SPARK KNOCK Question

[Ballistik]

I had spark knock and I read on this forum to try clean the Mass Air Flow Sensor, and so I did. The knock dissappeared but then came back about 300 miles later. So I cleaned it again and it dissappeared again. This time for about 500 miles and now its back. Is the MAS bad or is it another issue. I cleaned it today and knock is gone. Any help would be great.
Thanks in advance.

 

[bergz0]

did u test it with a computer? any codes come up?

 

[bergz0]

The MAF (Mass Air Flow) Sensor is dirty or faulty. Note: The use of "oiled" air filters can cause the MAF to become dirty if the filter is over-oiled. There is also an issue with some vehicles where the MAF sensors leak the silicone potting material used to protect the circuitry.
There could be a vacuum leak downstream of the MAF sensor


In the vast majority of cases, simply cleaning the MAF sensor does the trick. Consult your service manual for it's location if you need help. I find it's best to take it off and spray it with electronics cleaner or brake cleaner. Make sure you are careful not to damage the MAF sensor, and make sure it's dry before reinstalling
Inspect all vacuum and PCV hoses, replace if necessary
Check for a dirty fuel filter and proper fuel pressure

 

[GPRACING]

spark knock

I had a similar problem with my 1994 explorer.It was the air tube from the air meter to the throttle body had a crack in it.Replaced it and no more spark knock.But if you clean the air meter and it goes away then that mite not be your problem.Just a sugestion.

 

[Bent Bolt]

Make sure the air filter fits the housing very,very well. I've seen more than 1 badly fitted air filter screw with the MAF reading. Would also explain why the MAF is getting dirty.

 

[Yellowsplash]

I find it's best to take it off and spray it with electronics cleaner or brake cleaner. Make sure you are careful not to damage the MAF sensor, and make sure it's dry before reinstalling

Dont use brake or carb cleaner....they are too harsh for the MAF element. Go to your local auto parts store and pick up a can of CRC's MAF cleaner. Its about $6 bucks a can. Just take about 5 mins to clean the MAF everytime you change your oil. This will keep your truck in top notch condition assuming this is infact your problem. Dont be afraid to use some carb cleaner on the intake piping, lower intake gasket, vacuum hoses, ect. to check for leaks and fix as necessary. And as said above, replacing fuel filter and checking fuel pressure would be a next step.