Vehicle make/model = 2004 Pontiac Grand Prix
Mileage = 36,000
Engine size = 3.4 L
work done prior = Vehicle had a 50:50 mix of Diesel Gas put into it
when it already had some gas in the tank.  The car ran approximately 18km
when it lost power and started making noises.
work done to repair = All spark plugs had been smashed and had bits of
melted aluminum on the porceline. Crown on one piston was broke off.
Piston rings damaged.
tip/donation yes
tech = KK
question = Hello, this vehicle did not have any previous problems until
this fuel was put in.  The mechanic that looked at the car said that
bad fuel would not cause engine damage.  That the damage had to be
caused by something else. Would diesel mixed in the gas and ran through the
system cause severe engine damage. What kind of damage could that be?
What do we look for?






KK:
Thank you for the tip/donation.
The answer is YES. A diesel/gas mix can cause this engine damage. Diesel and gas
obviously have very different properties. They burn in a completely different way.
While driving, the unburned fuel in the cylinders was probably pooling up in the
cylinders. A gas engine cannot run on liguid fuel. A cylinder that begins to fill with
liguid will cause that cylinders pressure to go sky high since there is less area for air,
the cylinder walls will have the oil washed off. The cylinders will be very unbalanced as
it is running. the shear compression of a liquid will cause spark plug and piston
damage. Flakes of material on all plugs is because the piston(s) were starting to come
apart, and metal was being transfered thoughout the engine. The computer was trying
to conpensate for the strange readings on the oqygen sensors, injector pulse would
be changed, timing would be changed, and the engine would go into an unstopable
failure. With such an difference in cylinder pressures, the timing chain may have
jumped/broke, and caused the pistons to hit all the plugs. Although as stated above,
the extreme pressures in the cylinders is enough to do that, and to break a piston.
While driving this way, there were VERY violent things happening in the cylinders.
Cylinder temperatures would be different from cylinder to cylinder, etc. The engine
should be replaced, all the injectors replaced, fuel pump repaced, fuel tank, lines, fuel
rail cleaned out, fuel filter replaced, oxygen sensors replaced, catalytic converter
checked for damage.
If you need any more help, just let me know.
Thanks again for tip/donation.  KK

                                                    
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