I was looking to make somthing that i could hook up to my injector signal on the ECU. I want to monitor my injector duty cycle... I was wondering if anyone made some kind of digital display or know someone who has the schematics for this??

 

It's called a Fluke 88.

 

ya but fluke stuff = $$$$$

actully I wouldn't mind having something to veiw mine either.

 

i bet aaron cake might be able to give you a good answer. his site www.aaroncake.net has a forum that includes a section on electronics where you can ask questions.

 

all you need is a ADC (analog to digital converter), theres a really simple one for PC's available from http://www.picotech.com that can connect to a parallel or serial port. So you could datalog and plot in realtime any analog signal, including your injectors.

 

there is one here:

www.ggimages.com/rx7/pwm.html

It needs to be calibrated with a scope and a signal generator, though.

Hugues -

 

Couple that meter with a wideband

James

 

Easiest way would be to find someone who has an oscilloscope that you can borrow. Another option is to purchase a legacy oscilloscope. I have one on loan from someone to help with a project I was doing. (we're talking circa WWII) Apparently vintage oscilloscopes are quiet cheap and fairly easy to come by. It would be more than sufficient for your applications, but you're going to need a second person and it won't be as robust as your typical gauge.

That picotech thing is quiet cool. You could also hook up a run of the mill ADC and measure the output voltage with an oscilloscope. This solution would likely be a lot harder than that picotech, but cost a lot less.

The problem is with just building a conventional gauge is that the pulse width changes rapidly. Even with a oscilloscope you'd have to try to hold the conditions for a brief period or get a more modern one with hold capabilities. A system like that picotech would be the most informative.

 

i found this.... EFI Systems Air Fuel Ratio/Injector Duty Cycle Meter does anyone know anything about this unit? good, bad?

http://www.extrememotorsports.com/ggcat/efiafm-l.jpg

 

i found it on a eclipse web site

http://www.extrememotorsports.com/ggcat/afgauge.htm