My F-150 ecoboost runs super rich when first started when cold. So rich that it will puff the black/unburnt fuel from the exhaust. This will happen when just idling or first accelerating off when the engine is completely cold.
Once the engine is warm the exhaust looks fairly clean
Anyone else noticing this?
PS I am aware that all engines run richer when cold until warmed up. But I just want to see if all ecoboost engines are doing this.
Big thing about turbo's..having been around them for a long time. Don't spin it up for a couple of minutes at start up and if you have been pulling hard and long and things are hot you want to idle it for a couple of minutes before shutdown.
Especially on the shut downs the turbo can be spinning at several hundred or more rpms. imagine that it is spinning at 5K rpm's and you shut it down after you got to the top of the 2 mile 7% grade with 10K behind you. You see a rest area and just shut it down.
Here is a small section of an article I found about the ecoboost that was written a couple years ago. It did not state that this was specifically the F-150 spec engine, but all things being equal this might explain why we are seeing some soot around the tail pipe ends when it's cold out and the engine is cold:
Since the system direct-injects fuel into the chamber, games can be played with the actual flow of the spray. For instance, on start up, when the engine is cold and the catalysts aren't functioning, the engine injects a half-shot of fuel into chamber on the downward stroke of the intake cycle, then, as the piston comes back for ignition, a second half-shot is fired at the piston head. Notice the shape of top of the piston (sans the CNC'd EcoBoost logo): The little trough is designed specifically to ramp that secondary spray at the spark plug — the result is a locally rich mixture good for ignition, but a globally lean mixture, great for making heat fast.
As said above, it appears they are making a rich mixture for quick warm up and smooth running when cold. Normal for a rich mixture when cold, but a strange approach to me. Kind of sucks actually. Seems the best thing to do is get in it and drive vs letting it idle and warm up. Not suggesting it gets hammered on until the oil temps are up to snuff, but drive it nicely while it warms.
My old ecotech (LNF block) in my Saturn Sky Redline would put out black puffs whenever doing any hard acceleration, same exact technology as the ecoboost. I think it's just a little bit rich for a short time because the engine is trying to quickly up the boost. So just like diesels, they dump fuel trying to maximize energy in expanding exhuast gases to get those turbines to speed. It usually lasts for just a short burst because of that slight lag before the engine gets enough oxygen to match the injected amounts of fuel. I think this is an inherent problem with Direct Injection/Turbo Charged engines. But the nice thing is that you're not dumping profuse amounts of fuel that the older port-injected turbo engines do (Subaru's, Lancer Evolutions, etc...) to fight PING/Knock, so those puffs of black are short lived.
EDIT: And also, I wanted to throw this out there. A lot of people don't realize that these turbo's spin at speeds up to 220,000rpm (that is not a mis-print) when they're putting out full boost. So there is lots of friction. If you know you're getting close to where you're going to shut off the vehicle, drive easy, let the engine cool while you're getting there, then you don't have to worry about idling before shut down. Otherwise if you have to run it hard until you hit your destination, make sure you idle it for at least 2 minutes to get the turbine down to acceptable temps and avoid coking on the bearings.
turbo chargers spin from 130k to 200+k rpms. if you put your ear up to my tailpipe, you can hear it spinning for about a min after shutdown..
nice to let them cool down for a bit, but they design it so its not required to sit there a few min and let them cool. good quality oil goes along way..
to spin 200+k rpms, there is not alot of friction. otherwise it would never com close to that rpm range, or free spin after shutdown.
My bad, I didn't mean to put lots of friction, but I meant there's little friction, but still lots of heat soak. And you can have that oil coking issue if you're not using a decent oil (I prefer synthetics in that regard).