2001 Fozzt knockin

scoobiesforlife

scoobiesforlife

New member
my mothers got a 2001 Fozzy, its knocking no matter what we have done, we have replaced the knock sensor, ran a fuel system cleaner as well as it had the correct heat range for plugs in it (ngk platinums, heat range of 6. oem requirement) what else could be causing the motor to still knock?

we have also noticed that it doesn't do it with the high octane, does a little bit with the mid grade, and knocks like a sunnova gun with the regular.

any insight would be helpful

 
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intake leak after the maf? i mean, if it's a big leak, will make it really lean, it could cause the knocking....

 
at drvsdvw: not sure, will look tomorrow

at kblood477: we have since replaced the plugs with the correct ones (ones in it had a heat index of 4, and oem are an index of 6) and like i said the knock sensor has been changed

 
what kind of "knocking" are we talking about here.....valve tick or engine failure knock...detonation knock? your saying the only thing that makes it better is the grade of fuel?

 
pre-ignition. Ping. Crackling sound while a trying to accelerate.

things that cause pre-ignition:

*carbon build up on the piston tops

*spark plugs

*bad plug wires <--once had a 5.0L pinging because the plug wires on paired firing order cylinders were cross firing. I separated the wires and gained 10hp and no more ping.

*incorrect timing

*leaking injector(s)

*too much compression

*vacuum leaks

hope this helps

 
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Are you sure it's spark knock and not the typical high mileage 2.5 N/A piston slap issue? Does the sound get worse as you accelerate harder/give it more gas? Or does it quiet down a bit under heavier acceleration and makes more noise under light acceleration?

 
it gets worse as the accelerator gets heavier, my dad has rebuilt motors and everything, so between him and myself it is spark knock.

my car is a different story, i got the typical 2.5 n/a dohc bottom end knock but that's a different story like i said

 
My first thought is carbon buildup if no certain air leaks knock sensor or fuel filter type issues. Try running an injector cleaner? Not that I believe in that but I work on vw's and see wynns stuff work on them.

 
alrighty...time to do research and price this stuff out
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It wouldn't surprise me at all if it wasn't just 2.5 piston slap. Most of them do it, and it can sound like many things

 
inski said:
Wynn's fuel injection system service or top engine service will kick that carbon's butt.
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Inski, of what r u speaking here? is it one of those 'tuneup in a can' kinda things or is it a prescribed service plan licenzed by Wynn's or what?

Inquiring minds (esp those with r-r-r-rappy 2.5 motors) want to know!

 
Wynn's special sauce.

We eliminate fuel going into engine.

Hook up the 16oz. pressurized can of special sauce, looks like fuel, smells horrid.

Run the engine on the Wynns stuff alone, thru the rails and injectors with higher than normal pressure to knock out any debris from system but also to get some extra onto the combustion chamber to loosen any carbon build up from piston tops and and valve faces. Everyone who gets a 30k, 60k, 90k, or 120K service gets this done.

After its all done the engine will ping a lot, a whole lot. This is due to the loose carbon in the combustion area being saturated with Wynns and fuel. But its loose carbon, and about 10 minutes of driving its all knocked loose and blown out the exhaust. It must be done immediately after the Wynns treatment so the carbon doesn't get a chance to harden back up.

Now you have squeaky clean injectors AND a sparkling combustion area. Some cars ( inline 4s and nasty GMs cough cough ) need the application twice.

 
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