VX / VY Flash ECU - Simulating running conditions on bench?

[Chr0m3]

Hi All,

I may be well in way over my head here, but I'm trying to run a VX / VY flash ecu on bench for testing, I've written up a spark cut rev limiter and tested on car as per this thread viewtopic.php?t=8567

I'm looking for the minimum amount of things I need hooked up to be able to simulate running conditions to test and investigate the spark cut rev limiter more on bench, has anyone done this before?

Ideally I like to be able to alter RPM and simulate the rev limiter so I can monitor everything on bench.

I'm good with software / reasonable at reverse engineering, I'd say I'm "okay" with hardware but definitely not great.

I have ordered an oscilloscope that can do signal generation etc, I have Arduino's etc too.

Any suggestions / help is appreciated cheers.

Edit: I have this all running on bench now, ecu in EST spark mode and seems to be happy and I'm getting EST output etc.

Pretty much just hooked up B10 to ground on an Arduino and B9 to a digital pin, wrote some code that allows me to input an RPM and it outputs a square wave 5v at the hz needed for that rpm, so thanks everyone for your input.

[pman92]

The REF input (crank reference, comes from ignition module) is just a 5v square wave. You could simulate its fairly easy with an arduino or signal generator.

The later ECU's had a direct connection to the 18x crank signal as well, I'm not entirely sure what for (maybe misfire detection? But I don't know). But it shouldn't be required.

From memory you might need some sort of MAF input or you won't have any injector output. They certainly don't start and run with the MAF unplugged.

But you shouldn't really need anything other than that.

[Chr0m3]

Cheers, these ECUs will start and run without a MAF if I recall correctly, so maybe I just need to simulate the DFI pulse and that was my original thinking.

[antus]

Power it up, ignition on, use your scope's signal generator if its 5v square wave, 50% duty cycle (if an option), and set it to say 1000hz and feed it in to the 3x input and see what you get?

[Chr0m3]

Power it up, ignition on, use your scope's signal generator if its 5v square wave, 50% duty cycle (if an option), and set it to say 1000hz and feed it in to the 3x input and see what you get?

Yeah that was gonna be my first test, but I'm still waiting on things to arrive so thought I'd ask to see if anyone actually knew or had done it.

Gonna try this with Arduino later on when I get some time.

I am wondering whether 18x will need to be visible to the ecu and if I'm gonna have to use an Arduino or something switch the signal after low rpm.

[Chr0m3]

Okay well I tried to apply a 5v square wave on the 3x input on the ecu, 1000 hz 50% DC and didn't get anything, back to the drawing board haha.

[pman92]

Okay well I tried to apply a 5v square wave on the 3x input on the ecu, 1000 hz 50% DC and didn't get anything, back to the drawing board haha.

1000hz would be 20,000 RPM for a 6cyl ECU lol

The ref pulse is 1 cycle per cylinder / coil firing event.

Try something slower.
EG. (1500 RPM / 60 seconds) * (3 cylinders fire each rev) = 75hz

EDIT: Also, the rising edge of the REF or EST signal is when the coils fire (see in the image its at 10 deg BTDC).
The ignition module is firing it directly from the REF signal when its not in bypass mode.
The EST signal sent back to the ignition module from the ECU is EXACTLY the same signal. It's just phase shifted to adjust ignition timing (If you watch them both on a scope with a running engine you can see them move relative to each other as timing changes).

[Chr0m3]

Okay well I tried to apply a 5v square wave on the 3x input on the ecu, 1000 hz 50% DC and didn't get anything, back to the drawing board haha.

1000hz would be 20,000 RPM for a 6cyl ECU lol

The ref pulse is 1 cycle per cylinder / coil firing event.

Try something slower.
EG. (1500 RPM / 60 seconds) * (3 cylinders fire each rev) = 75hz

REfPulse.png

Good point, should of mentioned I did try a variety of frequencies lower and higher haha no matter what I did nothing changed.

Didn't think it'd be right but I was just trying to get literally anything from it.

[pman92]

Good point, should of mentioned I did try a variety of frequencies lower and higher haha no matter what I did nothing changed.

Didn't think it'd be right but I was just trying to get literally anything from it.

Are you checking for injector pulse?
Or EST signal?
Or data logging to see RPM?

Haven't forgot to turn VATS off if your just checking injector pulse?

[pman92]

Also, confirm the ref signal is going into pin B9.
And the signal generator or whatever your using is grounded to the same ground as the PCM and B10.

VX Flash ECU Wiring.png (109.4 KiB) Viewed 8372 times