melted pistons

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12psi Protege5
Today, changing the plugs i noticed 1 plugs was full of some micro-specs of "something". So I believe thats aluminum melted on them, specially 1 of them.

I look into the chamber with a light and BANG! for my surprise, I see a nice crater in the center of the piston around 2 centimeters wide, its still not through the piston, but Im sure there more damage hidden because I can smell the oil burning while riding around but no smoke.

I would like to take pictures of the piston but the camera cant take them.

But the car is still running strong...

...still waiting for my forged goodies....

here are the pics, first plugs shows the debrees melted on it, second plug is a brand new plug pulled after a few 6-7psi runs, looks like its running lean with the FMU!

BKR6E plugs
 

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this is the best I could do for pictures of the piston!
 

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hmm...running lean, the plug is too hot...

I may need to run 7 heat range, im touching 13-14psi on stock internals
 
KzA said:
how exactly does that happen..damn

get those forged internals
Leaning out will cause the exaust temperature to shoot up and that heat will oxidize the piston.
 
What EGT's have you been seeing? Lean is Lean, even if it's forged or not, it will still do damage. Do you have xtra injectors on there to give you the added fuel you need?
 
Bigg Tim said:
What EGT's have you been seeing? Lean is Lean, even if it's forged or not, it will still do damage. Do you have xtra injectors on there to give you the added fuel you need?
Normal EGTs except that sometimes it would go a bit higher and jumpy.

problem was...that I run 4 extra injectors and while running 12psi one day i notice the ping, a lot of ping so I just push a bit the throttle and notice that no extra fuel is being injected, I pull over and saw a blown fuse on the extra injectors wiring...and for my surprise, THAT PARTICULAR CYLINDER, the extra injector plug was broken, wires out of the plugs!!!

So I was only adding fuel to 3 cylinders for an unknown period of time!!!

Only that cylinder has the crater!

Now Im running FMU, that thing is crap, but works, I may keep it even forged, adding a bit of pressure to the fuel system will help the stock injectors and extra injectors, no big numbers on the map.
 
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igdrasil said:
Normal EGTs except that sometimes it would go a bit higher and jumpy.

problem was...that I run 4 extra injectors and while running 12psi one day i notice the ping, a lot of ping so I just push a bit the throttle and notice that no extra fuel is being injected, I pull over and saw a blown fuse on the extra injectors wiring...and for my surprise, THAT PARTICULAR CYLINDER, the extra injector plug was broken, wires out of the plugs!!!

So I was only adding fuel to 3 cylinders for an unknown period of time!!!

Only that cylinder has the crater!

Now Im running FMU, that thing is crap, but works, I may keep it even forged, adding a bit of pressure to the fuel system will help the stock injectors and extra injectors, no big numbers on the map.
I sometimes worry about my EIC-2 crapping out at WOT and killing the motor, it has never happend and probably never will, just a risk I guess.
 
Yeah, you will know if it takes a s***, it will go lean, but what when 1 out of 4 injectors are out and you see good A/F numbers because all 3 are pig rich and the one lean levels out the mixture that the O2 sensor reads?
 
igdrasil said:
Yeah, you will know if it takes a s***, it will go lean, but what when 1 out of 4 injectors are out and you see good A/F numbers because all 3 are pig rich and the one lean levels out the mixture that the O2 sensor reads?
Agreed, It suchs because it's not like you can get a flashlight and look in there as the car is running.

(dark)​
 
is your fuel management a stand alone or piggy back?

wouldn't the stock ecu have notice something like "cyl3 running lean" or "cyl3 misfire"

or some fancy snapon scanner mumbo jumbo...

i'm just curious cause my cel just came on... but i think it's from the egr (i didn't plug it... just left it open) gotta put the scanner to it this weekend.

-pedro
 

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