DI HPFP control strategy

Hey guys!

It would be nice to see a guide on "how to tune Direct Injection pump control" that goes in depth on the cam lobe profiles, control valve hold angle, start angles, close time, etc... just to name a few of some of the require parameters. And the pros and con of synchronous and asynchronous pump control.

Is hard to fine a real in depth information out there.

Cheers!

I second that. I'm thinking about retrofitting a Gen V LT2 in my GTM. Would be awesome to see an HP Tuners and/or aftermarket ECU walkthrough on the GDI specific parameters.

I couldn't agree more, there's very little information about that topic. And not to mention every ecu uses different parameters for the GDI pump control.

The hardest thing about making any training on this topic is the complexity of the of control.

You have two methods of getting the required information: getting access to manufacturer datasheets that cover in depth the requirements of the control strategy, or reverse engineer the system as best as possible.

For reverse engineering of a system, you need the engine already running on a factory engine control, or access to a r&d vehicle to determine some of the information.

You need to be able to scope the pump with a multi channel scope to determine peak pulses, peak and hold currents, the switching frequency the factory ecu is able to achieve this at (as the aftermarket ecu may not be able to achieve this) as well as hold angles.

Your need to measure a pump lobe in engine with a degree wheel and the follower in place, so you can determine the actual lift profile acting on the pump plunger.

You need manufacturer data on the piston diameter so that the pumps maximum displacement can be determined - based on the cam lobe lift. If you can't reliably get data for this, you need to disassemble the pump to measure it - which many pumps are not servicable, so this requires a donor pump to be destroyed to get the required information (again if you cannot get the required information)

You then require to get the correct pump phasing information, so that the pump control is correct. This again varies depending on whether a pump is driver of a cam or auxiliary drive. If it is an auxiliary drive, you need to determine if there is any reduction in place (many systems that use this style have a sensor on the auxiliary shaft.

The workflow and required information for aftermarket control will be different depending on the ECU used.

You also have normally open, normally closed and proportional pumps that are used.

Further to that, many controls work on an interaction between how much fuel the pump is delivering in relation to how much fuel the injectors are delivering. You then require data as accurate for the injectors as you do for the pump for everything to work in relative harmony.

So the process is time consuming, requires some not inexpensive tooling if reverse engineering is required and if bad data is used in any point of the setup, it is challenging to diagnose or rectify.

Thanks for taking the time to explain all of that. It really puts into perspective how deep this stuff goes and why getting reliable data is such a challenge. In my case I’ve already measured my cam lobes with a degree wheel so I could map the lift and work out my start angles. There are still a few parameters I’m trying to wrap my head around, things like stroke length in crank degrees, control valve hold angle, close time, hold duty, etc. The good thing is I can still move back and forth between the stock ECU and the standalone, so I’m slowly piecing it together.

I even sent my DI injectors out to get opening/closing time data, but I didn’t end up getting the info I was hoping for. It seems hard to get this data as well. But anyway, I’m planning to pick up a scope soon so I can finally see the pump behavior properly (hopefully).