Lets Talk About Injector Offets

[yawpower]

Hi Guys,

I was searching for Ford injector offset and ended up here. This is exactly what I was looking for.

We have a test bench designed specifically for quantifying injector offset (Also referred to as dead time)

Years ago I helped a guy with a Superchips something or other and I remember seeing the offset, and slope values. My reason for the search was to find out exactly what data the ford ECU's require so that we could include it in our service.

The short story is that I can gather the information you guys are looking for, but I need some help determining appropriate units.

I assume that the slopes refer to the actual slope of the flow vs pulsewidth curve in the upper and lower non linear operating range of the injector, but I may be mistaken.

In any case, we can gather the values for any injector, we just need to know exactly how Ford defines the slope.

If anyone would like to offer this detailed information, I would gladly offer a Ford ECU specific test for injectors.

I could type for hours describing the process/service but it is probably easiest to guide you to the appropriate section of our website.

The Injector Dynamics section is here:

http://www.yawpower.com/injectordynamics.html

Thank you.

Paul Yaw
Yaw Power Products

 

[yawpower]

Hi Guys,

I should have read the previous information more thoroughly before posting. After a closer look, I think I have a handle on it. If not hopefully someone can correct me.

High Slope defines the slope of the flow vs pulsewidth curve in the linear operating range of the injector.

Low slope defines the slope of the flow vs pulsewidth curve in the lower non linear range of the injector.

The breakpoint defines the point at which the injector goes non linear.

If this is correct, it leads to several questions. First, what are the X and Y units used to define the slopes. The X axis is probably milliseconds, and so that leaves only the units of the Y axis in question. If the static flow rate of the injector was known, it shouldn't be hard to determine the units.

The remaining question which really has me scratching my head is the breakpoint.
The breakpoint as I defined it above varies with battery voltage.
Hmm....

Also, where could I download the software that you guys are using?

Thanks again.

Paul Yaw
Yaw Power Products

 

[Stanger007]

Post this up on eectuning.org and you will get some excellent answers - be sure to ask the guy by the name of "sailorbob", he has the best knowledge of the disassembled EEC code.

The breakpoint will be the point at which the low and high slopes both calculate the same pulsewidth. It is not a hard switch between the two slopes, but rather a curve fit.

The "Injector Offset vs Battery Voltage" is designed as an adder to the calculated pulsewidth to counter any voltage driven inaccuracies.

Wes

 

[m0l0]

Hi Guys,

The remaining question which really has me scratching my head is the breakpoint.
The breakpoint as I defined it above varies with battery voltage.
Hmm....

Excellent information you have provided, and to kinda answer you question , at least in the most common ford EEC ´s the breakpoint is a static value provided from the inyector information , and fine tuning , to compensate any volt. difference there is the injector offset vs. battery volts. This graph does not move the breakpoint it just a pulsewith adder.