Iposted abouta deep and low yet intermittentknocking noise a few weeks ago. It was loudest near the driver's side of the oil pan.

In the past two weeks, I've done the following:

1. Swapped oil to a straight 30 weight.

2. Replaced the spark plug wires with Magnecors.

3. During the process of replacing the wires, I damaged the driver's side secondary air injectionY manifold. I replaced it yesterday.

I haven't been able to drive it much this past week with the manifold tear, but the noise persisted up until the time the wiresgot replaced. I couldn't hear any other noises save the exhaust leak during this time.

I'm still not able to take the truck for a drive as the front bumper is off getting repainted. However, the few times I've had it idling with the new Y pipe, the darn thing is as quite as a church mouse.

Usually, the knocking sound would come and go when the engine was cold and more intermittently thereafter. But after idling on several occassions for 10 minutes orso there's not been a peep.

I'm keeping my fingers crossed that it's gone for good. But I'm wondering if perhaps my problem was actually an exhaust tick or maybe even detonation that masqueraded as a rod?

 

Can't tell you but if it comes back e-mail me and I'll call you.

 

supposedly knock doesn't usually appear unless the engine is under load. If the motor was making odd noises when idling, chances are slim that it was knock.

Knock occurs when the fuel ignites too early or out of sequence, this can be caused by any number of things but back in the day with distributors it was usually due to too much of an advance in initial timing. Unfortunately with newer discos, the timing is electronic so that's probably not the culprit. The next thought would be the octane of the gas. The higher the octane, the more resistant the fuel is to detonation.

I wonder if maybe the wires that were on the vehicle to begin with were installed wrong? I'd imagine that could create a "knock" if certain cylinders were trying to fire at the wrong time...that's about all I could think of. Did you replace the spark plugs at the same time?

 

Theplugs were replaced a few weeks ago with 4 prong Bosch Platinums. I got two misfire codes and a check engine light that went away with the new plugs.

I had it at a garage for an unrelated matter and a mechanic said that the wires were beginning to arc. He said that grey and white lines in the otherwise black wires indicated that they were shorting.

I don't know if there's any truth to that, but they were rubbing against the aluminum secondary air pipes at the back of the engine.

After the swap, the truck idles smoother and remains steady at 750 rpm. Before it would fluctuate a bit.

 

I would say that your "knock" was a plug wire being grounded.

unstable-his knock was not gas related, he was thinking that it was a bad rod bearing as his trk was one of the ones with a bad oil pump. The oil pump exploded on the PO and he bought the trk from them and had it fixed, then the knock started after it was fixed.

 

Could also be the oil weight. I've found that going from 10W40 to 10W30 made my engine quieter. I figured that the thinner oil had an easier way to make it where it had to go as opposed to the thicker one. Since then, I've switched to full synthetic Mobil1 5w30 in the winter and 10w30 in the summer.

 

I had him switch to the thicker oil because we thought that it was a rod knock and a thicker oil will stop rod knock, it fills in the extra space.
He is OK to run the straight 30 weight in the summer/warm climates, even without a rod knock.

 

I have a simlar issue also,Slight per say tick,not a knock....off and on though,Figure performance is fine,why open a can of worms...next thing I'll be spending $ thousands........I drive 10 miles a day and weekends 200 miles.And have no problem....Look into it or leave all well alone?