another Alfa Romeo conversion

[festy]

This is TIG welded, but the scrap I used for the end plates seems to be some form of alloy (5xxx?) that doesn't weld well to 6000 series - if it still leaks after this, I might cut them off and use some 6061 plate for the caps.

[festy]

No more fuel rail leaks!
When I get a spare hour or 3 next, I'll re-fit the exhaust and feed the tacho signal into the ECU, and see if it will start with the ECU controlling fuel only.

[festy]

This is a reluctor distributor, right?
And a reluctor pickup produces a short AC pulse, which I'd need to convert to a TTL square wave signal to use as a distributor reference for the 808?
This TTL pulse is normally generated by the Camira ignition module isn't it?
What sort of pulse width does the 808 expect? Is 1ms in the right ballpark?

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[Holden202T]

yeah it looks like it is.

[VL400]

Here are some scope caps from testing a camira module. The pulse width depends on the trigger wheel, but pretty much any 5v square wave is fine .... https://pcmhacking.net/forums/viewtopi ... =40#p12856

[antus]

Do you want to avoid using a camira module, or just sussing out the best plan of attack? If you do use that module, then it'll convert the sine wave pulses to square wave for you and provide tolerance to over 20v at higher rpms when the volts rise.

[festy]

I don't have a camira module as I'll be going DIS, and was just looking for a simple way to feed reference pulses into the ECU for an initial test with the ECU controlling fuel, but spark still handled by the stock ignition system (I don't like changing lots of things at once, makes fault finding harder).
If i had a reluctor amplifier handy it'd be simple, but after thinking about a circuit to cater for the voltage increase with speed I'll take the easy way out and use the coil ground as a reference, it's a lot simpler to get a 0-5v pulse out of using garden variety components

[festy]

Here are some scope caps from testing a camira module. The pulse width depends on the trigger wheel, but pretty much any 5v square wave is fine .... https://pcmhacking.net/forums/viewtopi ... =40#p12856

Is the ref + input on the 808 (pin B5) a 5v or 25v input? I'm guessing by the scope caps it's 5v?
Hypothetically, if someone was stupid enough to put a 12v signal on that pin, would that person then likely be in need of a new ECU?
I think I might need to hook up a 5v square wave oscillator to the ign ref pins to see whether I've done any damage or not

[VL400]

Well the ignition module output is 5v but it can prob survive 12v. You do also need to use the ref - pin.

[festy]

I wired up a pic producing a 10hz square wave to the ign ref input and before I could glance at the laptop I knew it must be working because the injectors started clicking away - so I didn't manage to toast the ecu the other day
I then tried an optoisolated spark sensor circuit I based off the megasquirt schematic, and it gets a signal.... of sorts.
TP shows rpm off the scale, i.e. over 10000rpm with the engine slowly cranking over.
I'm starting to think I'll just go ahead with the dfi setup instead of wasting time with getting this test working.

Edit - a decoupling cap on the coil neg input made all the difference, I now have a half reasonable rpm being logged during cranking.
Definitely closer than the 23000rpm I was seeing without the capacitor

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