Megasquirt owners thread

[datfreak]

STM - its great your going to get a megasquirt, tuning a good ecu is one of the best learning/ rewarding experiences you can do with a car.

I've had a few ms on my na6 - at the moment its a ms2 which i find much easier to tune then the ms1 esp with idle control and mat AfR compensation. But even the ms1 runs rings around the standard na6 ECU.

Once you have the ms even 50% sorted you will never want the air flow meter again. I pulled it apart and removed the air temp sensor. Then tried to sell it on ebay for $20, couldn't sell it after a month so I binned it.

Have a look at my build thread to how I used parts from supercheap auto to replace it with a $20 new pod. It used a 3 inch 45 degree bend alloy pipe and the SCA generic pod. I silicon glued the former air flow meter air temp sensor into the standard black plastic inlet.

Some here will disagree with me but if your staying n/a and have a good wideband like the lc2 you mentioned I wouldn't pay to get it dyno tuned.
Once you have the ignition map sorted(mx5talk members can help explain how to do that), then the MS tune software called 'tunerstudio' has a autotune feature that learns from the wideband and gets the map very close to perfect.
You do have to buy the registered version of tunerstudio to do this but it was only about $80au.- the registration is forever so if you change anything on the car(exhaust, head work etc) you can re-autotune it to correct the map without paying any extra.

If you go turbo do get it tuned by a professional as lean out and detonation on a boosted engine will kill it quickly - I learnt this the hard way as the 'professional' I paid did a terrible job and the pistons melted within a week after getting it tuned.

I'd also get a cheap laptop for tuning. I use a $50 gumtree one that I use for tuning and other greasy 'out in the shed' activities.

Also the vtps is useful but not essential to get a smooth running engine. If you dont get one before the MS you can always get one later. I have one now but didn't run one for over a year - the MS is clever enough to do a good job of the accell enrichment directly from the MAP change.

[StanTheMan]

Ive ordered the MSPnP2 together with USB attachment
The wide-band LC2 is also on its way
I still have a variable TPS from a previous Adaptronic installation. But that ended in disaster because I got the whole shebang & caboodle in one hit without any idea whatsoever

I will get the 26 pin pigtail connector for the options port once the map is good to go to install the Flex fuel sensor.

It is possible to install the wideband to give a narrow band signal so it can be installed as soon as I get it. Ive also found out in the meantime the Bosh LSU 4.9 will fit the standard bung.

I intend to take my time. good chance MS may come in & out a few times. I'd love to get a handle on this.

still deliberating the knock sensor. But cant be a bad thing. But i'll need the options port connector for that.

patchy may be back together again this coming weekend. The following weekend at the latest. Will drive it around a bit before the MS will get installed.

[bartmanftw]

Yes the LC-2 has two configurable outputs. Out of the box one is a simulated narrorwband signal and the other is a 0-5V 7.5-22.23AFR signal.

Not sure how well the knock sensor and flex will work on ms2. The settings for them are quite basic.

[Cus]

I have Tacho trouble!

After about 6200RPM the tacho starts going backwards, fast. by the time I hit 6600 in the log viewer, it's back down at 4000RPM on the actual teacho. The car keeps pulling fine.

MS3 + COPs + batch spark.

Suggestions?

[StanTheMan]

STM - its great your going to get a megasquirt, tuning a good ecu is one of the best learning/ rewarding experiences you can do with a car.

I've had a few ms on my na6 - at the moment its a ms2 which i find much easier to tune then the ms1 esp with idle control and mat AfR compensation. But even the ms1 runs rings around the standard na6 ECU.

Once you have the ms even 50% sorted you will never want the air flow meter again. I pulled it apart and removed the air temp sensor. Then tried to sell it on ebay for $20, couldn't sell it after a month so I binned it.

Have a look at my build thread to how I used parts from supercheap auto to replace it with a $20 new pod. It used a 3 inch 45 degree bend alloy pipe and the SCA generic pod. I silicon glued the former air flow meter air temp sensor into the standard black plastic inlet.

Some here will disagree with me but if your staying n/a and have a good wideband like the lc2 you mentioned I wouldn't pay to get it dyno tuned.
Once you have the ignition map sorted(mx5talk members can help explain how to do that), then the MS tune software called 'tunerstudio' has a autotune feature that learns from the wideband and gets the map very close to perfect.
You do have to buy the registered version of tunerstudio to do this but it was only about $80au.- the registration is forever so if you change anything on the car(exhaust, head work etc) you can re-autotune it to correct the map without paying any extra.

If you go turbo do get it tuned by a professional as lean out and detonation on a boosted engine will kill it quickly - I learnt this the hard way as the 'professional' I paid did a terrible job and the pistons melted within a week after getting it tuned.

I'd also get a cheap laptop for tuning. I use a $50 gumtree one that I use for tuning and other greasy 'out in the shed' activities.

Also the vtps is useful but not essential to get a smooth running engine. If you dont get one before the MS you can always get one later. I have one now but didn't run one for over a year - the MS is clever enough to do a good job of the accell enrichment directly from the MAP change.

Cheers for that . I do have a variable TPS from a previous journey into bigcams & adaptronic. But it was a disaster for me. In hindsight I understand why. Tuning a ECU without a wideband & thinking the auto tune would work makes me roll my eyes now.

If it goes pairshape I'll go to the pro. No plans to go turbo any time soon. However it would be nice to have 2 5vers 1 N/A. 1 Turbo ..... both NA's

[Red_Bullet]

I have Tacho trouble!

After about 6200RPM the tacho starts going backwards, fast. by the time I hit 6600 in the log viewer, it's back down at 4000RPM on the actual teacho. The car keeps pulling fine.

MS3 + COPs + batch spark.

Suggestions?

What value resistor did you use for the pullup? I think I used 1000 ohms. I'm thinking that if you used a resistor with too high an ohmage you might get what you are seeing.

Actually my in dash tacho reads fast, that is it reads higher than the MS log. I would trust the MS log to actually be correct.

[Cus]

What value resistor did you use for the pullup? I think I used 1000 ohms. I'm thinking that if you used a resistor with too high an ohmage you might get what you are seeing.

Actually my in dash tacho reads fast, that is it reads higher than the MS log. I would trust the MS log to actually be correct.

I am, as best as I remember, using a 1k resistor. The other option was a 360ohm one, but I think I opted for the 1k.

It's coming out of tach out on the MS3pro, pulling up to 12v inside the ECU, and then going off into the loom on 2I

I think this is where I've gone wrong, and used two different sets of instructions - 4+5 on the igniter plug are bridged (which I think should make the tacho work) but unless I also have tach out from the coils go to the 4+5 bridge, there's no tacho. As far as I understood it, the MS3 should drive the tacho with 4+5 bridged and 2I on the ECU going to the tach out on the MS3pro.

Here's a video I made my brother-in-law shoot for me today: ('scuse the radio)


The car keeps pulling, but the tacho goes mental... it does seem to come good when I back off though....

[Red_Bullet]

Reading the MS3 Manual

The tachometer feature provides a pulsed output suitable for connecting to a tachometer (rev counter.)
The Tach Out pin will generate a 0-12V signal that will drive most aftermarket tachometers. The stepper
output pins will also supply a 0-12V square wave. Some older tachometers may need additional
work if they are designed to use the pulse from a coil negative terminal or are current dríven.
• Tacho output enabled - enables the feature
• Output on - selects the output pin
• Speed -
– Normal - an output pulse is generated matching each cylinder event. i.e. 4 cylinder engines
have 4 pulses per engine cycle.
– Half speed - output runs at half speed. This can enable a 4-cyl tachometer to be used on
an 8-cyl engine.
The tach output does not currently support other fractional speeds, such as running a 4 cylinder
tachometer on a 6 cylinder engine.
Note that you can select other channels for tach output, but these pulse from floating to ground.
To obtain a 0-12 volt signal from one of these channels, you can wire a 1K resistor from the output to
a switched 12 volt source.
-----------------------------------------------------------------------------------
So the standard tach output on the MS3 Pro is 0-12 volts pulsing. Positive switching. The Mx-5 tacho switches to ground. not compatible. That is why I used the old circuit to run the tacho.

However you can according to the manual assign the tach output to another negative switching output of your choice. You will still need to isolate the two circuits as in the post above, by disconnecting the blk/wht wire from the COPS/Coils.

[Cus]

I ended up sorting it out! (many thanks to bartmanftw for the guidance)



4 + 5 on the above connector are bridged (the ignitor is long gone)

"TACH OUT" on the MS3Pro module goes to 2I on the loom.

No other steps required; ie: don't wire in the "tach out" from the coils, don't do any pull-up mischeif with a resistor, confirmed working all the way to almost 7k.

So the standard tach output on the MS3 Pro is 0-12 volts pulsing. Positive switching. The Mx-5 tacho switches to ground. not compatible. That is why I used the old circuit to run the tacho.

The ecu goes "high" on an ignition event, and the tacho counts the "going low" events as an igniton event, so it does work (the ecu outputs a 12v - 0v square wave) but there will be a slight amount of lag, at worst I'd think it'd be one spark event behind, which if you add in the rest of the inaccuracies of the na6 dash, makes almost no difference to the end result: needles move, driver smiles!

While I had the ECU out of the car I decided to wire in launch control. It turns out Frank's Board already has it wired in, I just needed to:
a) enable it in TS (Digital Input 1)
b) know that having the car in neutral also looks like the clutch is in to the ms, so sitting in my driveway I couldn't get the launch control to turn off. putting it in gear and actually launching works though

[Red_Bullet]

Good that you got it sorted. Is your car an NA6 or NA8? And to confirm, you left the tacho out output on the default "tacho out" driver in Tuner Studio?

[Lokiel]

Good that you got it sorted. Is your car an NA6 or NA8? And to confirm, you left the tacho out output on the default "tacho out" driver in Tuner Studio?

Even better that you posted the solution for others to find (I HATE it when people post problems but DON'T post their solution, if they find one; if you get help from the forum, you should return the favour by posting the concise solution on the forum).

Kudos

[Cus]

Good that you got it sorted. Is your car an NA6 or NA8? And to confirm, you left the tacho out output on the default "tacho out" driver in Tuner Studio?

Mine's NA6

Settings in TS are:

Code: Select all

Tacho Output Enable:  On
Tacho Output On:      Tach Out
Fixed or Variable:    Fixed
Speed:                Normal

Even better that you posted the solution

There are few things more annoying than having a problem, googling for a solution, then finding one person with the same issue, so you read three pages of troubleshooting and then it just ends with "nevermind, fixed it" ... HOW DID YOU FIX IT RANDOM PERSON FROM THE INTERNET? HOWWW?

[StanTheMan]

There is perhaps a stigma about noobs asking question
Read more
Your in over your head.

So Megasquirt has become secret tuners business.

And a lot of people think "I had to figure it out myself. Everyone else can figure it out themselves as well."

This is detrimental to these type of forums.

Or when a expert comes along." No not going to work. But without saying why it will not work. They may as well not have posted.

/rant

[Red_Bullet]

It seems to me there may be more than one way to get the tacho working correctly. I've got mine working, so has Cus. With different methods. Good. There is likely a third way, which I'm thinking may well be better. But I'm not about to go and spend time testing it, got better things to do with my time.

Edit

I don't think that Megasquirt has become secret tuners business, not at all. The MS manual is very detailed and accurate. It is long and detailed as necessitated by all the functions it can do. There are a lot of options which a new-comer can find quite daunting. Armed with the MS manual AND the schematic of the car, it's not really so difficult. But it is time consuming, although very educational/enlightening at the same time.

[Red_Bullet]

Anyway, for clarification, here is quickly drawn up "mud map" schematic. Hope this helps. A picture paints a thousand words. This is for a 1994 NA8.

Tacho circuit by Keith Wade, on Flickr