the cylinder? Has this been an issue before? 

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https://www.sau.com.au/forums/topic/470940-intermittent-misfiring-on-rb25det/
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GTSBoy Grand Master

GTSBoy

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Turbo coolant leak is almost completely unheard of in the real world.  Nor would it cause a misfire unless it was allowing buckets of water to leak.

You will almost certainly have a BHG or a crack in the head, with BHG being top of the list, when it comes to explaining mysterious coolant loss.  The miss may or may not be associated.

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MJTru Mentor

MJTru

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I agree with above. I first had this same problem when I got a used engine. On mine the head was rotten to the point it would leak coolant into the combustion chamber. Hence the white smoke. BHG or bad head.

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Poketmony33 Rookie

Poketmony33

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The previous owner had it sitting in a shed for a while so that could have rooted the head gasket, maybe due to bad coolant (was very murky when I flushed it). But it was driving perfect till a couple of weeks ago 

Kinkstaah Grand Master

Kinkstaah

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Could be worse, I had this issue due to a cracked block.... three times.

:P

But yes, coolant going into the wrong places can cause a misfire. Especially a misfire with white smoke.

Poketmony33 Rookie

Poketmony33

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4 hours ago, GTSBoy said:

But on the scale of likelihood.........0.00000001 chance that it's that.

Still a chance though ?‍♂️?

just the symptoms of a bad intake gasket match to what is happening to my car, like missfires, no power/rough acceleration and coolant going down 

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