Does anyone use the partial throttle corrections on either one of these? I am curious if the ecu will just over ride any corrections you make since for the most part they would be under 3k rpm. The reason I want to do this is when I tuned my car I had to turn my fuel pressure up in order to have enough fuel up top. So now while I am cruising down the highway the wideband reads a/f of around 12, it used to be 14 something, and my fuel mileage is not too great. Just wondering if anyone has experience make partial throttle corrections on either the VAFCII or SAFCII. Thanks.

 

Have you bothered to check your KS, O2's, TPS, or codes?

 

my cel is always on. What I am saying is that everything was fine until I raised my fuel pressure. I want to know if anyone has used partial thottle corrections.

 

Unplug the O2's, streetz had a thread on it.

You'll run somewhere in the 9's-11's but once you get the idle correction set, it's fairly linear upto 3K/3V.

 

I'll look for streetz thread.

So you are saying that I would be able to make corrections after the 02 sensors are unplugged, but while they are plugged in they will override any corrections I make? Just trying to make sure I know what you are saying.

 

I use them when tuning my car, it helps with part throttle accel. I even had a setting it 1k to adjust idle.

 

Did you still have your factory O2 sensors plugged in when making corrections?

 

Once you unplug the O2 sensors, the ECU goes into open loop, and uses a default map to determine the injector pulse. It sounds like when you increased your fuel pressure, you overwhelmed the ECU's ability to regulate AFR at 14.7 through the short and long term fuel trims.

I think if you make partial throttle corrections with the O2 sensors connected, it would work in conjunction with the short and long term fuel trims. Manually leaning the mixture would allow the ECU to get back into the range where it could regulate AFR effectively. You may be able to look at the fuel trims with an OBDII reader, to see if they are at the extremes of their range.

Or if you disconnect the sensors, then you wouldn't have to worry about the ECU changing the fuel going to the engine, because it would be operating on the static, default map.

The more elegant solution would be to continue using the O2 sensors, and make the corrections to allow the ECU to regulate AFR at 14.7 closed loop. The easier solution is probably unplugging them.

EDIT: A little detail from that Streetz thread posted by nismology

 

Unplugged em and noticed a HUGE loss of performance, even with the partial throttle tuned to 12.8 AFR then... so I guess it does pull timing quite a bit

 

It would be nice to confirm that with a timing light or EU log.

 

yes, had to cause I can't pass emissions without it or a cel

 

the ecu will try to adjust with enough time but it doesn't happen fast enough to matter cause who drives at any given rpm and throttle % for more than a few seconds

I know at idle it would take about 1-2mins when warm before the ecu would try to adjust but it did matter cause I don't idle much longer than the time it takes for a traffic light to change. And if I get suck in traffic I just blip the throttle from time to time