Knock at idle

[WarWagon]

Now what?!
At a hot idle the 1993 'patch' has a loud knock. (As in Dad with hard of hearing issues can hear it.) It goes away completely when I raise the RPM. It will also knock under light throttle. Again going away with heavier throttle.

Dad thinks it's an injector. 30K on Bosch nozzles with 2 stroke in the fuel is not likely IMO. Esp when the knock goes away with more fuel added.

I didn't see anything major on a visual of the HB and belt drive.

 

[THEFERMANATOR]

Crack the injector lines open at idle one by one and see if you can isolate the sound. Sounds like an injector to me.

 

[WarWagon]

Can't hardly get an ear on it as it comes and goes so much. Caught it today in drive at a stop. The converter rock guard is the loudest - not in oil pan or on injectors I can reach. Do hear some noise on the intake. Thought it was the Dmax fan that started rubbing on the shroud so swapped it to the smaller diameter steel fan. No change.

 

[ak diesel driver]

I'd be inspecting the flexplate

 

[Will L.]

X2 on Les.

 

[WarWagon]

Found it and don't have to swap the flex plate.

Bolt backed out.





Gonna get a better solution. I'll regret it later, but, later is the key here. Tempted to use red...

 

[ak diesel driver]

glad to hear it was fairly simple

 

[schiker]

Why are you going to regret it later. It will be hard to finger out once you break it loose? Or it might want to strip the head since they are short headed? Those are types of bolts that add time to my projects because I like to clean them up and remove all contamination from threads and prep so they go back in easy as possible under the truck.

Just use a little bit of Loctite and it won't be as strong but will probably do the trick (smaller drop/dot farther up the bolt towards the wrench head so it doesn't cover many threads). Putting too much on small bolts is usually the problem if you are worried about getting them out. Could also go with Green?, the lighter stuff. Oops on edit the low strength is purple. Green Loctite is penetrating.

As a side note....
Not too long ago I buggered a Mazda bolt that was tight. It was a flange bolt with factory rounded ish corners on the hex. I had used a twelve point socket. I have never done that before. Might have been a cheap socket that had worn but it was suppose to be the right size. I took that whole set of sockets out of my go to drawer and have them in a junk tool box set now. I bought a new set of 6 point sockets to replace them. Lesson learned on any bolt that is not a good looking regular bolt/nut use only 6 point good socket and take extra care. Might want to use 6 point wrenches for those bolts at least to break them loose when time to take them out.

 

[THEFERMANATOR]

I blue loctite ALL my converter bolts, and hqve no problems getting em out later on.

 

[Will L.]

Like Ferm, I ALWAYS use blue loctite on flywheel to TC bolts.
32 lbs torque on those guys.

Military/ AM General manual tells you one one time use. I almost always reuse them. But they say that with a lot of stuff, like every lock washer. IMO Replace all of yours now. The shearing force from the slight impacting to them on every revolution... Irritating to go get them, and the $15 vs if they let go.

 

[WarWagon]

I just take the engine or trans out often so I never noted the need before and that is why I worried about threadlocker on them. They had new bolts from Yank for the install. On the lighter side the crossover bolts have their annual anti seize treatment...