Ready to tackle the 6G72

[dcreel]

Hi Folks,

I've been away from here for a very long time, and unfortunately my 3000GT has also been dormant for a very long time. Some of you might remember I was working on a 6G72 wheel decoder for MS1/E a while back, and I was fairly succesful. However, I never got the car running completely due to time constraints and possibly bugs in the base code at the time (029T i think).

I am trying to decide between just adding the 6G72 wheel decoder to the current MSe code, or upgrading to the MS2/E.

What is the current level of support in the MS2E code for a 6G72 decoder, and are any of the developers willing to actively pursue it with me? I know exactly how the ignition waveforms look, and I can prove it with a scope. I have also done a fair amount of GCC coding, so I'm sure I could write it myself if I have to.

There is a third option, and that is to develop a board to go between the stock signals and make it look like a normal wheel. I had this worked out a while back too, but dropped it in favor of built-in support from making code changes.

[jsmcortina]

Although my time is limited at the moment, I'm keen for someone to test out the 6G72 code and either prove it works as-is or help develop it to a working state.

"It looks good on the stim"

James

[dcreel]

Well then, you have your volunteer. I will go buy a MS2 board and start making the modifications for the upgrade.

[dcreel]

Ok, I have made the modifications, with a little twist of my own.

I have determined that the outputs from the 6G72 sensor (at least mine) are open collectors. So, I basically wired up two pull-ups to vcc and sent that to the sensors. IRQ and JS10 will therefore have same-polarity signals as recommended.

I took a look through the 6G72 code, and it looks like it should work. I had trouble keeping up with whether edge and edge2 are inverted, and how they get set. This is my first look at the MS2 code, so forgive my ignorance.

FYI I will be attempting to use the FIdle for boost control, use the built-in IAC control (might have to rewire my stepper), and JS11 for fan control.

If this works I will do some sort of write-up.

[dcreel]

Speaking of write-ups, I noticed the online docs said the code should be able to handle COP if there were enough outputs.

Is there some way o re-route JS4, JS5, and JS7 for this purpose? It looks like they are used for extra features that would be unused in many installations. Or are they input only?

[jsmcortina]

Is there some way o re-route JS4, JS5, and JS7 for this purpose? It looks like they are used for extra features that would be unused in many installations. Or are they input only?

JS4,5 are ADC inputs, but _could_ I suppose be used as general port pins for output.
JS7 is input only.

As we'd had comments from an MS builder suggesting we stick to less variations in pin usage, we had intentionally curtailed our use of too many different pins.

James

[dcreel]

I'm guessing it would introduce a lot of noise to use them as GPIO?

That makes sense I guess, but it would be nice to be able to offload some functions onto a CAN board and reuse some MS pins for spark to do COP for >= 6 cyl.

Anyway, I'm just hoping for wasted spark right now hehe. I am going to try it right now, and I will post back here in a couple of hours.

[jsmcortina]

The two ADC ports can easily be reconfigured as general I/O without creating noise, but probably the first thing that would happen is someone wants to log EGT, use realtime baro, knock etc. at the same time as 6cyl COP.

We need a CPU with more I/O.

James

[dcreel]

We need a CPU with more I/O.

such as the AVR 32
I am using one to call a webservice (ethernet) via the LwIP stack and FreeRTOS, *and* be a USB host for HID class devices and Mass Storage devices at the same time. That thing is awesome for a microcontroller.

Check it out if you have time/interest for other projects www.atmel.com/avr32


BTW, it seems like the 6G72 code is mostly working. I have had 2 starts, but no stable idle yet. I drained the battery trying to crank with the coil outputs on the wrong coils I will try again in a couple of hours and post back if I get an idle.

[jsmcortina]

It ran though?

Is it keeping sync?

James

[dcreel]

It ran though?

Is it keeping sync?

James

Not really. I will post a video in the morning. Here's a primer on the situation:

The Coils have 12v coming from the switched side of the FP relay. They drain through 3 vb921s. I put an oscilloscope probe between a coil and it's driver. I use the 'test outputs' mode to verify the coils with the scope and a timing light. When the FP is on, I can see 12V on the scope. When the coil fires, I can see the drop and spike on the scope and the timing light flashes. I tested all 3 coils successfully.

Now for starting the car:
I have priming disabled. When I turn the key, I can see the rpms pick up to about 150 and the FP activates. However, even though I can hear the FP come on (and its relay is feeding the coils), the scope still shows 0V. This means my coils are always draining during this time?! Sometimes I can get it to behave correctly by switching it off and back on quickly after the FP has activated. In that case I get the 12V with spikes on the scope and the car will start and run for about 1 second.

So it seems like most of the time the MS is seeing RPMs, activating the fuel pump, and yet not sparking. I have the 'skip pulses' thing set to the minimum of 3.

Does it have something to do with the priming maybe?

[jsmcortina]

Can you post your MSQ and a datalog ?

James

[dcreel]

Datalog and msq

EDIT: sorry, I added .1ms priming pulse during the datalog. updated msq to reflect this.

[jsmcortina]

How are your coils wired/fired ?
Is the code keeping sync? Or does the sync light flash on and off?

James

[dcreel]

Here is the video. In the last segment, it does stay at 0v on the scope until I let go of the key. Then it jumps to 12v.
http://www.youtube.com/watch?v=scxf6VD22Z4

And see the attachment for how my sensors and coils are wired. The coils fire inverted and I am triggering on falling edge for the sensors - is that correct?

[jsmcortina]

And see the attachment for how my sensors and coils are wired. The coils fire inverted and I am triggering on falling edge for the sensors - is that correct?

I'm not sure on the correct edge now, how about if you swap that setting and try again?

There are two phases to testing - the first is to get sync during cranking with the injectors and coils unplugged. Until it can get and keep sync there's no point in trying to start.

Once it can keep sync, then you can try connecting up the injectors and coils.

James

[dcreel]

There are two phases to testing - the first is to get sync during cranking with the injectors and coils unplugged. Until it can get and keep sync there's no point in trying to start.

Once it can keep sync, then you can try connecting up the injectors and coils.

James

maybe I could write a quick program on an AVR and have it output those 2 signals. It should take only a few minutes, and then I could see what it does on the stim.

I'll try it on rising edge and let you know first.

[jsmcortina]

Buy a JimStim from Jean... does it already !

James

[dcreel]

Buy a JimStim from Jean... does it already !

James

cool, a lot has changed while I was gone!
I was just getting ready to do the same thing.

I figured out what part of my problem was. Things were not wired up how I thought. I guess I changed it late one night out of desparation about a year ago, and then forgot. Now I am getting spark when I should.

However, it seems like as soon as the car starts it wants to lose synch most of the time. Here is a datalog. I think there are 4 attempts in there, the last 2 it lost synch quickly. Can you tell anything from the log?

[jsmcortina]

If I'm reading the log correctly, you aren't getting any PW during cranking!?

I can't immediately see anything wrong in the MSQ, but the engine certainly isn't going to run too well with no fuel !

James