I was reading in one of my books today called "how to modify and tune fuel injection" at work with all my free time. I have read up on some useful facts for all you guys using Adjustable Fuel Pressure Regulators.

TThe book states that "while at the track or if your about to race that you should unplug your O2(oxygen) sensor. When the ECM enters the closed-loop mode the oxygen sensor will report enrichment of the fuel to the ECM. The injector pulse width would then be shortened, leaning the air/fuel mixture, and defeating the benifits of the fuel pressure regulator. Disconnecting the O2 sensor would either keep the ECM from entering closed-loop or deliver a nuetral air/fuel ratio signal to the ECM if it does.\

Just a little helpful advice. Tell me what you think.

 

I didn't think that the ECM uses the O2 sensor in closed loop mode.

The only way that I could see that this would make a difference is that the computer locks the BLMs at 128, but that you actually have more/less fuel adjusted with the AFPR.


I'm not sure, but wouldn't that mean that your AFPR wouldn't be setup properly for no/unplugged O2? Or vice-versa if you setup up with it unplugged?

 

That's what closed loop is. The O2 sensor is feedback that closes the "loop".

If you really want a lesson on all this kinda stuff, read this stickies in the PROM forum.

 

I have the exact same book, but I don't remember that. What page was it on? That book never says which system it is talking about though. There are a great deal many systems out there and all will act differently. If you unpug it an ECM might resort to "Limp home Mode" After spending all of the time to read and understand that book I learned that you should tune a car properly and not take anyshort cuts that could result in costly engine damage. Too much fuel will wash oil off cylinder walls, and rev very slowly at best.