Spark advance table changes

[gullwingmagazine]

Im running an MSII ver 2.3 and Megatune 2.25

When I change the spark table and burn to ECU it stays that way while you are working with it but when you reboot the ECU it reverts back to the previous settings. The ECU seems to be remembering other changes. Any thoughts?

Ron

[Bernard Fife]

Ron,

MegaSquirt has two versions of the settings - one in RAM, another in FLASH. At start-up, the FLASH copy is loaded to RAM and used from then on. The RAM is what you are changing when you make adjustments.

Then when you 'Burn to ECU', the current RAM settings are copied back to FLASH. The reason we don't want to burn to FLASH immediately on every change is that burning to FLASH is slow and complicated (an entire page must be erased and then burned at once).

So if the burn to FLASH fails, then the settings revert when you power back up (since they are retrieved from the original setting in the unburned FLASH). Typically this happens if the voltage to MS-II is too low. I suppose it's possible to have a failure if not enough time is left for a burn too.

Lance.

[gullwingmagazine]

Okay, this makes sense. I definately have a hot battery/good connections and I think I have given it plenty of time to burn to Flash... any other thoughts on why the settings are gone when I reboot?

Ron

[Bernard Fife]

Ron,

Make a datalog with the battery voltage included.

In MS-II batteryVoltage is already in the [OUTPUT CHANNELS] so you just have to add it to the [DATALOG] section of the INI file.

Add a line to the datalog section of the INI:

Code: Select all

entry = batteryVoltage,  "VBatt",       float,  "%.3f"

That will let you know what MegaSquirt is getting for voltage.

Other possible causes are a corrupted MegaTune INI file, a corrupted MSQ, or corrupt code. I would:

1. Save your current VE, spark, and AFR tables by exporting them,
2. Unstall MegaTune,
3. Rename MegaTune and project folders in C:\Program Files\MegaSquirt (so that clean version will be created, rename them to car1_old, or something similar),
4. Reload the code,
5. Import the tables,
6. Enter the remaining values by hand.

Then you know you are starting with a clean copy.

Lance.

[gullwingmagazine]

Im sorry Lance... this is where my lack of computer skills slows me down. Can you give a bit more detail on how to get to the ini file and datalog section.

Again, I apoligize for my lack of skill in this area... but Im learning.

Ron

[FoundSoul]

I just made that ini hack for you and emailed it to you-- just drop this file in your C:\Program Files\MegaSquirt\MegaTune2.25\mtCfg and datalog when you are “burning to ECU” and you’ll be able to view battery voltage during a burn and upload that here needed.

It would also be good to go through the other steps Lance outlined if the battery voltage doesn’t appear to be the issue—you can export the tables from the table’s respective screen. File>Export. Then you can follow the rest of Lance’s steps.

[gullwingmagazine]

Lance, here is the datalog you asked for

Ron

[gullwingmagazine]

Attached is a recent msq file

Timing during cranking is 8-10 degrees btdc

The longer you crank the harder it tries to start.

All plugs are firing, all injectors are squirting

Help

Ron

[gullwingmagazine]

Just a side note, while cranking and trying to start I get 1 foot flames out of the headers. I checked the timing at cranking rpms and it comes in at 10 btdc. Any thoughts? This thing is really trying hard to start and I am running out of ideas

Ron

[Bernard Fife]

Ron,

Did you see the tips here: http://www.megamanual.com/v22manual/mtune.htm#howto

There's nothing unusual in your datalog, except the battery voltage is very low. It may very well be that this is not enough to physically open the injectors, at least not reliably. So you might need a charger on the battery, or better connection on the power and ground.

Lance.