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Hi guys. I've been working on my NB the last weeks and I think that part of my cranking problems were related to the Trigger Edge.

Seems that my Speeduino detects better the Crank and Cam signal when I select the Leading option.

A couple of days ago it was imposaible to start the engine and when I swapped from Trailing to Leading the engine started. Since I did It my engine starts on the first attempt, not as quick as the oem ecu but much better than before.

Also I've checkes on some stock maps, like the one for the ME221 ecu and also uses Leading.

I'm the only one that feels that Leading works better thab Trailing?

PD: My engine is a 1.8 VVT BP3Z.
Ed, this answer is directed at everyone with all sensor types. Test your setup. Leading or trailing may be different with various setups, as the sensor type and the input conditioner (if used) can invert that signal, causing Speeduino to think it's leading but registers high or low signal as trailing or vice-versa. Also, the polarity of the signal is important, as that determines which edge/end of the current tooth or slot is considered the correct signal. Along with that, if the 'wrong' edge of a cam (cycle) signal is read, it may place the cam signal in the wrong cycle or set Tooth #1 on the wrong tooth confusing Speedy. ;) So IMO, if in-doubt or if calculating the correct operation is questionable, test in different modes to confirm best or correct signals and running with your particular setup and components.


PS: Often a timing light and cranking (with fuel pump off ) will verify the timing is both even and correct cylinders, or allow resetting Trigger Angle in order to test for that.
Hello all,

I am in the middle of the mechanical transition from stock 1.6 to 1.8 VVT Turbo in my NB. Or outside my NB to be exact, the engine is on the stand. In the meantime I'm trying to get my head around Speeduino. I found this tread and read most, and decided to help in order to be helped ;) The connector used in the opening post does not fit my loom, I have the later TE Connectivity 1123038-2 connector. And since I don't like all loose wiring, I've decided to make a PCB. Here's what I am up to:

Here's where I want the connector to go, physically:

I have started design on the PCB:

And I made an Excel with all Speediuno and engine loom pins:

Maybe I am re-inventing the wheel to a certain extend, but I feel I need to do this to get my head around what is happening everywhere. First thing I found is that a lot of pins of the engine loom will not be used. I don't mind, but especially a pin like "3S Immobilizer" seems to need something... Also I would like to add a boost control valve somewhere and I need to hook up pin "4R VVT Oil control valve negative" somwhere. And as you may have guessed by now, I have more enthousiasm than knowlegde.... I would like to host the excel somewhere but so far I haven't figured out how to do this.

Any advice / help is very welcome. If I succeed in making the PCB, of course the files will be available to the community.


Well, better late then never, I've redone most of my work mentioned above, this time digging deeper and working with EasyEDA so I can have a PCB made.

I've drawn a schematic, which will include the alternator control soon:

And started a PCB lay-out:
Which will fit the MX5 NB VVT plug and the Speeduino V0.4.4 as shown in the pic a little heigher on this page.

I made an Excel sheet trying to match all pins:
https://www.dropbox.com/s/ls0dhs3rh4nh5 ... .xlsx?dl=0

It comes with colours that actually mean something:
Green is what I am over 50% sure of, feel free to check.
Red is 12V / running voltage.
Yellow is what I think I don’t need to hook up.
Light blue is for the alternator field control, outside of Speeduino.
Unmarked is what I need to figure out, and ask your help for.

And I have many questions:
- Crankshaft and camshaft sensors from the engine: I’ve now hooked these up to VR1+ and VR2+ respectively, and connected VR1- and VR2- to ground permanently. Is that correct?
- The radiator fan. 2B on the MX5 connector is the fan pin, but do I want to control that from the Speeduino? We have CLT sensor, but wouldn’t it be simpler to throw a sensor in the radiator at the exit, hook up a relay and the fan to a switched 12V source, not use Speeduino for this?
- The heating of the O2 sensor, I’d like to ground that when the engine is switched on, but disconnect when the engine is at running temp. Is this logical? I think so, because the sensor will retain it’s own temperature by then due to the exhaust gasses. Can I use HC-1-OUT to do this, and if so, how? Or should I just ground it and leave it?
- There is a knock sensor signal coming from the MX5, 4M. Can we use that?
- I just connected all 12V / running voltages to each other, except for the battery plus which I don’t use. Right?
- The VVT control. The positive side of the valve is connected to the 12V, Speeduino should PWM the ground. Can I use HC-2-OUT for that?
- I will use the MAF sensor wire for boost control, as it is in the right location (yes, I’m going to turbo the lot). The boost solenoid (Pierburg 7.28197.16.0) has a two wires. Now there is pin 35 on the Speeduino called ‘boost’. But I read in the boost control page this is for a 3 or 4 wire boost control solenoid. Should I buy another solenoid, or can I use the one I have?

So, lot of work done, but I need to have a better understanding of what I am doing before I can finalise this.
All input is appreciated, cheers,

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