besel53

2014 3.5EB... About 43K miles. Bear with me, I'm new to the Turbo thing, but very mechanically minded.

I bought my "new" truck about a month ago. Really loving it for the most part. Figured since I read about these EB's eating plugs I would change them right away since they were still OG. SO, I put in the new plugs, gapped at .028, and had the battery disconnected with the lights on to reset everything. After hooking battery back up, turned key to "on" for 10 seconds, started, idled for 10 mins, then went on some drive cycles taking it easy on it. There wasn't anything funky with the truck, started and ran like a top, old plugs were anywhere between .038-.041 after replacing, but didn't look too bad otherwise. The only other thing I have done is drilled the weep hole, and I cleaned all 3 MAP sensors with CRC MAF cleaner all done before reset.

Truck started right up and ran great immediately after the plug change. Here's my issue though now:

After about a week, I started to get some rough idling and black smoke puffs right on startup. After about 5-10 seconds, some valve or something pops open and it smooths out after that. There has been a couple times that the valve (or whatever is opening) opens up, it starts to smooth out, then I hear it close again and it putts and puffs a little more until it cracks open again.

What is opening up shortly after starting? Is it some kind of pressure release from the turbo going into the TB? Or is it the TB itself cracking open? Controlled by PCM? (Which I reset again just to be sure). I pulled the plugs again this last weekend and re-gapped to .030 just to see if it made any difference. It didn't.
Here's a vid, you will hear it about :09 seconds in.

besel53

No ideas?

5.0nly

After a quick google search, the black smoke out of the exhaust seems to be normal. Also, on my eco trucks, I've noticed on a cold start that the turbos will kick in a couple of seconds after start up. The rough idle is a hit or miss as some of my trucks do it and some don't.

Pickupman66

mine does this too. form all the reading I have done, I think it is something to do with the timing, direct injection and the turbos. I think what you hear opening is the blow-off valve relieving pressure created by the turbos initially. it seems that the system pressures up on startup and then releases down after a few seconds.

I have never noticed any black smoke but from past experiences (carbed engines) this is due to a rich fuel mixture. Part of this programming richens the fuel/air mixture to assist in quickly warming the block.

FWIW, I just remote start mine after it has sat for a while (cooled) either overnight or at work so it doesn't bother me.