I've done my searching, I am unable to get a usable Duty Cycle for my injectors. If you can share your calc that would be great.

1. What obdII paramater equates to Pulse Width? I have: Fuel System Status 1/2, Short Term Fuel Trims 1/2, Long Term Fuel Trims 1/2, but no pulse width. Do I need to calculate this with another calculator?

2. While setting up rescale calculator, is there some trick for inserting unit as %? I only see text/numeric values, how can I select special characters?

Here is the basic Injector Duty calculation posted by DrewTech:
Input Signal: IPW Paramater
Multiplier Signal: RPM(I'm using ZT-2 RPM)
Multiplier Sign: 1
Constant Multiplier: .00083
Offset Signal: Constant Offset
Offfset Sign: 1
Constant Offset: 0
Name: IDC Bank 1
Precision: 1
Units: % (Not an option!)

 

call needswings.

 

You'll need something that can read IDC and neither the DashDAQ or the ZT-2 can. If you're looking to add that and some more inputs, the Innovate SSI-4 will give you what you need. Input 3 is selectable so you can read duty cycle and you'll need to grab an injector wire.

 

Can you put a dwell meter on an injector wire? Like we did on old points type ignitions.

 

Damn good question!

 

This would be a very round-about way of getting it but yes you could use a dwell meter. Dwell is measured 0-90 degrees so you'll need to multiply it by 1.1 as IDC is amount of time on for the total amount of time on and off (0-100%). This may or may not read the same for marine or small engine meters, but if it's for a 4-stroke it will read this way.

 

Rudy, what wires need to be connected to the SSI-4 Ch+ and CH- in order to measure IDC? Would you tap pin 27 on the C3 connector or tap one of the injector wires? I want to read the IDC% and correlate it with the other data that I'm logging.

 

Looks like I got it to work. Able to get to 70% IDC just driving hard around the block.