Megasquirt Support Forum (MSEXTRA)

There appears to be a bug in this firmware as well as 1.5.0.

Batch fire using "std fuel" aka "v3 outputs" results in unequal outputs on the 2 injector channels. This occurs with all combinations of simultaneous, alternating, with 1,2,4, or 8 squirts (v8 configuration tested only).

This is *not* with sequenced batch enabled, but the results are nearly identical to the problem that MS2 has with sequenced batch enabled. Due to the already existing suspicion about sequenced batch, no tests were performed with it enabled.
This problem does not present itself on the MS3x output pins of J1 on the MS3 daughtercard, the issue is only on the V3 outputs which impacts users upgrading from MS2 that aren't otherwise making wiring changes.

Initial symptom was identified as unequal fuel between banks without running dual table fuel. Output difference was verified with a multimeter and a stimulator on the bench.

Hardware was verified using output test mode. In test mode both outputs do match, 2 scenarios tested.

Full test results are available here. https://docs.google.com/spreadsheets/d/ ... sp=sharing

The tune file used to generate the results is attached.

You've found a real bug there. I found your data a bit confusing, but scoping it confirmed a problem.

What is currently happening is that the greyed out bank 2 deadtime is always being used regardless of the "different" setting. That's bad.

I'm investigating the code error, but here's the workaround.
When using V3 (mainboard) injectors. Set "Bank 2 different" and set bank 2 to use the same deadtime as bank 1.

James

jsmcortina wrote:You've found a real bug there. I found your data a bit confusing, but scoping it confirmed a problem.

What is currently happening is that the greyed out bank 2 deadtime is always being used regardless of the "different" setting. That's bad.

I'm investigating the code error, but here's the workaround.
When using V3 (mainboard) injectors. Set "Bank 2 different" and set bank 2 to use the same deadtime as bank 1.

James

Thanks James. Yeah I don't have a scope (really starting to see the need for one) so I was using A/C voltage on my multimeter as a way to simply gauge if duty cycle was higher or lower between the channels.

Thanks for investigating the work around, it'll give it a shot.

Confirmed the workaround on the bench. Should be able to run it in the car in an hour or so but I fully expect the issue to be resolved now. Thank you!

Thanks for posing this bug. I was really wondering why I had 2 plugs that were black and 2 that looked clean.
I also confirmed that enabling the second bank deadtime and resetting the values to be the same as bank 1 did indeed work.

This issue was solved long ago and the fix is in the current release firmware.

James

so people using any previews firmware should update to 1.5.1 release.thanks

elturbonitroso wrote:so people using any previews firmware should update to 1.5.1 release.thanks

Yes. Ideally two years ago.

James

Thanks James, The plan is to update but this fix got me by in a pinch. I didnt want to do a full FW update right before traveling 4 hours.