TRiGGeR605

Hey guys,

I've been having some issues over the last few months with my truck. Occasionally when I accelerate hard I will get what I believe is engine knock followed by black smoke out the tailpipe. You can hear the tick tick tick and then look out the back and see smoke. I cant seem to produce the results repeatedly however. Sometimes it will go away for weeks and at other times it will be there consistently.

So here are my guesses as to what it could be -
Water in the intercooler finally getting forced through under load
Bad gas (I run 91 on an 87 tune)
Bad spark plugs (Changed at 30k miles and now have 40k)
Timing chain

Let me know what you think.

I should also note that I was running an 87 octane tune and today switched back to stock and on my first pull I produced the knocking so I dont think its the tune. I also always let the engine reach normal operating temperature before putting it under load.

Tothemax

I take it you have not drilled the intercooler hole?

Have you ran an entire tank of fuel through the truck? Have you tried adding some iso heat to the tank, to remove water if there is any?

Lastly, why run 91 octane fuel on a 87 tune?

TRiGGeR605

I havent drilled the hole yet. I'll start doing research on that. I've heard of a lot of guys doing this. As for the gas, I filled up at a different gas station from the one I always go to and havent had any knock since then. I've always run 91 because sometimes I switch to my 91 perf/tow tune. Lately I've been running the 87 tune to see if this will result in eliminating the knock, which it hasnt.

I have a hunch it may be the gas station I normally go to. They sell 91 with ethanol and regular 91 non ethanol. But the non ethanol pump is a stand alone pump and I never see anyone use it. Could it be that its just old gas?

Tothemax

Old fuel or water in the fuel.

agetech

Get the hole drilled before you slug a cylinder with water.

Sirikenewtron

I had the same exact thing on occasion with my first engine. I'm 99% sure it was crappy gas but I would get it even with a couple different stations fuel.
I tried everything to figure it out but never did.
I ran a catch can and had the hole drilled too and when I pulled my cac it was bone dry. (I thought it might have been moisture causing it also)
I did get it to do it much less when I started mixing about 4 gallons of e85 with the rest of my 36 gallon tank 91.
​​​

oneinch

My 2013 80K has rattled before. It isn't currently doing so. Unless I take a trip I rarely drive above 50 mph. I've experienced rattle while driving on cruise control at 35 mph. Going up a hill I'd get rattle. Manually downshifting from 5th to 4th stopped it. I questioned why the truck wasn't downshifting itself.

I did two things, but I do not credit either with doing anything, nor do I discredit them. I ran through a tank with fuel system cleaner first. I did the clearing the ECU thing to hopefully erase learned transmission shifting patterns. I didn't keep track of exactly when I did these things or any results of doing so. It could have been the gas. I usually purchase my gas at Costco. The rattling happened in winter. It's now warmer. For now I no longer hear rattling on the two hills I daily drive on. I have no idea why. Maybe it was gas my truck didn't care for.

Buzz944

Stu Cazzo

Black smoke? - water burns white or grey - oil burns black so whatever it is its oil, not water.

Honey Boo Boo

Any update to this? Having the exact same issue.