When is the port injection active?

[Blue By You]

For those of us that have it, is it kind of in sync with the DI during regular use or only active in WOT pulls?

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[geep81]

Don't quote me but it's in sync with the DI in normal use.

At lower RPMs the DI is stronger, I am convinced this is why people think they have a "2k rattle" because the DI kicks on in that range and is much nosier than port injection.

I do not know about during WOT.

 

[junits15]

It varies depending on the situation. In general the car uses DI more than PI, but all injectors are always used at some point on basically ever drive you take.

At WOT all 16 injectors are running, the bias is heavily towards DI (like 90% DI). At cruise and part throttle it can vary from 100% DI to 100% PI.

It tends to idle in PI, you can force it to DI with a tune and it is so noisy it sounds like a diesel lol.

 

[engineermike]

The short answer is it follows the following table. The % is the % of the calculated required fuel that is sent to the GDI injectors while the balance is sent into the port injectors:

The row axis is engine load.

There are about a dozen caveats to that table, though. For instance, it uses a different table when cold. There's also a GDI pressure relief cycle where it will turn on GDI if the stagnant rail pressure goes to high, thus the blend will come off 0 for a short amount of time. Also, at WOT it prioritizes the warm blend table posted above, but if the GDI injector open time fills the entire window, it will switch to prioritize fuel mass flow over blend %. In other words, once the GDI injector is doing all it can do, it will let the blend fall automatically and send the rest through the PFI injector. If the PFI injector hits its limit, then it will modulate the throttle to ensure it can hit target lambda (unless the tuner disabled this feature). Another cool thing, as far as I can tell it actually has dual LTFTs, one for PFI and one for GDI. This makes sense because the injectors may be erroneous in different directions and it would throw off trims if you applied the same correction to both.

 

[keepnitsimple]

Thank you engineermike! I have been looking for that information. Where did you find it?

 

[EFI]

Where did you find it?

Google, second search result from Engine Labs.

https://www.google.com/search?q=gen...CDg5MjFqMGo3qAIAsAIA&sourceid=chrome&ie=UTF-8

 

[engineermike]

Thank you engineermike! I have been looking for that information. Where did you find it?

For me, lots of testing and tuning.

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