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Discussion Starter · #1 ·
Hi,
What could be the reason for this
104183

so in January this happened and lucky it was just a top end rebuild (bent a valve)
Put it all back together, all was fine till the other week. Car kept going to to limp mode when driving hard.

so now this has happened, same cylinder. Cylinder 1
104186

first plugs i had in it was BKR6EG and then went to BKR7EQ
 

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Hi Scott, sorry to see you’re experiencing problems!

If you put up some details on your engine mods/tuning then it may help people to give a more informed diagnosis. 👍🏽
 

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Seems that the symptom has been treated rather than the cause.

Your plug looks like it has been over heated. I would check the others.

Looking online points towards low quality fuel. I would always use 97 RON (super unleaded).

Does you car have a reduced pulley on the charger? I would expect it does. If so always run on super unleaded and be wary that unless it has been properly mapped it will be running lean over 4000 RPM.
 

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Discussion Starter · #6 ·
Thank for the feed back

So first picture. I had on the car
17% pulley.
Top mount airtec intercooler.
Ramair induction kit.
Fletcher radiator.

Then when it blow up. I thought whilst its in pieces I’d put a Newman camshaft 272/400 ph3/4.
4 x Genuine Bosch 550cc Injectors - 0280158117.
And had a guy come and map it. Has been fine for about two months then it’s started playing up and yesterday discovered the plug in the second picture. Other three plugs are all good still.
when read code i kept saying map sensor and misfire cylinder two
 

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this would be better linked to your other thread really, it's very likely related,

It's worth getting an endoscope in the cylinder to see if there are similar signs of damage on the piston,

setting potential for other faults aside, if these are run hard on small pulleys with no map it can lead here, if your map is a generic type flash then it could make this likelihood even worse imo, I had such a file myself and it was opened up to see the tables and we could see in comparison to stock and custom that they'd actually added timing when the mods dictated it needed removing, similarly with fuel elsewhere. These tune types are intended for stock vehicles really I think, where these small changes might give the few HP or TQ increases often claimed.

on cars like yours they're quite possibly incompatible. Maybe yours is different if they've scaled injectors for you, maybe they've altered timing also as a custom tune might, but who's to say they've done it right? To me this resembles other stuff I've seen which can be tune related, familiarity with the model I think counts for a lot, if they came to you it wasn't even tuned on the rollers which is as useful as an ashtray on a motorbike, how can they or you possibly know anything is right under load.

sure there can be other factors but melted plugs or pistons on these will always bring me to the map type if done at all, along with mods in play, which is where you're at I suspect.
 

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are you also on a stock exhaust manifold?
 

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If youre certain the other 3 plugs are as should be, it suggests an individual problem rather than the map or map sensor.

Injector harness could be faulty, again if you know the injectors are as should be.

As CoB says you need to look in the cylinder really first.
 

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1 plug/cylinder can fail before others, Google most similar failures in any car and you'll consistently rear "cylinder xx failure...."

As others have said it's time to find the cause, my bet is the mapping, to map my car with a cam and pulley etc the original map data file needed to be purchased, adjusting the original map to suit will not suffice.

Adding bigger injectors is a "cheat" to increase open loop fueling, where the car will be lean, but it's a gamble not a science.

To clear up any myth....THESE CARS DO NOT SELF ADJUST TO INCREASES IN BOOST, INTAKE AIR (cam as well as boost), FUELING AND OR TIMING.
 
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