Hello,
While I am waiting for all the parts to arrive. I have been working on the wiring diagram. I have taken the diagram from different sources and modified it to match what I want. Can people who know more about the wiring of a Megasquirt 2 v3.57, please check the diagram for me.
Thanks
Another question is about the Shielded Twisted Pair wire. What is the view on adding a weather pack connector between the Megasquirt and EDIS connectors? Can I do it or will that open me up to noise?
Very pretty, and a lot of work. I did notice a few things to comment on. For each injector bank, you have two injectors on one DB37 pin, and a single on the other. Are these hi-z or lo-z? If lo-z I might suggest doing a 3-1-2 or 3-2 wiring splice, just to make sure nothing gets over heated.
Your SLC EVK boards have the heater grounds hooked up, but not the logic grounds. I realise it's far less critical when using I2C vs linear / analogue, but IIRC Alan still recommends separate grounds - heavy to the block or battery, logic to the MS sensor ground pin.
On the topic of I2C, how long are the SCL/SDA wires? You may need an I2C booster.
Have you talked to Jean about powering the TIOx off the Vref pin? I realise this is a boxed MS and not a uS, but there are still limits to what the pin can supply.
Temporarily shut down - back soon!
QuadraMAP Sensor Module -- PWM-to-Stepper Controller -- Dual Coil Driver
Coming soon: OctoMAP Sensor Module TTR Ignition Systems
Hello,
dontz125 thanks for looking at the diagram a second time. I hope to have more time later this week to work on it again.
Yes the injectors are low-z... The wire is 20ga so can take up to 10A. The 5A fuse should be enough from the information I have found. So it should be OK, but will take the advice and look at doing a 3-2 splice. Should both wires go right to the plug?
Just was doing another bit of reading about the injectors and fuses. Should each injector have its own fuse or can I connect 2 together. I think when I connect 2 the fuse should be 7.5A and not 5A.
OK I wasn't sure about the logical ground on the SLC EvK board. I was in the process of asking that question on the 14point7 Forum.
The I2C wire should be short. I plan on having the 3 boards in one case or at least next to each other.
From talking with Jean he said that is was OK to power the TinyIOx from the Vref of the MegaSquirt.
But I know that if I don't want not to use the carrier board for the SLCs I would need a separate 5v circuit to power them.
Maybe once I have the boards in my hands I can see a bit clearer.
I can see a 5V on the bottom left of the board would that be the place to connect it? what about the ground?
Also want to see the colours of the O2 senors wires and how they match the board. as what is written on the board in the documentation doesn't match the colours of the wire to the connector.
As Don says, powering the TIOx from the EVK board is a better solution even though the drain on the Vref pin would be very low. There is a 5V available on the JP5 header on the EVK board and the pin next to it is the ground. Have a look at the SLC documentation for the schematic and picture of the board.
luxmoggy wrote:If I power the TinyIOx from one of the SCL EvK. Do I also need to do that for the Fuel Pressure sensor?
Any sensor that you connect to the TIOx will need to be powered from the same source. Otherwise you would have a potential offset. You also want to return the sensor ground to the TIOx ground.
I asked this on your other forum, but it could be interesting for other people.
How easy is it to piggy back off other sensors in the car. Eg the speedo, oil pressure
So that the signal still goes to the dial/gaiage and also to the TinyIOx.
What type of sensors? Are these powered by 12V? Do they connect only to a dash gauge or are they connected to an ECU or another device? Sharing a sensor that generates a 0-5V signal such as MAP sensor is usually not an issues and you should be able to just connect it to both but any passive sensor such as a thermistor is another thing and is not recommended.
You might be able to use the speedo signal but the single wire sensor will not work. You might be able to get a reading but that will be meaningless. Without a return ground you will have noise and offset. It is also not powered through a regulated 5V source.
Unfortunately, it is almost never a good thing to try to share sensors between a gauge and an ADC input. A timer input such as the speedo is likely more doable.
My car has 2 sensors for the oil pressure one for a warning light and one the gauge.
If I replace the one that is the warning light with a proper sensor. Can I get MegaSquirt to trigger the warning light.
Hello,
Hopefully on the last changes on the wiring diagram. Once the parts all arrive I will check the wire colours match the diagram. Also plan which wires need to go through the bulk head.
would this work as an output circuit for the warning lamp?
Do I need to have an ADC Conditioners circuit for the 2 pressure senors inputs?
That warning lamp circuit could be fairly robust,depending on the components, but that's not necessarily a bad thing. Yes, you need a filter, but not that one. Look in the manual under schematics, and you'll probably want something like the MAP sensor.
Temporarily shut down - back soon!
QuadraMAP Sensor Module -- PWM-to-Stepper Controller -- Dual Coil Driver
Coming soon: OctoMAP Sensor Module TTR Ignition Systems
Out of interest why the difference in the conditioning circuits for MAP and TPS?
E.g why is the other conditioning circuit better for the pressure sensors.
Some values are based on what the OEMs do; others from datasheets or industry common practice. Unfortunately we've run smack into the limits of my competence, so I can't comment more intelligently than that.
Temporarily shut down - back soon!
QuadraMAP Sensor Module -- PWM-to-Stepper Controller -- Dual Coil Driver
Coming soon: OctoMAP Sensor Module TTR Ignition Systems
