http://eecanalyzer.net/tech/docs/GUFB.pdf This is the GUFB code disassembled that i borowed from eectuning.org If you read and understand this, you will know what works and why. I see a lot of people doing things that do things that throw the eec for a loop and then they have idle/drivability problems.. I'd like to start with a basic of how the eec works and what it is looking for and what causes common problems.. I'll start out with the intake path and the problem of having vaccuum leaks.. In a factory setup, the mass air will measure all the air coming in to the engine assuming no vaccuum leaks. When a vaccuum leak is introduced, the eec no longer knows how much air is entering the engine. A mass air eec uses the volume of air entering the engine to calculate the fuel and spark curves. Hence if it has unmeasured air, it can not properly calculate the curves. This is why valve cover breathers are such a bad idea. Look at the diameter of the PCV hose and that's the vaccuum leak diameter you are introducing into the system. By running a breather, the pcv system will pull fresh unmetered air through the breather. If you'd like a better example of the vaccuum leak, take off the pcv hose and put your thumb over it. That is how much unmetered air is going in with a breather. This is why it is also essential that all vaccuum hoses and solenoids are in good shape. Anything not used MUST be blocked off. Anyone with any corrections or questions, post in this thread. I'd like to get a comprehensive thread of how the eec works and how common mods effect it.
Jeez, at first I understood reading it then I just got lost in mainly definitions and initials...Good stuff though.. That doesn't pertain to A9L though does it? Besides the basic open loop/closed loop calculations
If you really want to understand the computer for the A9x or GUBx read this book.. Amazon.com: Ford Racing M1832Z1 Electronic Fuel Injection Book: Automotive It's give great information about the computer systems in our cars. Plus, that .PDF can be rather boring.
