Dual fuel injection function

[Mosey]

Today I learned something new (at least to me). I was always under the impression that on the 3.5l Ecoboost, the port injection system ran under low load conditions and the direct injection took over under load at some point. Yesterday I was playing around with my Innova scanner to see if it would read tranny temp, which it does not, but discovered it does read injector system A and B usage. So out for a drive I went.

At idle the B injectors were reading 100% indicating that they are the port injectors. As I drove the A system (direct injection) would start to take over. What surprised me was that I never saw a time where the port injectors were completely off, even under full throttle. So from what I saw, the intake valves are always seeing some fuel pass over them and hopefully helping keep valve coking down.

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[Vater]

That is excellent to know! Thank you as keeping those intake valves clean is a concern of mine, ie, I have run BG and Techron in gas as an additive several times but am feeling like I am n a better place knowing they are gas bathed constantly

 

[Bob Violence]

Found this ...

"However, the port injection only runs during idle and low speed conditions. Higher speed and higher load conditions mean the engine is running direct injection only. So, build up still occurs, albeit much more slowly. "

https://www.ford-trucks.com/articles/3-5l-ecoboost-carbon-buildup-solved/

 

[Bigguy214]

I saw a video on that awhile back that Ford changed that to do exactly what your talking about to keep the carbon buildup from getting so bad.

 

[dochawk]

I saw a video on that awhile back that Ford changed that to do exactly what your talking about to keep the carbon buildup from getting so bad.

There's a piece written on a cadillac forum by one of the engineers that designed the Northstar engine.

Carbon buildup can be an issue, he explains, as they never considered the possibility that anyone would drive it like a grandma!


Anyway, his suggested solution was that monthly or so, you put it in first gear, and accelerate full throttle to freeway speed !(that early electronic transmission would shift when needed).

 

[Eskram]

Anyway, his suggested solution was that monthly or so, you put it in first gear, and accelerate full throttle to freeway speed !(that early electronic transmission would shift when needed).

Th ol' Italian tune up!

 

[SALEEN961]

This is what the stock DI/PI blend tables look like on my 2021 3.5EB, 100%=100% Direct Injection Fueling and 0%=100% Port Injection Fueling.

 

[Vater]

Yes! It looks like the port injection is on all the time, but blended down inversely proportional to DI picking up more duty.

 

[Gros Ventre]

Another method of reducing the buildup is to install a CatchCan. I did so and it has collected a bunch of "stuff." Much more in wintertime.

 

[starcommtrey1]

That is excellent to know! Thank you as keeping those intake valves clean is a concern of mine, ie, I have run BG and Techron in gas as an additive several times but am feeling like I am n a better place knowing they are gas bathed constantly

This^^^^^
YES! This will keep our valves clean for a few hundred thousand miles and should promote an extended idle from us everynow and then!

 

[Probity]

Yep. From 7+ years ago:

Explained: Why Some Engines Have Both Port and Direct Injection (caranddriver.com)

Each maker uses a different strategy regarding when to use port, direct, or both injectors. One of Toyota’s torque versus rpm versus injector use maps is shown here.
Peter Dowding, Ford’s chief engineer of powertrain gasoline systems, revealed a different strategy. Ford uses PI alone at idle and at low rpm for smooth, quiet, and efficient engine operation. As rpm and load increase, fuel delivery becomes a programmed blend of PI and DI. In contrast to Toyota’s methodology, Ford’s PI is always operating, responsible for at least 5 to 10 percent of the fuel delivery.

 

[Mosey]

I was just watching an “I do Cars” video of a tear down of a 2.7 liter Ecoboost with 130,xxx miles on it. This engine has dual injection like our 3.5s

He bore scoped the intake valves, and while the intake port walls had carbon buildup, the intake valves were clean. I don’t know where the port injector is located but it must be close to the valve.

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