Progress Thread finally tuning (and more)

[AeroCoupe]

Then that is where you set the pressure at. My sheet was at 43.5 but the tuner bumped it up to 46 as it needed a little more fuel up top. It’s fat now due to me getting the injectors cleaned and they gained about 4 lb/hr on average and the spray pattern went from absolutely terrible to what a person would expect.

 

[JD1964]

Shouldn’t the EEC be able to adjust the pulse width for variables? I mean, if it’s tuned properly to begin with including leaving a bit of room on each end of the fuel table, the computer should be able to handle adjusting to some worthy degree. Does that make sense?

 

[AeroCoupe]

The stock EEC-IV can compensate +/- 10% but that is across the board so cumulatively. If it only needs to trim fuel then typically it can compensate.

What I do not know but assume is once you tune it with an external chip I believe you loose that compensation.

Maybe @Mustang5L5 can jump in here and lay some knowledge on us.

 

[Mustang5L5]

The stock EEC will try to compensate by shortening the pulse width, but without correct injector settings it can get messy fast. I’d have to dig into the GUFB doc I have for the stock ECU on Mon. I’m actually curious so I’ll take a look but it’s 600+ pages so get hard to decipher. I don’t want to say anything way off from the truth

In terms of aftermarket tuning, if you want to run a higher pressure you typically have to use offset compensation for the injector settings.

For example with my 47#er. I set mine as close to 39.15 to avoid having to do offset calcs

 

[JD1964]

I’ve got a wire connected to my PLX wideband which I will use to data log through pin 27 in the EEC and into BE. Pin 27 is the EGR circuit as some of you already know. I won’t be deleting the EGR system but rather retaining it in the end. Instead I’ll be borrowing the EGR circuit. The data logging wire runs through the firewall and over to close proximity to harness connection for the EGR. I’ll data log for the tuning process then switch back to functional EGR afterwards. I’ll simply turn off EGR in the tune, unplug the harness and tap the pin 27 wire at the EGR harness in the engine compartment. I made a single push pin type connection pigtail specifically for the purpose of temporarily connecting to the harness for data logging. It’s super simple to revert back to functional EGR after tuning. Absolutely zero permanent modification of the factory wiring.