Cus' NA6

[Cus]

It seems Nevyn was on the money.

I have spark.

I seem to have no fuel.

I can *small* fuel, but the plugs are dry as a dead dingo's, maybe it's placebo fuel.

Next stop: mutimeter poking and maybe some of Jack's Stages of Grief:

[Cus]

I have Fuel! The "Active Fuel" circuit on the adapter board seems to have been the culprit (ie; I removed it, and now we have fuel)

And, for the first time since I've owned the car, I can hear the fuel pump when the key goes to "on" - and it even started once!

Now it just turns over, backfires and dies, and now the megasquirt tells me the battery is flat.... Mr Neighborman has loaned me a battery charger, progress continues.

[Cus]

IT'S ALLIIIIIVVVEEEEE!!!!!

This video explains most of what I was up to this morning. It does not include about 6 hours of talking sh*t with Mr Neighborman, checking the timing, then chasing my tail on the fuel.



First drive was unexciting, to the roundabout and back. Second drive was slightly more exciting, gave it a 1st -> 2nd booting, only to have the car start idling in 2nd and not make any power, at all whatsoever. Pulled up and popped the bonnet, my excellent wiring in the diag connector had failed me, the +5v to the MAP came off. Put it back on, continued on my merry way, making note to keep out of it until I fix the wiring.

I don't have the VTPS attached to the car yet, it's plugged in, but not on the throttle body. Running in MAPdot mode at the moment, and it's a bit of a pig. Stalled it reversing out the driveway and everything! Once you get "into it" it's fine,but at low RPM or big throttle movements, things don't always go as expected. I still need to do some hardware adjustments to get the new TPS on the car (tap holes, make a spacer and/or cut the shaft down) but thanks to how everything is packed into that part of the engine bay, I need to drop the coolant to remove the radiator hose to get the intake hose out of the way so I can get to the TB.... it will be fun!

Tomorrow I'll clean up the wiring so it's 900% less dodgy, then run some wires for seq injection, then test it, then ... NOT install the COPS, because I just realised I have no way of mounting it. To the OMGPham Website!

Then we do the cops + seq spark.

Pretty chuffed with how this has worked out so far, most of this has been a matter of reading far too many forum posts, getting confused, working out a solution, and then getting confused again. Now it's actually in the car and works I can start learning about tuning... the fun never stops!

[smy0003]

Nice work Cus!
It's quite an amazing feeling driving for the first time on a standalone ecu.
Still very, very impressed by your beard.

Sent from my LG-H815 using Tapatalk

[speed]

1000 points for percevering!

[Cus]

Thanks gents!

I may need to reassess my goal-setting timeframes, or work faster. Most of the things I said I'd do yesterday, I didn't. I did put plugs on wires in the engine bay though, so now I can change gears at higher RPMs without things randomly unplugging themselves....

I know that putting an ECU in an MX5 is something of a non-event in the grand scheme of things, but it's a computer, and I like computers!

Especially ones that log data, and then allow me to review that data, change some inputs, and compare some new data.

There is going to be such nerd, so excitement, many maps, very tables, an so on....



This is the 1.6 basemap from the DIYAutoTune website, with a whole bunch of autotune run on it. Basically everything from 4300 down has been hit enough times that auto-tune has stopped adjusting it more than half a point in any direction, which is cool.

What isn't cool is just how doughy it feels. MAF delete added a whole bunch of induction noise, which makes it sound faster, but it's really lazy. From looking at other spark maps on the intertubes (because they're all going to be accurate and safe....) +5 degrees of timing would be a good start, 10 degrees could do a lot of good (or, more likely, break sh*t) ... I'll play with that later, like after I work out how to do knock detection. It's not running hugely rich in areas I hit in normal driving, so that's a good start.
(side note, this is the first and only time I'd hit 6500RPM since the ECU install, it seemed to take forever to get there!)

The adventure continues....

[Cus]

Day 8 of the MegaSquirt MegaAdventure.

All this data is getting to me. I have a problem. So many logs, so many graphs.

I even rebuilt my fuel usage spreadsheet (the version I had backed up had about 6 fills in it, way back when the odomoeter said 241000.

Thanks to this new data, I know my NSW/QLD trip earlier in the year netted me low 7's per 100km - I even managed a 6.82L/100k at one point.

I have put two tanks of fuel though the MegaSquirt, and travelled 716Kilometers. 9.5L/100k and 8.98L/100k - not the worst numbers I've had, but definitely the worst back-to-back. This has included a lot of time dialing in Closed-Loop Idle. I think I have it nailed. There are some oscillations that appear under some circumstances, but looking back at the logs I took from tonight, I suspect they were caused by having Closed-Loop EGO correction enabled, I've since turned it back off because it wasn't setup, and was doing stupid sh!t.

I have watched probably an hour worth of videos explaining PID control systems. I think I understand it now. More Idle tuning will let me know.

I've auto-tuned the VE table to death, one drive it takes out .2 from the table, the next drive it'll put it back in.

The coolant is not getting up to tempreature while the car is moving, I suspect I went too far solving my overheating issue last summer. If I sit in the driveway fluffing about with the Idle / AC Idle-up it will actually get up to temp and the fans will come on. Otherwise it seems to wobble around in the mid-to-high 70's.

Today I played fabricator. It was amazing. ...ish. I've decided I'm more "persistent" than "fabricator".

COPS BRACKETS!

Step one: CAD.


Here is my pseudo cam cover modelling the COPS.


Counter-sunk holes for the bolts, because *nobody* had the ones I was looking for. The keen observer will see I started filling down the head of one of the bolts. That lasted about 5 minutes before deciding to counter-sink the bolts.


Step four: Done.


The car isn't actually wired up to use them yet, maybe tomorrow, maybe next week. I need to run some thinner wires out through the firewall, the ones I've got run out are about 1mm too thick to fit in the back of the OEM ECU plug.

[Cus]

Well, this explains the puddle of coolant under the car this morning. Apparently I was a little rough with the heater return pipe when I was pulling the exhaust off. Oops...

Coolant System: 10 - Cus: 0



A new o-ring is on the way, and a cas o-ring as well, just while I'm in the mood for changing leaky o-rings.

Before:


While it's off it's being sanded and painted blaaacck. At least this will give me plenty of time to wire up sequential injection, and my COPS.

I swapped the COPS bolts out with ones 10mm shorter, they could be another 5mm shorter again, but Bunnings is a long walk from here

[gslender]

What isn't cool is just how doughy it feels. MAF delete added a whole bunch of induction noise, which makes it sound faster, but it's really lazy. From looking at other spark maps on the intertubes (because they're all going to be accurate and safe....) +5 degrees of timing would be a good start, 10 degrees could do a lot of good (or, more likely, break sh*t) ... I'll play with that later, like after I work out how to do knock detection. It's not running hugely rich in areas I hit in normal driving, so that's a good start.

Your spark map is woefully too safe, and when you change the spark you'll need to retune the VE table again. This is where I'd start for a more approporiate spark table for a MX5

[Cus]

Thanks Grant! That table has a good 8 - 9 degrees everywhere at 100kPa over the DIY base map, although the DIY map has about 3 - 5 degrees more timing below 50kPa, I'll smoosh 'em together tomorrow and see what happens

As an aside; TS Projects work really well in git - reading a commit log is way easier than trying to remember what you'd changed when you saved "coldstart4.msq" - and you get dash-backups as a bonus! (.gitignore the restorePoints/ dir though, that just makes a mess!)

[datfreak]

A reminder to change your dwell settings for the cops setup, so it doesn't kill one of them.

I dont have a na6 ignition table on this pc but my WOTS (90-100kpa) above 3500rpm were 38 degrees. Im running 98 fuel with this much advance.

[gslender]

Some folks have stated that the stock ecu is as much as 40 deg adv in the spark curves.


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[Cus]

So, this morning I thought to myself "I'll just write a script that converts that 12x12 table into a 16x16 table and works out the values in the middle"

If you ever find yourself having thoughts like that, stop them immediately. They are not good thoughts.

I'm fairly certain my brain has turned to mush and a large percentage of it has dribbled out of my ear. I'm fine with this for the following reason:

Well, you see, Norm, it’s like this. A herd of buffalo can only move as fast as the slowest buffalo. And when the herd is hunted, it’s the slowest and weakest ones at the back that are killed first. This natural selection is good for the herd as a whole, because the general speed and health of the whole group keeps improving by the regular killing of the weakest members.In much the same way, the human brain can only operate as fast as the slowest brain cells. Now, as we know, excessive intake of alcohol kills brain cells. But naturally, it attacks the slowest and weakest brain cells first. In this way, regular consumption of beer eliminates the weaker brain cells, making the brain a faster and more efficient machine.

And that, Norm, is why you always feel smarter after a few beers.

On the face of it, it seems easy, calculate the slope a-la highschool maths, plug that value in, and ka-blammo, it's done.

Except it's not that easy. We actually know the values of the slopes we want (ie; RPM and kPa values) what we want to find out is the *other* value, which is the value of the intersections of the slopes? I think? I don't know man, it's all a bit heavy. And sometimes there's three 'old map' bins between one 'new map' bin, and sometimes one 'old map' bin needs to cover a couple of 'new map' bins. I seriously considered a giant pre-compute table of every RPM and kPa increment, it would have only been 1Gb or so....

I asked Droo, he didn't really know either, but he mentioned interpolation, and it put me on the path of finding the equation for Bilinear Interpolation, which is almost exactly what we want. I say "almost exactly", because Bicubic Interpolation will be "nicer" - I need to find the equation for that (or; a version I can understand enough to turn into code), but Bilinear Interpolation will allow me to write the rest of the script. Having the equation is the hard part, the "easy" part is comparing the values of the RPM and kPa bins and seeing which corresponding RPM/kPa bins we need to interpolate from, which is easy, if you like nested for loops and if statements and gimp suits.

The best explanation for Bilinear and Bicubic Interpolation is in the top two pictures on the right of this article (Treat it like a porn magazine; ignore the words, look at the pictures - lest thy brain melt and runneth forth from thy ears): https://en.wikipedia.org/wiki/Bicubic_interpolation

Unless... *Casts Summon Grant* Do you happen to know off the top of your head what sort of interpolation the MS uses internally to compute the values between cells? (Bilinear or Bicubic, or "something else"?)

Either way; here's a thing: http://imgur.com/OmR6gjg


Green matches an RPM Column from the "original" map.
Yellow matches a kPa row from the "original" map.
Blue is interpolated RPM + kPA.
Red is a copy of whatever is to the left.

There's still heaps to do. Like make the bottom table actually update when you change the top one, at the moment it's all just hard-coded in so I could test the maths and the loops and the gimp suits. With a little bit of photo-shoppery the plan is to be able to upload one of the screenshots, have OCR read the table, present it for verification, allow an edit, and then give you a 12x12 or 16x16 table from a 12x12 or 16x16 for a given set of RPM/kPa bins - although at the moment it just does 12x12 -> 16x16, and none of that fancy stuff works.

And I want a "map difference" mode, so it will show me which partsof a "new" map a higher/lower than an existing one. Being able to upload .msq's and have them spat back out with the new map inside it will also be cool. None of that is happening today though...

A reminder to change your dwell settings for the cops setup, so it doesn't kill one of them.

Ta! Thanks to the contents of this post, I didn't actually put the COPS on today... Tomorrow, maybe? (Car isn't running anyway, no coolant due to the O-Ring a couple of posts back, so I'm not in any real hurry)

Oh yeah, after-shot of the painted pipe, because arts and crafts are fun:

I dont have a na6 ignition table on this pc but my WOTS (90-100kpa) above 3500rpm were 38 degrees. Im running 98 fuel with this much advance.

I'll pester you for a look at this sometime in the future ;)

Some folks have stated that the stock ecu is as much as 40 deg adv in the spark curves.

You've probably seen this, but here's a linky-loo: http://www.miataturbo.net/megasquirt-18 ... 662/page2/ looks like all of that advance is in the vacuum/decel bins.


Time to rest my brain I think...

[Ice88]

That will only work providing values are linear. VE is not linear

[NitroDann]

Tunerstudios can do this for you can't it.

Also, sounds like.something 30 minutes on a dyno would fix..