A quick question regarding the start-up timing setting

david jenkins · Post by **david jenkins** » Mon Sep 03, 2007 3:01 pm

Brent,

Just want to clarify something, as I'm about to alter my maps - one cell holds the timing value to be used during start-up (cranking timing). Is it the cell shown below in red?

cheers,
David

MartinM · Post by **MartinM** » Mon Sep 03, 2007 3:11 pm

Yep, that's the one....

Post by **brentp** » Mon Sep 03, 2007 4:58 pm

Yep, that's the secret cell. It is selected when the RPM is below the measurable range (457 rpm). Soon to be officially documented.

mikaking · Post by **mikaking** » Tue Sep 04, 2007 11:25 am

What sort of value would be of benefit to help starting, a lower value? (I'm still using the generic map)

david jenkins · Post by **david jenkins** » Tue Sep 04, 2007 1:59 pm

Well, at my idling rpm the ignition advance will probably be around 18 degrees. I have found from previous experiments that there is NO WAY that the engine will turn over even once at that setting! I'll probably set the start-up value to around 10 degrees, maybe even slightly less.

Brent - once the engine is running, doesn't the extra-low value in that cell mess up the timing in that part of the map?

cheers,
David

rbalmford · Post by **rbalmford** » Tue Sep 04, 2007 3:52 pm

David,

I've kind of had some thoughts about this in this thread http://www.autosportlabs.org/viewtopic.php?t=1330. How it affects you depends upon whether you are running TPS or MAP: for MAP, you wont get full vacuum (top line on map) at idle; whereas for TPS it will use the top line at idle, and hence produce a possible conflict between cranking advance (say 5 degrees) and desired idle advance (say 20 degrees or more).
Solutions for TPS:
1) sacrifice column 1 of the map for the cranking advance using an rpm value of 500, and start column 2 at 600rpm with your desired idle advance (assuming your engine idle > 600rpm!!);
2) get brent to provide a 'switch' in the global controller options to select whether it uses the top-left (for MAP) or bottom-left (for TPS) cell during cranking (hint hint......)
3) ........?

Rich.

david jenkins · Post by **david jenkins** » Tue Sep 04, 2007 6:57 pm

I'm using MAP - but I have set the top line to a realistic value, so I might use it occasionally.

I have a suggestion for (3)

Get Brent to blatantly copy the method used by the Emerald fuel injection & ignition system - have a box on the options page that holds the cranking value, totally independent of the ignition map. That system uses that cranking value until the engine is running at some particular speed, at which point it swaps over to the normal map values.

It would save having to mess up that corner of the map...

David

Post by **brentp** » Tue Sep 04, 2007 7:47 pm

I had suggested that option a while back: configuring as a separate parameter- likely in the "global controller" configuration options. I'm not familiar with the Emerald ECU.

In retrospect I think this is a superior approach. However, it wouldn't be part of the switchable ignition configuration, if you have that enabled.

I will put it on my to-do list- however, if you're interested in having it sooner you're welcome to take a crack at modifying and making available a custom firmware image.

Regards,

david jenkins · Post by **david jenkins** » Tue Sep 04, 2007 9:38 pm

Emerald can be found here. Think of it as a commercial equivalent of Megasquirt. It's quite a popular system in the UK, but it's not cheap. However, it is very versatile and can be applied to a wide range of engines. It's certainly a lot easier to get running than MS but, as I say, you have to pay for that simplicity.

I don't think I'm up to modifying code just at the moment!

cheers,
David[/url]

fikus01 · Post by **fikus01** » Tue Sep 04, 2007 9:57 pm

dave walker of emerald = tuning ecu god