spark knock

[Mike02]

I have an 02 explorer and have been experiencing a lot of what I believe is spark knock.
I know a small amount of knock is ok but this seems to be excessive at times.
A friend of mine who is a mechanic and works at a ford dealer said he would check
For any new updates for the ECM and load them for me. Only found one that might
Help with the problem. It did not help. My X is stock except for the K&N air filter
System and Bosch double platinum plugs. Truck has 53k and I have owned it for
About six months now. How should I go about fixing this problem?
Thanks, Mike

 

[Ford_Racing_Guy]

I've heard that Ford Motors and Bosch plugs don't mix

 

[Mike02]

Changed plugs today, Autolite (OEM) still same problem. Don't know what to try next.

 

[BradE.]

Autolite plugs are not the same as Motorcraft. Ford is very picky about thier plug specs, and while they used to be made by Autolite, the Autolite plugs are not made to Motorcraft specs. Run some Seafoam through the motor, you might have carbon build up causing the knock.

What kind of gas are you running? Any misfires at any time?

 

[Mike02]

No misfires at all. Carbon build up possible but when I bought the X it had 50K on it so
that owner must have driven a lot on the highway. Does the 4L have a knock sensor?
My Mazda has one and it went bad at 60K but I got a check eng. light. Dealer has plugs at $7.95 each which sounds high to me.

 

[Cali' Explorer]

Mike02, $7.95 is excessive, but that's what ford Charges. If you have an Autozone in your area, go to them, they carry Motorcraft Plugs for between $4.00 and $5.00 a plug, depending on your area. You also may want to try the Ford Parts Network (www.fordpartsnetwork.com). They carry a lot of Motorcraft OEM parts for a lot less than your local Ford Dealer will charge.

 

[Ford_Racing_Guy]

i couldn't find Motorcraft at Napa or Advanced Auto, so i didn't even look at Carquest,

so i settled with some Autolite Double-plats for the car

 

[Mike02]

Changed plugs to Autolite, no change in spark knock. Filled up with 91 oct. and still sparknock. What next???

 

[Cali' Explorer]

Hehe, well, Autolites have the same problem as anything besides motorcraft in our engines. I'll takes some pictures when I have the camera, but I have a perfect example of what the difference is. I have 2 Autolite Double Plats and 2 Stock Motorcraft plugs that were pulled from my X. Both pulled from the same side of the engine. The 2 Motorcraft look exactly as the should, the two Autolites both show the signs of running too hit for the engine (blistered electrode and white charred appearance). I can't tell you which locations they came out of, but I can say that the two Autolites looked almost identical and horrible and the 2 Motorcraft looked fine (one had about 5k on it, the other had about 50k, and they both looked about the same).

I right now have Bosch's in my X and need to go change them out for the Motorcraft one's. Maybe this weekend if I have the time, but I would say that you should get the motorcraft's in before doing anything. You can even buy them online from Autozone if you want.

 

[Mike02]

Still hard to believe that you need to run stock plugs to keep from getting bad spark knock.

 

[MDPuckett84]

Could it be the timing chain rattle? that sounds like knocking around 2500rpm.

 

[performancenut]

Consider trying a lower degree thermostat. This has fixed primary knock and ping issues in the past for me. Probably due for a stat change after that number of miles anyway.

 

[Mike02]

Timing chain? can't hear it when in park and taking rpm up and down. As for thermostat i dont think so becouse i can hear it when the motor is cold. After i start the X and leave my driveway and go up a small hill i can hear what sounds like spark knock.

 

[Mike02]

Thanks everyone for the help on spark knock problem. Ford dealer said it was the timing chain tensioner and guides. Referred to TSB 04-15-4 which says noise is heard during hot and cold engine operation under acceleration between 2400-2700 RPM. To verify concern, accelerate in 2nd gear between 2000 and 3000 RPM
And listen for rattle noise that sounds similar to spark knock.

Action: replace primary timing chain tensioner chain guide, jackshaft sprockets.
Had to do a lot of talking to get it covered under extended warranty.