NA6 and custom ECU plans

[noisymime]

Finally all mounted up properly and neat rather than as a mess in my footwell


Pretty happy with how things are all running now, enough to call it 'complete' in its current configuration.
Tossing up now between whether I pause for a while and actually enjoy the car or start pulling bits off to fit the ITBs haha

[smy0003]

Pfft, who has time to enjoy things. Start pulling things apart!

Sent from my LG-H815 using Tapatalk

[noisymime]

Pfft, who has time to enjoy things. Start pulling things apart!

I've had this thing 11 months and I think this was maybe the 4th weekend of fun time. But you make a good point!

[datfreak]

Great project - just read this thread and some links on the speeduino forums.

Very cool stuff - I like how it:
Uses tunerstudio
the cpus are inexpensive and plentiful
The 0.4 main board doesnt look too hard to solder and assemble.
your board to mx5 plug connector is neat
is inexpensive


I bought a older megasquirt 3.57 ms1 pnp (i've got two mspnps now- one on car and a spare) as I personally could not justify the cost of a new ms2 or ms3 as I didn't need the the extra features -all I needed was:

remove airflow meter - ecu with map
programmable spark and fuel maps that are accurate - enables decent WOT AFRs / engine flow mods / e85 / turbo
able to convert to cops or any aftermarket coils ie dwell adjustment
decent idle control - icv and afr
decent ase / warmup / acell and decell (both map and tps) settings and processing.
Works nice with lc2 wideband.

The speeduino looks to cover all this so should be a good choice for 80% of mx5 owners. Prove its as reliable as a megasquirt and your on a winner.

Will your kit include the ecu connector that is soldered onto your board? and the box?

How did you handle the fuel pump control? Like the megasquirt with the IG circuit with the fuse removed?

following

[noisymime]

That's pretty much been my thinking all along. It'll never compete with MS3 or anything, but from what i've seen a lot of people don't need all the features it offers anyway. Solid fuel and spark control, ability to remove the AFM and add a wideband plus something that's relatively easy to fit is what a lot of people seem to be after. There's no reason you should need to pay more than $300 (at most) for an ECU that does all that.

I'm currently working on the next revision of the board that is designed to be much more friendly for assembling in volume. Purely for my own ease of testing I'll get the first batch of these done with a 48-pin connector on it, so it would plug directly into without even the adapter board. If there's any interest I'll see about selling these. No commitment on price yet, but expect somewhere under $250 with the connector, case, MAP etc.

[noisymime]

Ohh and with the fuel pump thing, this has me slightly confused because I'm not doing anything with it at all. My fuel pump simply comes on when the ignition is turned on with no changes anywhere else.

I've double checked and its definitely not jumped in the diagnostic box and the fuse seems to be in place. It just... works.

I've been meaning to research this a bit more, but because its something that isn't actually a problem its never found its way up the TODO list

[93_Clubman]

Perhaps datfreak's referring to the NA6 AFM safety feature of cutting fuel when no air flow is detected. Circumventing the safety feature requires a jumper between pins FC & E1 in the plug connecting to the AFM.

Miata Performance Handbook by Norm Garrett shows the following looking from left to right facing the male plug on the AFM:

FC = fuel pump lead
E1 = fuel pump ground
E2 = ground
VC = +5 volts
E2 = ground
VS = air flow signal
THAA = air temp signal

By way of confirmation, the male plug on the AFM in the diagram shows two ridges at the top & three ridges at the bottom providing oneway fitting. Unfortunately no wire colours are mentioned, but i'm sure russellb has posted a wirIng & ecu connector block diagram a few times.

[datfreak]

yeah - After you remove the air flow meter you will know what I'm talking about regarding the fuel pump. The engine will not run.

With a na6 the fuel pump is controlled:
1/ firstly by the starter motor circuit - ie when the key is turned to the start position the pump relay starts.
2/ Then by the air flow meter. So if no air is flowing the pump stops. think flipped or crashed mx5, this prevents the fuel to continue pumping into a broken fuel injection circuit

What the megasquirt does is send a +12 up the starter pin (mauve or purple if I remember correctly) to trigger the fuel pump relay while the engine is running.
This does require the IG fuse in the engine bay to be removed - in early megasquirts failure to remove this fuse caused the pump transistor to burn out.(in the ms board)

$250 does seem a good price for a stand alone ecu that potentially could control a n/a or boosted mx5. I like soldering but some others may want a ready to go option.

Will a IDE cable wire gauge be ok to run injectors/ ignition etc? Not crazy high current but ide is just data cable.

[datfreak]

Hows the ecu project going?

[noisymime]

Not an awful lot to report, at least not on my MX5. The car is driving perfectly in its current form and I'm really just spending a bit of time enjoying it at the moment
Cold starts could use a bit of work, but that's just all in the tune, the code itself seems fine. I will get around to putting the ITBs on at some point, I have all the parts sitting there except 1 gasket, but while the weather is good I'm struggling to find the motivation to take it off the road

The project itself is going great guns though! Steady stream of new members, about 30 different engines now running and a reasonable number of regularly dríven vehicles. A couple of guys working on V8s at the moment, so that'll be another nice milestone to tick off when they're running.

I've been putting in a lot of time on the hardware designs lately. The 'Pro' version board is taking a bit longer than I'd hoped, but mostly because I've done new revisions of the existing boards first. I'm 95% sure that I will be doing a 48-pin plug and play version of the Pro as the first run, mainly so I can plug it straight into my car and test it out. These Pro boards will come fully assembled and currently aiming for somewhere around the $150 USD mark. Might have the first batch of these ready by mid-year if things go to plan.

[noisymime]

Might not be pretty, but the SLC Free 4.9 wbo2 is proving to be a solid little unit. Can highly recommend it if you're a DIY type person and looking to save a few $$s

[noisymime]

OK, has taken quite a bit longer than I'd first hoped, but the design for the MX5 PNP board is now complete! I'll be sending off a test batch for printing within a week or so and will test after that. The plan remains to be able to offer these as a fully assembled package at somewhere around the $150 USD mark, but the timing will all depend on how the testing goes and the costing is very much yet to be confirmed.

Around the fuel pump, I've included 2 options, one using the ST_Sig line, similar to the megasquirt PNP, the other is an output to the AFM connector where it can be bridged, so either way will work there.

[93_Clubman]

Congrats & definitely interested.

[speed]

Well done!

[noisymime]

OK, the MX5 PNP board has taken a bit of a back seat lately due to other developments on the project, but I finally put together the 2nd testing board this weekend. Will be doing the bench testing over the next week and assuming no issues it'll be going onto the car after that.