Diagnosing engine knocks...

caballo · Dec 22, 2005

You guys probably remember my engine problem that arose a short time ago. If not here's the cliff notes

spark plug ejects.
no start condition w/ various codes.
replace fuel pump
will not idle
fuel injector wide open.
trip to ford dealer-knock appears. 200.oo bill and no progress.
replace injectors, replace cop's, replace fuel pressure regulator.

NOW car idles and drives but there is a knock.

1) any tips/tricks (oil additives that might make it go away)

or

2) any advice on how to diagnose the knock ie. main vs rod bearing or maybe valvetrain...

Thanks again...:SNSign:

caballo · Dec 22, 2005

caballo · Dec 22, 2005

Then again it might be "piston slap" any help is appreciated...

40th GT · Dec 22, 2005

Piston slaps are supposed to be heard even at idle. One way to find out if a car is knocking or not, is to check the spark plug electrode color. White is a sign of knock.

caballo · Dec 23, 2005

40th GT said:
Piston slaps are supposed to be heard even at idle. One way to find out if a car is knocking or not, is to check the spark plug electrode color. White is a sign of knock.

I meant like rod bearing or main bearing knock. It's almost quiet at idle, but you can definitely tell when driving. It's not louder(well, maybe a little) it just gets faster...

caballo · Dec 23, 2005

BUMP...again

tomustang · Dec 23, 2005

is it like a clank-clank-clank?

caballo · Dec 23, 2005

tomustang said:
is it like a clank-clank-clank?

more like a dah-dah-dah-dah-dah at idle and then DAHDAHDAHDAHDAH as you go up in rpms.

here's what originally happened

1fast03pony · Dec 23, 2005

this all happened from an oil change??
jees

caballo · Dec 23, 2005

1fast03pony said:
this all happened from an oil change??
jees

not sure... but the real trouble began when the spark plug shot out the head...

mogs01gt · Dec 23, 2005

What are you mods and what type of plugs were you using. Stock or after market. You have to make sure you use the correct thread length on them, most people put too long of a spark plug into the PI heads.

correct threads

Does the sound seem to go away after your car hits operating temp? If so, it is probably a road knock or a wrist pin problem.

caballo · Dec 23, 2005

mogs01gt said:
What are you mods and what type of plugs were you using. Stock or after market. You have to make sure you use the correct thread length on them, most people put too long of a spark plug into the PI heads.

correct threads

Does the sound seem to go away after your car hits operating temp? If so, it is probably a road knock or a wrist pin problem.

stock replacement autolite platinums.

Sound doesn't change based on temp. sound only changes with rpm...

caballo · Dec 23, 2005

otra bump

mogs01gt · Dec 23, 2005

caballo said:
stock replacement autolite platinums.

Sound doesn't change based on temp. sound only changes with rpm...

hmm, do you see any drop in oil pressure?

triggz · Dec 23, 2005

Send your oil off for analysis at Blackstone Labs. They'll likely be able to diagnose your problem.

They can detect trace amounts of pistons, bearings, and block shavings from unwanted friction.

Youve got a good candidate motor for this kind of test. It's only $20 too.

http://www.blackstone-labs.com/

sgarlic · Dec 23, 2005

For a knock sound that's happening while you drive, it's hard unless you have access to a lift, or have friends who will get up under the car to listen while you jack the rear end up and spin the wheels.

I know this sounds harsh, but if it were me, and I were hearing a continuous knock while driving, I'd be buying a cheap beater car to drive around while I pulled the motor from the stang to diagnose.

caballo · Dec 27, 2005

sgarlic said:
For a knock sound that's happening while you drive, it's hard unless you have access to a lift, or have friends who will get up under the car to listen while you jack the rear end up and spin the wheels.

So I unplugged each spark plug (one at a time) while the engine was running and the sound didn't change. Then I put a piece of pcv(no hose available) up to my ear and went up and down both valve covers and didn't notice a change in volume.

So I'm thinkin' maybe it's a valvetrain or timing chain thing...

Any thoughts?!

caballo · Dec 27, 2005

bumpalicious

willit · Dec 27, 2005

Was your spark plug whole? (missing pieces) Entertain the possibility of ingestion of pieces. Did you do a compression test? Would rule out valve/piston/ring issues. Does the noise change with clutch in/out? Does the sound occur only under a load? Dissect your oil filter to look for any "floaters" metal, etc. How many miles on motor?

caballo · Dec 27, 2005

willit said:
Was your spark plug whole? (missing pieces) Entertain the possibility of ingestion of pieces. Did you do a compression test? Would rule out valve/piston/ring issues. Does the noise change with clutch in/out? Does the sound occur only under a load? Dissect your oil filter to look for any "floaters" metal, etc. How many miles on motor?

plug was whole.

Compression test good.

Auto; no clutch.

Sound is constant. increases in frequency with rpms... (slightly louder)

81k miles on motor.

Diagnosing engine knocks...

caballo

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