Injector signals.

[KiwiBacon]

I want to build a meter to tell me what the duty cycle of fuel injectors are. But I don't know what signal they take.

I assume PWM square pulse, what's the maximum voltage?

[UncleBob]

depends whether they are low impedance or high. High is a on = open. Low is PWM. Voltage for both is system voltage

Megasquirt FAQ has a lot of the details on the two different systems, with graphs and whatnot. www.msefi.com

If you're talking diesel, don't know much on how they work electrically

[KiwiBacon]

Originally Posted by UncleBob

depends whether they are low impedance or high. High is a on = open. Low is PWM. Voltage for both is system voltage

Megasquirt FAQ has a lot of the details on the two different systems, with graphs and whatnot. www.msefi.com

If you're talking diesel, don't know much on how they work electrically

Thanks, they are petrol injectors, my diesel injectors don't know what electricity is.

So a simple voltage gauge reading up to 14v (with a filter if it needs it) will tell me what duty cycle the injectors are running at?

The goal is a basic fuel economy gauge. There are some guys on www.gassavers.org who're talking about tapping into the VSS and making a MPG gauge, but with a little mental maths I figure one gauge will tell enough.