Injector data, idle tuning and cold starts

[sbarisic]

So i got some ford/bosch injectors 0 280 158 117 (0280158117) which i'm trying to use with the E78 ECU on the 1.4T engine.

All the data i find on the internet isn't helpful at all, and the car doesn't seem happy with anything i try.
Here's the current values which work, there's no stuttering and the wideband seems to follow commanded pretty okay.

There was also a problem with the short pulse adder, the values in this table are basically random right now.
It used to "misfire" and basically stutter when WOT at about 1500 RPM and up. That showed up as a lean spike on the wideband and sudden vehicle jerk.
But that's fixed now. I think there's a bug with HPTuners here, as this table seems to be offset by 1 compared to older operating systems when comparing the stock data.

The Injector Pulse Width in the log is of no help at all.

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Except there's a problem with cold starts and idle.
On cold starts it's running leaner, and that's okay. But the car is basically undrivable the first minute until it warms up a bit.

It seems like it runs in two "modes".
Cold starts are okay in the first one where it's basically dumping more fuel than required, but then it suddenly switches to some "lean" mode and AFRs go way above 15-16 and it starts stuttering.

This is what it looks like when the car is warmed up. The "lean" mode (right part of the graph) follows the 14.7 AFR commanded just fine, but the rich mode makes the car idle at 13 AFR.
What's going on here?

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They switch every once in a while, it's either too rich or running at stoic.
Maybe it's catalyst related? But i can't find any place to turn it off.



Tune and log

CorsaE14T2019_Injectors.hpt

injectors_7_300_wb.hpl

My injector calculator helper spreadsheet

FuelInjectorCalculator.xlsx

[Spcbrn]

Hi,

I'm looking forward at replacing the stock injectors for the same (0 280 158 279, same as yours except this the long version) on my 1.4T and the info available on the net about these isn't very helpful as you said.

About your cold start problem, when it suddenly goes lean is the car still in open loop or has it switched to closed loop control?

I have no precise idea about why your car would run rich at idle when fully warmed up. As you said, it could be to keep the cat warm enough to do its job.
Some older versions of VCM Suite allowed for more options about catalyst stuff (disabling post O2 sensor test and more) but for some reason they dropped these features in the newer versions...

Good luck!

[sbarisic]

Hi,

I'm looking forward at replacing the stock injectors for the same (0 280 158 279, same as yours except this the long version) on my 1.4T and the info available on the net about these isn't very helpful as you said.

About your cold start problem, when it suddenly goes lean is the car still in open loop or has it switched to closed loop control?

I have no precise idea about why your car would run rich at idle when fully warmed up. As you said, it could be to keep the cat warm enough to do its job.
Some older versions of VCM Suite allowed for more options about catalyst stuff (disabling post O2 sensor test and more) but for some reason they dropped these features in the newer versions...

Good luck!

Closed loop, happens when the car is warm too except then it switches between perfect stoich and ridiculously rich.


I'm gonna replace them with the stock injectors and see if the problem persists and post results within next week. Could be that i fudged some other table that i should not have. That or i have some hardware issues.

[PSYKOSTEVO]

Curious, why did you set our Injector Flow Rate table to be flat at 51.7, instead of scaling it from stock based on the flow rate difference between the stock injectors and the new injectors?

The injectors will flow a different amount of fuel based on different pressure, so would you have more luck using a strategy where they flow around your 51.7 in the 408kpa area, and then less below that and more above that, like the stock injector strategy?

[sbarisic]

Curious, why did you set our Injector Flow Rate table to be flat at 51.7, instead of scaling it from stock based on the flow rate difference between the stock injectors and the new injectors?

The injectors will flow a different amount of fuel based on different pressure, so would you have more luck using a strategy where they flow around your 51.7 in the 408kpa area, and then less below that and more above that, like the stock injector strategy?

That applies only to the cars that have a FPCM and can vary the fuel pressure. This fuel rail has a vacuum referenced fuel pressure regulator.
And sadly it doesn't have a nipple where i could test the fuel pressure compared to some others, so that complicates things more.


51.7 flow for this injector is at 300 kPa, and not at 400 kPa.
Most of the information i find online is wrong, measurements made using heptane aren't equivalent to gasoline because of density differences.
You need to know your local gasoline density to be able to correctly calculate all of these tables. Online information shows gasoline density in the range 700–800 kg/m3, and n-heptane is listed at the following values if you google enough 684 kg/m3, 679 kg/m3, 614 kg/m3 at standard pressure and temperature.

A 50 lb n-heptane (680 kg/m3) measured injector at 3 bar flows 52 lb gasoline (720 kg/m3) at 3 bar.
This was sold to me as a 525cc injector. The car had properly calibrated fuel on standard injectors, i swapped for these and got correct (commanded = measured lambda) wide open throttle static flow at 51.7-52 lbs with them.


In the meantime i found the fuel injector clinic HP tuners data, and slapped it in the tune, which makes things work fine.
Except for cold starts which are very lean, and sudden throttle opening results in lean spikes, i guess too much wall wetting, and the fact that the intake manifold is polished and has no thumblers doesn't help.
I'll check the bin file with WinOLS, there should be some more compensation tables we don't have access to in HP Tuners. Unless somebody else has an idea how to tune transient throttle conditions with HPT?

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There's an off-by-one bug in VCM Editor for 12314 short pulse adder table. One is a stock value for 2017 car, which is ok, the other is a stock value for 2019 car.
When i touch the 4ms field, it results in a misfire at about 2000 RPM. But one can work around that when you know what's up.

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