Page 1 of 1
Megasquirt MS3Pro Mini ECU
Posted: Sat May 04, 2024 11:18 am
by Hugues
I finally decided to buy an ECU for my Pinz, first to monitor its advance and exhaust gas,
then when everything is stable i will drive the advance with it instead of my distributor,
maybe one day upgrade to EFI but that's not sure yet,
I bought this gear from
https://www.diyautotune.com/product/ms3 ... w-harness/
MS3Pro Mini Standalone Engine Management System w/ Harness
Crankshaft / Camshaft Position Sensor - Hall Effect tab mount
Innovate LC-2 Digital Wideband Controller with Sensor - 38770
GM IAT Sensor with open element & pigtail
GM Closed Element CLT/Oil Temperature Sensor with Pigtail
I still need to order the smart coil module:
https://www.diyautotune.com/product/ign ... coil-pack/
I installed it today and connected it to my laptop,
the only data i have for now is Manifold Air Pressure, as can be seen in below video,
I will install a trigger wheel on the crankshaft pulley, wideband O2 sensor and temp sensor.
I intended to buy the Speeduino initially but it was either out of stock or the shop did not reply to my mails,
Carl at diyautotune was pretty good to reply to my questions,
https://youtu.be/x-Jh8YTtFbI?si=HIgRGugz6zM47hMs

- ms3pro mini ecu.jpg (312.96 KiB) Viewed 9589 times
Re: Megasquirt MS3Pro Mini ECU
Posted: Sun May 12, 2024 12:41 pm
by Hugues
Installed the O2 sensor and the 36/1 toothed wheel this long week-end
With the O2 sensor, already saw that my idle fuel mixture was too rich, so adjusted the carbs live with the O2 sensor, no more guessing for me.
short video here:
https://www.youtube.com/watch?v=sEBzG3iG8Yo

- IMG_20240511_144557.jpg (609.4 KiB) Viewed 9438 times
Re: Megasquirt MS3Pro Mini ECU
Posted: Wed May 15, 2024 9:20 am
by rmel
Curious.... Where did you install the O2 sensor?
Re: Megasquirt MS3Pro Mini ECU
Posted: Wed May 15, 2024 12:10 pm
by Hugues
rmel wrote: Wed May 15, 2024 9:20 am
Curious.... Where did you install the O2 sensor?
Yes good question,
On the green circle below.
Right on top of that pipe, 12 o'clock,
Had to be at least 60cm away from engine exit.
And this way I measure the combustion of both carbs.
Had to remove the exhaust between the engine and the heat exchanger to weld the bung, a bit of a pain.

- o2 sensor.jpg (269.89 KiB) Viewed 9386 times
Re: Megasquirt MS3Pro Mini ECU
Posted: Mon Jun 03, 2024 1:03 pm
by Hugues
Received my new coil today, to use with my ECU to control advance.
Little connector problem. I have the civil ignition spark plug cables, on the distributor side, it's a male connector, see 1st picture below.
But on my new coil there is a different connector. The rubber cap fits onto it, but inside it's not a female connector but a male connector.
Technically the tip of my current male connector would touch that male connector pin on the coil, but that does not sound like a good idea.
Anyone knows what kind of connector is this on the coil side ? I could buy or build an adapter, but not sure what to order.
This is the coil I bought:
https://en.ridex.eu/product/8055482
male connector on the spark plug cable

- male connector spark plug cable.jpg (604.84 KiB) Viewed 9231 times
coil side, male connector

- male connector coil side.jpg (545.64 KiB) Viewed 9231 times
Re: Megasquirt MS3Pro Mini ECU
Posted: Fri Jun 14, 2024 10:06 pm
by VinceAtReal4x4s
M4 connector?
Re: Megasquirt MS3Pro Mini ECU
Posted: Sat Jun 15, 2024 1:52 am
by Tjerk
Re: Megasquirt MS3Pro Mini ECU
Posted: Sun Jun 23, 2024 11:25 am
by Hugues
Tested the timing advance from my Megasquirt ECU for the first time today,
No major issue, advance is ok at idle and around 2'000 rpm,
I'm using the Pinz manual advance curve for now,
once i've got everything under control, i'll explore a bit the other advance functions, taking into account engine load for example.
a bit more info here:
https://youtu.be/ubd-Mtm6sg4?t=101
Re: Megasquirt MS3Pro Mini ECU
Posted: Mon Jun 24, 2024 8:27 am
by Hugues
So my idle advance was stable so I decided to give it a try.
I first built the advance table based on the Pinzgauer manual, so purely based on rpm, not taking into account engine load, red corridor on bar chart below.
It ran ok but when starting to go uphill at mid rpm i had a bit of backfiring through the air intake, so probably firing too late.
So i then adapted my advance table to take into account load, but always stay with the Pinz manual red corridor.
Backfiring is now gone. Only impression is that power could be improved under load going uphill.
Should I push my advance beyond 28 degrees in these conditions (under load going uphill) ? 32 degrees maybe at first to see if it makes any difference ?
Running unleaded 95, at around 600m altiitude / ~2'000 ft
I show the advance chart shared by @rmel in this thread:
viewtopic.php?p=93655#p93655
edit: after a bit of reading, i might have modified my advance table in the wrong way, looks like for a specific rpm, say 2000, as engine load increases (less vacuum), advance should decrease. My table below would be wrong then...
My current advance table:

- advance map.jpg (296.36 KiB) Viewed 8830 times
advance chart used by rmel , under load

- advance rmel.png (296.04 KiB) Viewed 8830 times
Re: Megasquirt MS3Pro Mini ECU
Posted: Wed Jul 31, 2024 12:10 pm
by Hugues
Just to update this thread if ever someone goes the same way,
This is the ignition table i've been running with these past 2-3 weeks, looks good, could be tuned better, but good enough for now

- ignition table.jpg (315.11 KiB) Viewed 8007 times
Re: Megasquirt MS3Pro Mini ECU
Posted: Thu Mar 12, 2026 11:00 am
by fpvmustang
Nice work.
Diyautotune is great I have 3 vehicles running ms3.
Re: Megasquirt MS3Pro Mini ECU
Posted: Thu Mar 12, 2026 2:40 pm
by Hugues
thanks
been running on this ECU ever since my post,
i have implemented a fuel cutoff system when engine breaking, using ECU and a relay to close the carbs solenoid,
Beauty is, if ECU fails or some of its components, i can still switch to pure mechanical distributor, no electronic, would take 15min.