yea maybe just go and have them take a look and see what it is and get a estimate just to kno how much

 

spark knock, as u call it, is that caused from the rod thing in side the cylinder (i forget what its called) hits the bottom of the spark plug? wouldnt that be a bad thing to happen?

 

Justin, bad news is they will charge you to fix it. The cost will depend on the fix itself - doing just the primary tensioner, or the secondary tensioner as well. To replace the secondary tensioner, the engine needs to be pulled (at least $1,200 for the total job).

"Good" news is, save your money. Under warranty, I had this problem addressed twice - first they replaced the primary chain, and that didn't do it. Second, they replaced both entire timing assemblies including chains, and that didn't do it either. Thing is, I've never heard of anybody actually getting it fixed, it always seems to return. I spent a couple of weeks going around and around with Ford to no avail. I've learned to live with it, and just stay below 2500 RPM until it warms up.

Give this thread a read...

http://www.ford-trucks.com/forums/sh...g+chain+rattle

 

What is spark knock and what do you do to fix it?

 

hmm they charge for TSB's? I had a TSB on my crappy 93 mazda.... like, two years ago - before my truck, and they didnt charge me, i forget what it was for... but then, they lost the key to it, and to make a long story short, theres only 2 keys for that car that will work, factory master keys will not work. so, well i btched them out over that. they finally found it, but then had the ***** to yell at me cause their master eky didnt work!

 

No, spark knock is nothing like that. It is defined as "a mild to severe ping, usually worse under acceleration, w/ the engine making a sharp metallic knock that changes with throttle opening." It's usually caused by pre-ignition of the fuel in the combustion chamber, in other words, the fuel/air mixture being ignited prior to the introduction of spark in the cylinder. In the case of a Ranger, It would probably be caused by a faulty sensor, but high compression engines will have the problem if low octane fuel is used, or if the timing is advanced to far. I don't think a piston in a 4.0 or any Ranger engine would ever hit the valves because they have fairly low compression, and they have plenty of clearance, even if the valves were open at the same time the piston was at tdc. If the connecting rod, which attaches the piston to the crankshaft, ever were to hit the spark plug, it would be a failure of catastrophic proportions, and your engine would be puking its innards all over the street....so yes, that would be a very, very bad thing.

 

Thats how they explained it to me too.. I tried higher octane gas and I didnt hear the spark know anymore.. Im not going to always run 93 but I just wanted to try to see if it will clear it and it seems to have for now.

 

That's the thing. These trucks don't need that kind of octane because they have low compression and mild timing. You might want to clean your mass air flow sensor and see if that clears it up. Mine was getting really bad, and as soon as it was cleaned, it ran as good as new, and the gas mileage got ALOT better. When your maf sensor gets dirty, your pcm gets false readings and you get a lean condition resulting in spark knock.

There are two schools of thought on cleaning a maf sensor. One is to simply spray it w/ aerosol electronics cleaner (a fast evaporating, non residual spray), and the other is to swab them w/ denatured alcohol. Here's a link to a article about it. It's a well known problem, and this will explain what and how to clean the sensor a little better:

http://www.rrorc.com/forums/showthread.php?t=23894

I think the sensor is held in place w/ those tamper resistant torx head bolts w/ the peg in the middle of them too, so you'll have to procure the proper bits from an auto parts store.

 

Cool thanks for the info, i will give it a try.

 

ill have to go pester D about this, since he is the local Ranger Gear Head.