I have a 94 ford explorer that has had a knock/ ping in the valves for some time, though not bad at first, it is now almost all the time. I have put in a new egr valve, platinum plugs, pcv and it seems to get worse. I use premium gas and have used octane booster, but it gets worse. any help would be grewatly appreciated.

 

1st can you positively identify the noise? Is it valve train noise (would be most noticeable at idle)? Is it spark knock or ping (Would be most noticeable under heavy load on the highway?

 

The most common reasons for engine knock on the 4.0 are (in no particular order):

*MAF sensor needs cleaning
*Lower intake manifold bolts need to be retorqued
*Engine needs to be decarboned. Ford has issued a TSB on this.

The MAF sensor cleaning and the decarboning proceedure should be in the Ranger forum in the sticky titled technical information. BTW, the TSB concerning decarboning advises against using premium as this can contribute to carbon buildup and engine knock. Hope this helps.

 

I have had the same problem with our 94 since it was new. First try what CowboyBilly suggested. I did all of that to mine and not much help.

What did help me was to run a can of B&G 44K through the fuel tank. It is avaliable at NAPA. After I ran most of the gas out of the tank, I refilled using regular unleaded. Then on a weekend morning when I had time, before starting the engine, I removed the ground lead off the battery and let it set for 20 min. This will clear the engine computer. Then rehooked the battery lead and strated the engine and let it idle untill the engine was up to normal temperature. It is important not to touch the throttle during this time.

Now take it out and drive as you always do. The PCM should LEARN to run on regular fuel without pinging.

I hope this helps.

 

The sound I hear is the valves. I am not sure what a knock or a ping is. I do know that it sounds like the valves are chattering away. Most of the time it is under medium to heavy load. Going up hills, starting from a stop with good throttle,and sometimes when accelerating while cruising. Was it bad to use premium gas? Even if not required, wouldn't it burn cleaner? Or are fords just different?
Thank all of you who have given my good advise for fixing my problem.

 

I would suggest you fiind someone who knows what spark knock sounds like and have him/her ride with you. Because it occurs mostly under load as you describe it, I expect it's spark knock or ping. Cowboybilly9mile pointed out the three most common causes of ping.
However, if it is valves as you believe, that would point to an oil problem (low pressure or something) which requires a different treatment. Like I said, though, valve train rattles are usually most pronounced at idle (when the oil pressure would be at its lowest).
My "over the internet" diagnosis is that the noise you are experiencing is spark knock, and I expect one or more of the items above should fix it.
About using premium gas, octane number does not measure how much energy a gasoline contains, or how cleanly it will burn or anything like that. Octane is actually a measure of how difficult (relatively) it is to get a given gasoline to burn. The higher octane, the more difficult and slower it burns. The details of what happens when an engine pings are out there if you want to look them up, but, as I understand it, engine ping is essentially a symptom of the gasoline burning too soon or too quickly. (That's areguably an oversimplification, but it helps me to think of it this way.) On an engine that isn't designed to run the higher octane, you actually have a greater chance of leaving deposits behind because the fuel doesn't burn completely. Note that it can be somewhat of a gamble whether you will actually see it or not: some people regularly run higher octane on these without a problem, others have seen it. On the other hand, an engine designed to run on high octane that is run on lower octane will likely ping, because it expects (via timing curve, compression ratio, etc) the gasoline to take longer to burn.

 

I just wanted to say thanks to Mr. Shorty and Cowboy billy for their ideas. I took off the MAF and the first wire was thick with black gunk. After some spraying and some gentle brushing with my finger, all that goo was gone! And now so is my pinging!!!!!!!
She is back to her old self. Not much power, but sooth not much power, and will rev. like before. THANKS again. You guys saved me a lot of money. Very nice.
Intelligence on the internet, YOU GOT TO LOVE IT!!!!!

 

Good to hear it all worked out. Just a suggestion; I like to use an artist brush and work the cleaner gently around on the MAF wires while spraying some cleaner to flush away dirt. Then follow up with compressed air, or just blow on it to dry it and remove any remaining debris. Now isn't it funny that Ford feels people should replace the MAF rather than clean it............................