Calibrating Ignition Timing

[z-ya]

Hello,

I have my MS2Extra 3.4.2 installation up and running with a 36-1 crank wheel and wasted COP configuration. What I am trying to do now is calibrate the ignition timing with a timing light. I am trying to calibrate it using the "Ignition Settings -> Ignition Outputs -> Tooth #1 Angle BTDC" in Tunerstudio. I can set a positive value for the "Tooth #1 Angle BTDC" setting, but that moves the timing in the wrong direction. When I try to enter a negative value, I get an error. Right now my timing is retarded about 5 deg, which I can account for when setting up my timing table, but I would rather not have this fixed offset. Is there another place where you can calibrate your ignition timing in Tunerstudio?

Thanks,
Pete

[BlackBird_SR71]

You are going to have to change your Sensor mount position, or turn your Trigger wheel.

The missing Tooth #1 has to pass the VR sensor about 60 degrees BEFORE the piston reaches TDC. You have it at 0.0 degrees, which is not going to work.

The ECU needs to see the Missing Tooth with your Maximum ignition timing ( RPM = Load ) which can easily be 40 to 45 degrees total at cruise, plus it needs some thinking time ( in degrees of crank rotation ).

This usually comes out between 60 to 70 degrees lead time BTDC for the missing Tooth to pass the VR sensor. IE 45 ( Timing ) + 15 ( Thinking time ) = 60 BTDC . All figures are approximate.

[z-ya]

Yes, I was looking for this information when I was mounting the sensor, but couldn't find it, so I ASSUMEd that I should set it at TDC. This goes against my experience as I've done a few EDIS installs which require the sensor to be at 60deg BTC. So, it looks like I f'd up!

Here is a stupid question, what if I set "Tooth #1 Angle BTDC" to 355deg to achieve the 5 degree negative offset?

[rickb794]

Here is a stupid question, what if I set "Tooth #1 Angle BTDC" to 355deg to achieve the 5 degree negative offset?

This is the same as timing it on the other half of the cycle and will not work.

[z-ya]

Thanks for the response.

I am using a DIY trigger wheel, so I was able to unbolt it from the crank damper and move it one slot. This puts the missing tooth at 40deg BTC. I was able to calibrate the timing spot on!

[BlackBird_SR71]

Thanks for the response.

I am using a DIY trigger wheel, so I was able to unbolt it from the crank damper and move it one slot. This puts the missing tooth at 40deg BTC. I was able to calibrate the timing spot on!

40 Degrees is not going to be enough. You are likely going to run into stability issues when the Timing advances at higher RPM's and while cruising. ECU is going to run out of " Calculation Time " under Maximum advance situations, which is always at light throttle and Cruising. Most engines will require 40 to 45 degrees Total advance at cruise to maximize fuel economy .

For example. A stock Nissan RB26 timing curve uses 50 degrees BTDC at cruise. My 450 HP SBC with 10.5 CR ran 44 degrees Total advance at 3,000 rpm and Cruise. Pulled 23 MPG while towing a trailer!!

You want at the missing tooth passing the VR sensor at least 60 degrees BTDC. It can be more. 70, 80, 90 100 etc. Move it another slot, or move the VR sensor. You can buy adjustable VR sensor brackets or design a new bracket.

[prof315]

Simply not true. On a missing tooth wheel you can use ANY #1 tooth angle. It's basic trigger that doesn't like the trigger angle inside the firing window.

[BlackBird_SR71]

Simply not true. On a missing tooth wheel you can use ANY #1 tooth angle. It's basic trigger that doesn't like the trigger angle inside the firing window.

The method I recommended is the method recommended by MS. You may be able to get away with using other settings, but will result in " Funky " #1 Tooth angles as you essentially have to detect the missing gap on the previous cylinders exhaust cycle. It can be done, but is probably over the head of a New User and adds unnecessary complexity.

This is the recommended DIYAutoTune MS2 configuration for a 6 cylinder engine with a 36-1 trigger wheel:

Last Updated: 9/29/2009

This web page covers how to configure Megasquirt for our line of 36-1 trigger wheels. See the main Megasquirt trigger wheel page for more details on the trigger wheels, including how to install them on your car. In this article, we will use the standard orientation described in the installation guide. Here’s how many teeth the gap should be ahead of the VR sensor to use the settings in this article. You’ll notice that the settings for 4, 6, and 8 cylinder engines are the same as the settings on stock Fords.

Edit: Updated with link. https://www.diyautotune.com/support/tec ... k-trigger/

Number of cylinders Missing tooth location at TDC
1 9 teeth ahead of the sensor
2 9 teeth ahead of the sensor
4 9 teeth ahead of the sensor
6 6 teeth ahead of the sensor
8 5 teeth ahead of the sensor
12 8 teeth ahead of the sensor
The output mods assume you will be using wasted spark type coils without built in ignition modules. Examples of such coils include Ford EDIS coils, GM 2 tower DIS coils, Dodge Neon or V6 coil packs, or our IGN-4 coil packs. If using coils with built in ignitors such as GM LS1 coils or IGN-1A coils, you will need to change the output circuit.

[BlackBird_SR71]

Z-Ya. Is this on a Datsun L28 by any chance? Doesn't really matter. But for a 6 cylinder engine, move the wheel so that the missing Tooth passes the VR sensor at LEAST 6 Teeth before when the engine is at TDC. For the reasons I mentioned and as MS instructs.

[prof315]

Z-Ya. Is this on a Datsun L28 by any chance? Doesn't really matter. But for a 6 cylinder engine, move the wheel so that the missing Tooth passes the VR sensor at LEAST 6 Teeth before when the engine is at TDC. For the reasons I mentioned and as MS instructs.

I repeat NOT NEEDED. Optimal, yes. Slightly quicker starts, possibly. And DiYAutotune is NOT MS, they are the largest distributor of Megasquirt products. They didn't write the firmware or design the ECU. I have run missing tooth tiggers at just about every possible #1 tooth angle without issue as high as 9500 rpms.....

[BlackBird_SR71]

Z-Ya. Is this on a Datsun L28 by any chance? Doesn't really matter. But for a 6 cylinder engine, move the wheel so that the missing Tooth passes the VR sensor at LEAST 6 Teeth before when the engine is at TDC. For the reasons I mentioned and as MS instructs.

I repeat NOT NEEDED. Optimal, yes. Slightly quicker starts, possibly. And DiYAutotune is NOT MS, they are the largest distributor of Megasquirt products. They didn't write the firmware or design the ECU. I have run missing tooth triggers at just about every possible #1 tooth angle without issue as high as 9500 rpms.....

Sigh.... sSo why make things more complicated for the poor fellow than it needs to be with a non-standard configuration? Yeah you can do a work around? But why bother when a simple and effective method is already recommended and has information readily available. Really. seems like you are just splitting words to prove your point. Point taken OK?

I forgot to include the Link to the above mentioned article. I've edited that post now.

The linked page shows configurations for BOTH B&G software and MSExtra software... which do develop the Firmware now. And I'm sure you know that DIYAutoTune works pretty darned close with the MSExtra developers. Hardware wiring for all board Versions and Firmware versions as well. Better?

Done with this line of discussion...

[prof315]

I'm not the one posting inaccurate info. Ask James ( jsmcortina) if the current generic wheel decoder needs to be where you say it does. He wrote it. And the link from DIY is 9 years old! MS2/Extra was at V2.1x and and the decoder still in its infancy.

[hybrid]

I agree with prof315.
Once the 36-1 has sync, the ECU knows exactly where the crank is based on the tooth count.
It shouldn't need the missing tooth to calculate timing like a basic trigger does, otherwise what's the use of having a toothed wheel over a single basic trigger?

If the missing tooth does not end up where the ECU count says it should, it will lose sync.
Personally I would be verifying either way with the devs before doing any more work.

By the way, it's been a while but I'm pretty sure the Extra code says the trigger angle can be almost anywhere, but the factory set it at X, so err towards doing the same. It definitely doesn't say you HAVE to set it there.