A loaded question...

Testing and development of Megasquirt 3

Moderators: jsmcortina, muythaibxr

Post Reply
subwoofer
Super MS/Extra'er
Posts: 884
Joined: Sat Apr 30, 2011 12:34 pm
Location: Sandefjord, Norway

A loaded question...

Post by subwoofer »

Load is used all over the user interface, but in some cases it is hardly clear which load each load refers to. On my install, there are three different loads controlling different aspects;

1. Ignition load is referenced to MAP
2. AFR load is referenced to TPS
3. fuel is controlled by MAF

So when the AFR/EGO dialog says "Active above/below load" which load does it reference? AFR table, ignition or fuel? Logically it should be either AFR or fuel, it wouldn't make sense to refer ignition load, but which one is it?

Likewise in the closed-loop PID activation criteria: Max decel load. It would make sense that it is fuel (in this case MAFload), but it's not specified.

I know I run an odd setup and that most people will only use one load parameter, but it would really help understanding if this was a bit more specific in places. If I was using primary/secondary loads as well it would be even more ambiguous.

Everything is in reference to the current state of the art, pre1.4b12.
Joachim
1974 Jensen-Healey
1990 VW Caravelle Syncro - running MS3+X
2014 Ford Fiesta EcoBoost
TheSilverBuick
Experienced MS/Extra'er
Posts: 357
Joined: Thu Feb 02, 2012 9:08 am

Re: A loaded question...

Post by TheSilverBuick »

Isn't Load simply MAP/Baro? And if a baro sensor isn't being used it's pretty much just MAP?
"Hey, at least the Skylark proves that even a messy hack can patch together a reliable EFI system. I can't think of a time the MegaSquirt has left me stranded since installation ~100,000 miles ago."

Drag Week 2011, 2012 & 2015. - BB N/A - 1977 Skylark w/Buick 455 EFI and TKO-600!
subwoofer
Super MS/Extra'er
Posts: 884
Joined: Sat Apr 30, 2011 12:34 pm
Location: Sandefjord, Norway

Re: A loaded question...

Post by subwoofer »

TheSilverBuick wrote:Isn't Load simply MAP/Baro? And if a baro sensor isn't being used it's pretty much just MAP?
No. What load is depends on what sensors are installed and how you choose to use them.

BTW: A baro sensor is just a MAP that only measures ambient atmospheric pressure, it is not capable of providing any load information.
Joachim
1974 Jensen-Healey
1990 VW Caravelle Syncro - running MS3+X
2014 Ford Fiesta EcoBoost
PDX5
Helpful MS/Extra'er
Posts: 44
Joined: Mon Nov 03, 2014 11:08 pm
Location: Portland, Oregon / Washington, DC

Re: A loaded question...

Post by PDX5 »

I agree that the load reference is a bit vague. However, it should be easy to determine what load is actually being used for each setting. For example, Idle Advance and Closed-loop idle will be using MAFload. AFR/EGO is a little difficult to determine, but it should be MAPload (I'd double check since they could be TPS in your case). And overrun fuel cut should also be MAPload.

I had similar confusion and eventually figured it out by testing a few threshold ranges to get an idea of what load was being used. Simply adding the info the the tooltip would be very helpful.
Post Reply