Engine Knock?
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From: SC
Engine Knock?
I have a 99 Expy 4.6 Triton with 135K. The number 4 spark plug kept getting fouled and I had to change it out every two weeks it seemed. Well, I tried to solve the problem and changed the wires and the coil pack. First, I changed only the wires and it was still misfiring. I changed the number 4 spark plug hoping that the one I installed was bad and then the engine started knocking really bad, however, the misfire was gone. Today, I changed out the coil pack and it's still knocking. The thing is that the engine sounds the same (knocks) with the wire to the number 4 plug connected as it does when it's not connected. Also, there is no misfire with the plug disconnected. Can anyone help me with this or point me in the right direction? Thanks.
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Joined: Jun 2004
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From: Orlando, Fla
Have you taken the coil pack and put another plug in it outside the head to see if its sparking? Because if its fouling, it can't be getting the correct voltage. The Ford EIC is pretty hot and should fire nice and white/blue hot everytime.
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It was firing red/orange. However, I drove it and once the tranny hit second the knock was gone. My mechanic said the knock was attributed to me using 20w50 in it at the last change. The lifters or something. I thought the fouling was from oil and that's why I changed it.
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From: Orlando, Fla
I would definately keep an eye on it, that oil is about as thick as you can buy and could create a situation where a lifter may not pump up. But the fouling shouldn't be from the oil and a red/orange color is a sign of a weak ignition. The weak ignition would be your most likely culpret for the fowling, not oil. If you have oil in your cylinder you have other issues.
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Another possibility is that you had so much fuel in your oil (from the dead cylinder) that it got too think to lubricate. Once you changed the oil and drove it some, it worked the oil into the system and the knock went away. I would definitely stay away from 20W50.. and use 10W30 at the VERY THICKEST. Personally I would stick with 5W30. (Ford now recommends 5W20 for almost all their gasoline engines, regardless of year). Motorcraft 5W20 is some really good oil.
Good luck.
Good luck.
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Joined: Jan 2007
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Have you ever considered a coolant leak as you miss fire problem? This is actually a common problem with #4 crapping out all the time. This happened to me with 160 K on my 5.4 Expy. The heater hose assembly goes right over #4 into the firewall and eventually develops a small leak. Enough where you could smell coolant and have to add to the tank, but not enough to cause puddles under the truck, steam or any overheating issues. The coolant will pool around the #4 plug and cause a miss fire. My truck would run on all eight. If I didn't use the truck for a few days and then ran it, it would run pretty rough, miss firing and display the engine light for a #4 miss fire code. If I ran the truck on the highway for a while, the coolant would boil out of the puddle and the truck would run fine. I would go home and shut the engine light with my code reader and the truck would be OK as long as I used it every day. The heater hose assemblies are not cheap but are worth replacing after over a hundred thousand miles to avoid those hassles or waste money on a new COP.
Stephen
Stephen
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From: SC
You were right sir. It was the coolant leaking from that hose. My guess is that it caused weak ignition and the fouling of the plugs were from that which crapped out the COP. I'm gonna get a new hose on Tuesday. Have a happy Memorial Day folks.
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