[ric355]

The OEM system on my car actually works the same way as the OP describes - it's a Lucas 14CUX. I sorted it with hardware using a separate relay that switches in power to the main relay when the ignition is turned on. If I were doing it again I would just junk the OEM stuff and rewire everything to get rid of it, but at the time I wanted to keep the OEM connector and loom in case I needed to swap back. I'm guessing it's a similar scenario for the OP.

[bluegizmo83]

Assuming you have ignition key fed supply to speeduino, then the condition "RPM >= 0" will always be true.

Unfortunately that wouldn't work too well, as the main relay needs to get powered on before the fuel pump relay gets power, plus if the engine ever were to stall while driving or at a stop light you'd instantly lose all power to everything that's powered by the main relay.

You've contradicted yourself in the post above this one ref battery voltage condition.

I said "assuming you have ignition fed supply to speeduino" --> translation: your speeduino is fed by 12v from the ignition key. In this scenario, if the key is on then the speeduino is on. If the speeduino is on, RPM is always >= 0 (greater than or equal to zero). So it'll work just the same as "voltage > 8". Both need Speedy to be running.

Your right, that's my bad, I completely missed that you said >= (greater than or equal to), I thought it just said greater than zero and dismissed it, my bad. Thanks for the suggestion.

[bluegizmo83]

The OEM system on my car actually works the same way as the OP describes - it's a Lucas 14CUX. I sorted it with hardware using a separate relay that switches in power to the main relay when the ignition is turned on. If I were doing it again I would just junk the OEM stuff and rewire everything to get rid of it, but at the time I wanted to keep the OEM connector and loom in case I needed to swap back. I'm guessing it's a similar scenario for the OP.

Yeah I had that thought about using another switched relay as you described as well. I think with the help of the comments here though I can make it work with a programmable output. I'm doing exactly as you did, trying to keep the OEM connector and harness so I don't have to rewire anything and can swap right back to the OEM ECU if I ever need to. My vehicle is a 2001 Kia Spectra USA model.

[ric355]

I'm doing exactly as you did, trying to keep the OEM connector and harness so I don't have to rewire anything and can swap right back to the OEM ECU if I ever need to. My vehicle is a 2001 Kia Spectra USA model.

Here's the rub: In my case, I had to add just enough extra stuff to make it unlikely I would go back to OEM (I needed extra sensors and a different injection loom), the old OEM loom (2000 year car here) is a bit crunchy and really should have been replaced anyway, and it all worked great so I never needed to revert and I probably never will. So I would think carefully about doing work to preserve the OEM stuff as it gets in the way of a neat installation and can potentially affect reliability.

[bluegizmo83]

I'm doing exactly as you did, trying to keep the OEM connector and harness so I don't have to rewire anything and can swap right back to the OEM ECU if I ever need to. My vehicle is a 2001 Kia Spectra USA model.

Here's the rub: In my case, I had to add just enough extra stuff to make it unlikely I would go back to OEM (I needed extra sensors and a different injection loom), the old OEM loom (2000 year car here) is a bit crunchy and really should have been replaced anyway, and it all worked great so I never needed to revert and I probably never will. So I would think carefully about doing work to preserve the OEM stuff as it gets in the way of a neat installation and can potentially affect reliability.

Thanks, I'll keep that in mind. However, I've already mapped out all the OEM harness wires for everything using a multimeter continuity test, and with my vehicle I'm not having to change or replace any of the OEM sensors/injectors/coils/etc, the only thing non OEM will be an added IAT sensor as the vehicle didn't have one and replace an OEM narrowband O2 sensor with a Spartan2 wideband (I'll still be using the OEM narrowband wiring harness since its already a 4 wire plug and that's all I really need for the Spartan2), so that O2 sensor would really be the only thing that would need to be changed for a swap back to stock, and to cap off the MAP vacuum port since OEM doesn't use a MAP reading. I highly doubt I'll ever need to go back to the OEM ECU anyway though, but I do like the clean install of using the factory harness and wiring.