Syvecs Forums

stevieturbo wrote: ↑Sat Apr 18, 2020 12:10 pm

TimH wrote: ↑Sat Apr 18, 2020 11:48 am
Not sure about protection - I would hope there is, as that would be good design practice.

I busted a fuel output on an S6...so no protection there.

The age of the S6 design may mean the injector driver devices are not self-protecting and a short to 12V might kill them. More modern omnifet injector drivers have inherent current limiting and thermal protection - but guess you can still kill them somehow!

That would make sense, TTL signal can be anything below 1v is off and anything above 3v is on, so there is a tolerance.

I'm about to do some work on my car anyway and I have the ignition wires accessible for testing, I'll throw some leds on and see how they fair up, maybe without resistors they will be fine if the voltage is low enough

Graeme

I would use a resistor. Let's say the Vf of your diode is 3V and the ignition drive is 3.5V - without a resistor the driver may fail as too much current is drawn. A 22ohm resistor would limit the current to 20mA and keep it all safe.

I don't have any resistors that low, I'll play around but use what I have and see what we get to start with

Graeme

Pretty pleased actually

I hooked up a white led with a 470ohm resistor and it worked fine and was much brighter than I expected considering the resistor size.

My ecu is in the boot so I used a long length of wire to simulate any voltage drop too

Excellent!

I would of thought 3 or 4 of these would be OK on one output with 470 resistors?

Graeme

If the TTL output is 3.5V and the Vf of the diode 3V, say, then you are only drawing 1mA - which is nice and low so must be a super-duper nice-n-bright LED

So, yes, 4 would be AOK

Thanks Tim

They were about 4 pound for 50 off ebay haha, it said ultra bright, I guess it didn't lie!

Graeme

Other option would be buy a full shift light lol