Tuning MegaSquirt for 998 NA
Turbo Mini Forums

Following on from my build thread - http://www.turbominis.co.uk/forums/index.php?p=vt&tid=334028

I have spent the last few days on and off making small changes to the Megasquirt tune, specifically around the Injection timing and Req_fuel values.
I have now got a tune which THINK is somewhere near good, or at least on the right track...

Edited by Graham T on 16th Mar, 2010.

’77 Clubman build thread
http://www.turbominis.co.uk/forums/index.php?p=vt&tid=618189

Siamese 5 port EFI testing
http://www.turbominis.co.uk/forums/index.php?p=vt&tid=611675

Looking good, once you get them as close as possible just increase the fuel via the VE table to slightly richen it up and jobs a goodun!

How are you finding it to drive?

Although it's only an NA 998, it is Unreal to drive, in comparison to a week ago. Without knowing any power/torque figures, before or now, I'm convinced that it pulls better, right from tick over. much smoother acceleration also.
However, how much is attributed to the Ingintion side and how much to the EFI, I don't know. I drove for a few days with Ignition only and that made the drive much better.

The only downer at the moment is tick over. I got over the cold start issue, but cold tick over is very lumpy. outers way to lean, so I'm playing with the inj timing load bins to accomodate this. I hope.

I have hot tick over at around 1300rpm, again lower that this and it's lumpy, but again, I think its just down to inj timing. Hot tick over AFR's are 10 outers and 7.5 (probably more) inners.

’77 Clubman build thread
http://www.turbominis.co.uk/forums/index.php?p=vt&tid=618189

Siamese 5 port EFI testing
http://www.turbominis.co.uk/forums/index.php?p=vt&tid=611675

Moving forward for sure...

On both plots the outer wideband seems a bit noisy but the AFRs seem well matched on the first plot but begin to deviate on the second one later on (I assume the second Megatune plot runs for a longer time ???) ie, at the highest RPM.

If I've read all the colours right it seems you just need to offset the timing slightly more at high RPMs or, as Sturgeo says, now attack the VE tables.

I'd leave the VE tables until last as you really shouldn't have any issues with pulses overlapping by moving the timing a bit more with the injectors you are using.

Schrödinger's cat - so which one am I ???

Schrödinger's cat - so which one am I ???

Yes, The second graph is a slightly longer time frame, so shows higher RPM. I also noticed the greater distance between AFR's at the higher RPM's.
I've just changed the INj Timing and Run again. I think they are better. I'll look more in depth later.

I actually advance Inj 1, but I'm not sure yet whether advancing or retarding will get them closer together... I would have expected to have to retard it, else I am getting the pulse for the outers further into the inner cylinder inlet valve open window.

Just a big learning curve.

What could cause the noise on the Lamda sensor?

’77 Clubman build thread
http://www.turbominis.co.uk/forums/index.php?p=vt&tid=618189

Siamese 5 port EFI testing
http://www.turbominis.co.uk/forums/index.php?p=vt&tid=611675

Re the pulse timing, always bear in mind transit time.

Big learning curve ???? Yes !!! And all my work has been on a stationary engine or the JimStim so far. Just look at what Paul and Sturgeo went through...

The Lambda noise is usually either the sensor cable too near something like an HT lead or poor grounding on that controller.

Schrödinger's cat - so which one am I ???

I'll move the wide band controller. It's next to the fuse box that supplies the rest of the car. Silly place, but I ran out of room. It was one of the "refinements" I needed to do.
And check the solder joint on it's gound wire.

’77 Clubman build thread
http://www.turbominis.co.uk/forums/index.php?p=vt&tid=618189

Siamese 5 port EFI testing
http://www.turbominis.co.uk/forums/index.php?p=vt&tid=611675

That is looking good. It took me a couple of years to get them that close.

You do need to richen it up though before you make too many more injection timing changes. This is because the affect of wall wetting gets greater with richer mixtures.

If you just add 10% to the top two lines of the VE map, then that should do it for now.

Whether you need to advance or retard to get them closer together is a matter of trial and error because it depends where you started from.

Generally, we found that after setting idle to give equal AFRs, then involved advanced timing at higher revs and at lower MAP i.e. the highest advance figure is at WOT at maximum revs. With spray injectors, I would not expect the spread of timing to be much more tham 40-50 degrees.

Saul Bellow - "A great deal of intelligence can be invested in ignorance when the need for illusion is deep."
Stephen Hawking - "The greatest enemy of knowledge is not ignorance, it is the illusion of knowledge."

Another set back. I think...

It appears my second trigger is not working.
Sometimes I start up and it runs up fine, but mostly I'm getting very rough running. Switch off and restart a few times and eventually it runs fine, so I am guessing it's not getting a signal from the second trigger?

Is there any way to test this without the use of a scope? ie should I get a visible voltage from the signal wire on say, a volt meter? I'm not sure what sort of signal should be output from it.
The hall sensor is the Siemens HKZ101, as Per Paul S's

Also, if I had set up the timing tables when the engine was running 360deg out, so the ecu seeing number 4 cylinder as number 1, could I achieve the results posted above? I ask, because no matter what I do, I cannot get AFR's to match at tickover. I can get the outers down to 14.5 AFR, but the inners the best I can achieve is 10, then the engine starts "hunting".. and I cannot get a better run than that posted early.

’77 Clubman build thread
http://www.turbominis.co.uk/forums/index.php?p=vt&tid=618189

Siamese 5 port EFI testing
http://www.turbominis.co.uk/forums/index.php?p=vt&tid=611675

Your diagnosis is sound, unless you've accidentally put the settings wrong in the msq so it's not expecting the second trigger.

Can't really test with a DVM as it's a short square pulse but you can connect an LED and series resistor and look for it flashing when cranking. BUT you must disconnect that wire from the MS first as the opto-isolator chip inside is effectively an LED and LEDs don't current share, ie, you won't know which one is going to "flash".

As an aside, is the Hall switch getting a suitable power supply ???

Not sure about the last one, I would have though 360 out is the same as the 50/50 chance without a cam pulse, ie, good or very rough, as it's the same as the cam pulse being 360 out.

Schrödinger's cat - so which one am I ???

I tested the input and I'm getting around 12.5V.

I'll test with an LED. I assume a 1k resistor in series is fine for this?

I believe the trigger wheel settings are good:

’77 Clubman build thread
http://www.turbominis.co.uk/forums/index.php?p=vt&tid=618189

Siamese 5 port EFI testing
http://www.turbominis.co.uk/forums/index.php?p=vt&tid=611675

Just thought.
I tested the input with ingition on only, not cranking.

If I make any change whilst the engine is running, say an IAC step setting, then burn to the ECU, The engine goes rough and I have to restart. So does any burn reset the ecu. Hence the ecu picks up its correct phasing whilst running.. I'll go check voltage to the hall sensor when cranking.

Edited by Graham T on 21st Mar, 2010.

’77 Clubman build thread
http://www.turbominis.co.uk/forums/index.php?p=vt&tid=618189

Siamese 5 port EFI testing
http://www.turbominis.co.uk/forums/index.php?p=vt&tid=611675

So far as I'm aware, trigger wheel settings should be "second trigger active on" EITHER rising OR falling depending on where your switch switches on and off (I have mine on rising edge to get it the set margin away from the 36:1 missing tooth as the falling edge was quite close).

I'm not quite sure why "rising and falling" exists but presumably it creates two pulses instead of one ???

A 1k resistor will be fine but ideally use the same value as the one you have in the MS circuit to the opto-isolator.

Schrödinger's cat - so which one am I ???

Second question, no the ones in red need a reboot (although some seem to work without) and there are several settings you must NEVER change with the engine running....

Schrödinger's cat - so which one am I ???

Yes, second trigger should be set to rising edge.

At the moment, your cam wheel setup is cancelling itself out.

Saul Bellow - "A great deal of intelligence can be invested in ignorance when the need for illusion is deep."
Stephen Hawking - "The greatest enemy of knowledge is not ignorance, it is the illusion of knowledge."

I have set the second trigger to rising edge (and tried falling edge, just for grins). No joy.

Checked the input voltage to Hall sensor during cranking. It stays as per voltage without cranking, but ignition on.

Attached an LED and 470r resistor to the signal wire (green wire) of the hall sensor and to ground. (removing second trigger input wire from MS). LED works against input voltage.

No flashing LED...

I have a second hall sensor that I will install tomorrow and test. Is there anything else that immediately springs to mind that could be wrong?

’77 Clubman build thread
http://www.turbominis.co.uk/forums/index.php?p=vt&tid=618189

Siamese 5 port EFI testing
http://www.turbominis.co.uk/forums/index.php?p=vt&tid=611675

You can have a look at the composite logger. Select the diagnostics tab in TunerStudio and you will have a graph of what MS is seeing from your two tach inputs.

You can capture the screen and post it here.

Jean

http://www.jbperf.com/

I don't know if this will help, but this thread details how I set up and tested my cam sensor:

http://www.turbominis.co.uk/forums/index.p...id=201921&fr=25

Saul Bellow - "A great deal of intelligence can be invested in ignorance when the need for illusion is deep."
Stephen Hawking - "The greatest enemy of knowledge is not ignorance, it is the illusion of knowledge."

If the test LED/resistor doesn't flash when cranking (but lights when connected to 12V) then either,
The hall switch has failed,
Something mechanical has moved, ie, the gap,
The test circuit is not a valid representation of its operation.

The thread Paul quotes reminds me of why I dislike Hall switches (or anything with an open collector output that relies on the power supply and pull-up resistors). Can you do a sketch of how exactly you have it wired for your LED test ??? (just on paper, scan it and post it).

Schrödinger's cat - so which one am I ???

Jean, Heres a screen dump of the composite logger




Paul, thanks for the link. I'll read this through.

Rod, I have no scanner at home, So I will sort in the morning before I start work.

thanks all

’77 Clubman build thread
http://www.turbominis.co.uk/forums/index.php?p=vt&tid=618189

Siamese 5 port EFI testing
http://www.turbominis.co.uk/forums/index.php?p=vt&tid=611675

Graham,

There's definitely a problem because there is no cam trigger in this log. There should be a green graph above the blue with pulses when the cam signal occurs. Have look at this:http: //www.msextra.com/doc/ms2extra/MS2-Extra_tooth_logger.html.

So you either have a bad sensor/input or there is a misconfiguration somewhere.

Jean

http://www.jbperf.com/

This is what it should look like:



Jean

http://www.jbperf.com/

After reading the thread Paul posted a link to earlier, I now have a better understanding of the hall sensor and how it works.

I can see lots of shaking of heads at this point, but I thought the sensor wire (green) from the hall sensor supplied a voltage, not went to ground. Hence why I connected it up like this yesterday:





So, if I use:





Red to 12v Ignition
Black to ground
yellow to Hall (Green wire)
L7805 5v regulator used


Should that work for testing the hall sensor?

I will also try some of the tests in Paul’s thread, once the hall switch is eliminated...

’77 Clubman build thread
http://www.turbominis.co.uk/forums/index.php?p=vt&tid=618189

Siamese 5 port EFI testing
http://www.turbominis.co.uk/forums/index.php?p=vt&tid=611675

Yes, the sketch is "wrong" but the test circuit on the breadboard is correct and should match what is inside your MS2 box if you wired it as per Paul's original drawing. Just touch your yellow wire to ground (black) first to check the LED is the right way around

Schrödinger's cat - so which one am I ???