Ignition Timing and Tuner studio

[pablogwapo]

Hello,
Im currently a student currently working on a small engine (115cc). I am using tuner studio, speeduino and various sensors to measure output parameters given by the engine. I was told by one of the lab workers that in order to change ignition timing I had to go into the code given in a base tune and change it. I have not been succesful at that, I have tried looking for information but have not found any relevant information either. Would like to ask for your guys help and advice.

Thank you in advance.

[Max Welton]

I don't know anything about speeduino but TS certainly allows timing to be specified as a function of RPM and MAP (or %baro, TPS or MAF). No code change required.

Is that what you mean?

Max

[Bruce.m]

Tuner studio essentially changes the code or more correctly the parameters within the code, then you upload that to the ECU.

You need a some form of sensor or signal to identify crank position so you can determine rpm & when to fire the spark.

[Max Welton]

Hello,
I am new to this forum and not sure how to reply otherwise.

There is a button labeled "Post Reply" at the bottom of the last post in the thread. Use that.

Firstly thank you for your time and your answer.

I believe I was able to change it succesfully by going to Spark > Spark settings > cranking advance angle (deg) and from see how the engine reacts to different inputs.

That will only change the timing when the engine is cranking but has not yet started. How does the controller know when the engine has started? When the engine RPM exceeds "Cranking RPM" found in TS under "Startup / Idle" => "Cranking / Startup Settings".

Once engine RPM exceeds "Cranking RPM" timing is controlled primarily by "Ignition Settings" => "Ignition Table 1" on TS.

What sensors do you have on your engine?

Max

[pablogwapo]

Just so I understand it, the process I had previously mentioned of spark > Spark settings > Cranking Advance, only works for below cranking r.p.m.s and above that I should go to Ignition table?

Is the Igntion Table you are talking about is the following: Tuning > Ignition advance Table ?

Assuming so, what should I do there once its running, press to the greenest place at my running r.p.m ( my understanding of greenest is the most optimal place at running r.p.m). Press it and burn it?

Some extra explanation: After doing the process I just mentioned in parragraph two, I could see how the r.p.ms were affecetd by that and hence I assumed it was correct. (The engine does not run very smooth sometimes and it could have been that, I am not sure). I did several tests with different ignition timings TBDC (20,15,10). My problem is that when going to MegaLogViewer ignition advance only appeared to be 20 TBDC in all the tests.

Possible sources of error? Sensors or going to spark settings rather than ignition table.

Pablo,
Thank you for your reply, I appriciate it.

Is there any way I could upload pictures from my PC? Might bet easier to understand everything...

[Max Welton]

Just so I understand it, the process I had previously mentioned of spark > Spark settings > Cranking Advance, only works for below cranking r.p.m.s and above that I should go to Ignition table?

Yes

Is the Igntion Table you are talking about is the following: Tuning > Ignition advance Table ?

I get there via "Ignition Settings > Ignition Table 1". Looks like this:

IgnTable.jpg

Assuming so, what should I do there once its running, press to the greenest place at my running r.p.m ( my understanding of greenest is the most optimal place at running r.p.m). Press it and burn it?

You need to populate that table to give the amount of advance the engine requires at each RPM and load (MAP?) intersection and burn it to the ecu. When the engine is running the ecu uses that table to "look up" and apply the advance indicated. The ecu will also interpolate between adjacent cell values to give a smooth transition.

While the engine is running and TS is monitoring you can display the ignition table. TS will show which cell(s) are being applied.

If you use TS to log, the advance value logged is what the ECU should be applying. I don't think there is a sensor that would independently determine the amount of advance the engine is seeing. You could certainly use a timing light.

BTW, the msextra site has detailed explanations of how various things (like timing) are computed by the megasquirt ecu. Although I see that you are using speeduino.

Is there any way I could upload pictures from my PC? Might bet easier to understand everything...

As you compose your post, there is a tab called "Attachments" that provides a way to upload images and insert them into the post.

Max

[pablogwapo]

My process to obtain that same table is different Tuning > Spark Table.

When you said this "When the engine is running the ecu uses that table to "look up" and apply the advance indicated" is this process automatic or do I need to select the most optimal cell and then burn it?

"I don't think there is a sensor that would independently determine the amount of advance the engine is seeing" If a sensor can't read it t how can this tables be created? Is that what you ment?

Other than that I believed i have a good understanding of it. Thank you I will keep you posted with any relevant progress I am making.

[Max Welton]

My process to obtain that same table is different Tuning > Spark Table.

When you said this "When the engine is running the ecu uses that table to "look up" and apply the advance indicated" is this process automatic or do I need to select the most optimal cell and then burn it?

You burn the entire table to the ecu. The ecu uses sensed RPM and MAP to index into the table and apply the advance found at that cell. This is completely automatic and continuous when the engine is running.

"I don't think there is a sensor that would independently determine the amount of advance the engine is seeing" If a sensor can't read it t how can this tables be created? Is that what you ment?

I sense confusion. I may not be explaining this well. Population of the advance table is up to you. The values you put in the table are an expression of what you wish the advance curve to be.

Max

[Bruce.m]

Yup. I think you need to read the basic manual for tuner-studio / speeduino (mega squirt would also do to explain the the basics).

The human needs to populate the look-up table with the correct advance for any given engine state (dictated by the RPM & load). The ecu will measure the engine state, then look up the table & apply the advance supplied by the table. Deciding on what needs put in the table is a much longer conversation.

[pablogwapo]

Ok, thank you very much. I will keep you posted with any relevant progress. Have a nice weekend.

[pablogwapo]

Update: I was able to succesfully follow the steps and managed to get it working.
Next I will try adding an O2 sensor.
Thank you very much.

[Max Welton]

Good Job!

Max