efil4ynot

Last night I passed my neighbor on the way home and decided to lug the engine real good and smoke him out. This is the only time I've ever really tried to get her to smoke and when the smoke started pouring out the engine started to knock real bad. I could feel it in the floorboard and it was in time w/ the rpms. I left off the throttle and w/ black smoke still pouring out my tailpipe, I came up to my turn and as I slowed down the knock started to go away. After a few seconds it was totally gone. I took it real easy through our subdivision and got on it just a little a couple times and there wasn't any knock at all. It was also idling just fine in the driveway. And today it seems to be running pretty good but may be a little extra smokey.

So, anyone have any ideas? It really scared the poop out of me. Someone told me that it may have been a chunk of carbon that broke off and got into the piston. Does this sound right? The last couple of weeks I haven't been driving my truck anywhere but back and forth to work, which is in town about 15 min away so that theory could make sense.

Thanks.

mitternocht

Was it a bad case of timing rattle? Maybe the engine wasn’t up to full temp and the added smarty timing caused it?

efil4ynot

Crap, I forgot to mention that. No, this was most definitely not timing rattle. I really thought that a rod was going to shoot out the block but it cleared up just when I was about to turn off the truck. It lasted for about 10 seconds. And everything was up to full operating temps.

Raspy

You wouldn't feel a piece of carbon through the floor board unless it was a big chunk that was getting crushed. And that would probably be over quick.

Sometimes if you flood a cylinder to the point that it actually has liquid fuel sloshing around, it will run at full power on that cylinder and normal power on the rest, until the excess fuel is burned. It will puff smoke and knock severly. I had this happen on a Perkins that was partially hydrauliced with fuel on one cylinder. Maybe you have an injector problem and it sort of stuck open a bit while lugging at full throttle. Then, that cylinder had to clear itself.

05 CTD2500

Exhaust or something else coming into contact with something solid maybe?

BigIron70

I get that noise when I change my injectors. When I pulled injectors out some raw fuel got down in the cylinders. When I first started engine it will hammer for a few seconds. Sounds like the piston or rod knock. Now when I change injectors I will always blow some air into cylinders until I blow out all the raw fuel. Doesn't hammer when I start it up then. You must have had a ton of raw fuel in cylinder took time to burn it out.

Tedonlin150

How did you lug it with an auto?

efil4ynot

Well, I think I'm going to go w/ the excess fuel in the cylinder mostly b/c I was lugging it so much and there was an unbelievable amount of black smoke. It seems like this would be hard to do w/ stock injectors though, am I right? Or is it more likely b/c they've got a lot of miles on them and maybe one or more is getting a little leaky?

Also, to lug it I waited until the TC locked up (about 50 mph or so) and then slowly rolled into the throttle w/o letting it downshift but also dumping just enough fuel to keep the turbo from lighting up.

mitternocht

Hopefully noting is damaged. That would have scared me too; I’d have needed new underwear.

Raspy

That's not lugging it in my book. And certainly not hard enough to get excess fuel in the cylinder. If it's at 50 MPH and not even lighting the turbo, it's not lugging. That's just regular driving around.

NickBeek

My truck did this when I had bad injectors. Are you getting white smoke and rough idle first start of the day? I believe it was an injector hanging open for a few seconds that caused the knock and rough running. Keep an eye on your oil level, if it starts rising don't drive the truck until you get the injectors checked out.

efil4ynot

Hmmmm. Well, maybe lugging isn't the proper term but I was b/w the point where it wouldn't downshift nor would it spool the turbo. And I kept laying into the throttle more and more to keep it at this point to keep it smoking. I'm not sure how else to describe it but I know that I was dumping quite a bit of fuel into her....

And no I'm not really getting too much rough idle or white smoke first thing. Every now and then she'll have a little lope to her in the morning but it's been that way for a couple years or so. And yes, I have been checking the oil level for that reason. Injectors are next on the list but I'm still trying to replenish our honeymoon funds after I spent it all on the tranny. Hopefully this spring unless they get real bad.

utah9412valve

well my buddy has a 2000 cummer and when he really lugs it out it makes the knocking sound also its just because all the unburnt fuel in the engine

utah9412valve

oh and also my buddy just put some fresh 75 horse injector nozzles and has a edge comp....he said it makes that knock ever since he got the nozzles ....which is more fuel so i think it is just that raw or unburnt fuel in the engine causing it to knock