Engine Knock - Ford TSB for Decarbonization

[Snort]

I've seen a lot of folks asking about the decarbonization process to help with engine knock. I found the Ford TSB for decarbonization on the web, so I thought I would post it up. Information is power.

Engine - Carbon Knock On Acceleration
Article No:
01-19-7

10/01/01
^ ENGINE - 4.0L OHV - CARBON KNOCK ON ACCELERATION

^ NOISE - CARBON KNOCK ON ACCELERATION - VEHICLES EQUIPPED WITH 4.0L OHV ENGINE ONLY

FORD:
1990-1997 AEROSTAR
1990-2000 EXPLORER, RANGER

ISSUE
Some vehicles equipped with the 4.0L OHV engine may exhibit an engine noise which may be perceived by the customer as a piston/connecting rod bearing knock. This carbon knock is heard only under load during the drive cycle. Carbon knock is a customer drive duty-cycle phenomenon that cannot be repaired with an engine exchange. This may be caused by carbon build-up within the combustion chamber.

ACTION
Verify condition. If normal diagnostics fail to correct the condition, de-carbon the combustion chamber to help quiet the carbon knock noise. Refer to the following Service Procedure for details.

SERVICE PROCEDURE
1. Use Motorcraft Carburetor Tune-up Cleaner PM-3.

2. Carbon removal:
a. Disconnect canister purge line from throttle body.
b. Attach a vacuum line to the canister purge port.
c. At hot engine idle, allow the engine to ingest 1/2 to 2/3 of a can of Motorcraft Carburetor Tune-up Cleaner. Use caution not to ingest too quickly due to potential hydro-lock issues.
d Shut engine off and allow it to soak for one hour.
e. Start engine, allow engine to ingest the remainder of the Motorcraft Carburetor Tune-up Gleaner.
f. Remove vacuum line and re-install canister purge line.
g. Road test vehicle at 3500 RPM for 2-3 miles.
h. Repeat above procedure two times for a total of three times.
i. Change oil and filter.

3. Review the customers' driving habits. The recommended drive cycle should include daily periods of engine operation above 3,000 RPM, such as a brisk acceleration from a stop position. This will break/burn the carbon off the piston head.

4. Use regular unleaded fuel, 87 Octane. Mid-grade and Premium fuels may increase the probability of carbon buildup, leading to a knock noise.

 

[Alec]

Quote: 3. Review the customers' driving habits. The recommended drive cycle should include daily periods of engine operation above 3,000 RPM, such as a brisk acceleration from a stop position. This will break/burn the carbon off the piston head.

I take care of that

 

[Crankcase]

Originally posted by Alec


Quote: 3. Review the customers' driving habits. The recommended drive cycle should include daily periods of engine operation above 3,000 RPM, such as a brisk acceleration from a stop position. This will break/burn the carbon off the piston head.

I take care of that

LOL

That is why my Explorer doesn't knock as much as the one owned by my slow accelerating Dad.

 

[Lemondrop]

4. Use regular unleaded fuel, 87 Octane. Mid-grade and Premium fuels may increase the probability of carbon buildup, leading to a knock noise.

Even with Ford saying that ....... it's amazing the people who won't believe it . High octane fuels are for race cars

 

[Alec]

Or race trucks

 

[jrfranz]

Its becuse most people in the States don't know what octane is - and they just always assume that more expensive is better. I know people that like to brag that their car "needs" premium fuel and that it keeps their engine cleaner - and amkes their car have higher horsepower - mostly becuse they know someone with a high performance car and have heard them say that and want everyone to think they have a high perfomance car too.

I never thought about the carbon build up problems - but it does make sense as the resistance to detonation of the higher octane fuels would not burn as completely in a lower compression engine.

Jeff

 

[rvitek]

Originally posted by Lemondrop


Even with Ford saying that ....... it's amazing the people who won't believe it . High octane fuels are for race cars

Think about the last fuel commercial you saw. Those marketing folks do a wonderful job of promoting high octane fule to the laymen. Why not? Results in good profits for them.