I just did the 1+ ecu upgrade with 225TT fuel injectors, 93 octane program from ECS tuning. I installed the injectors, no prob. I took the ECU to them, brought it home and put it back in the car. ('02 1.8 quattro, 85k) A day later the CEL came on and I don't see any increase in power, plus my MPG went from about 24 mpg to 34 mpg!? Ran the diagnostic - system too rich. Does this mean the upgrade didn't work? I'm calling ECS tomorrow - I'm assuming they'll take care of this problem?

 

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they flashed you with just the stage 1 file and you are dumping too much fuel with the TT 225 injectors. They will have to re-flash the ECU. I recommend putting your stock injectors back in until you get the re-flash.

 

not the highlight of my B6 experience

As below, you must pull the error codes to diagnose. Take to your local APR dealer

 

due to the lower injector duty cycle necessary with the larger flow rate injectors, during cruise/low engine load conditions. (boost pressure &lt; or = to stock max boost pressure)

 

The injector duty cycle calculation only goes out of whack when the flow rate of the injectors is changed from the factory default.

 

not an injector size dependent situation. The injectors are driven by whatever duty cycle the software calls for, the ECU has no way of knowing what the actual flow capacity of the installed injectors is compared to the expected flow rate as specified in the software. Regardless, the DIS MPG calculations use the stock injector fuel mass flow rate values that are not calibrated accurately when running a chipped ECU. Chipped ECU tuning uses different injector duty cycle to increase fuel mass flow/time as required for increased hp output, in the case of stage one with stock injectors, the DC increased, in the case of stage one plus, the injector flow capacity is higher and the injector DC is modified (reduced DC% except at higher than stock mass air flow rates,) as well. In either case, the DIS MPG calculations assume stock injector mass flow rate, with stock injector DC%. Especially when running 386 cc/min TT225 injectors, the low load DC%/pulse width is a lot lower because of the similar mass air flow at light load cruise compared to stock, so the DIS interprets the shorter pulse width as lower mass fuel flow /mile, but the actual mass fuel flow rate as programed in the ECU chipped software, is about the same as with stock injectors that would need a higher injector duty cycle percentage for the same cruise conditions.
EDIT: There is an adaptation channel in the IC that can partially offset the calibration error, and improve the DIS MPG accuracy.

 

There's two variables that determine how much fuel goes into the intake; injector flow rate, and duty cycle. The DIS cannot measure flow rate, so it must measure duty cycle. If the flow rate does not change, the DIS calculations will be accurate regardless of the ECU software, since the only way to flow more fuel into the intake with software is to increase the duty cycle of the injectors.

This has also been my experience; the DIS keeps proper mileage with stock flow rate injectors, and keeps inaccurate but consistent mileage with higher-flow injectors. The only variable I can think of that skews the linearity of this calculation back to the stock calc is the apparent hard-coded maximum of 40L/100km (or equivalent) that the DIS records, even when &gt;40L/100km of fuel is flowing into the intake. Not sure if that's a DIS display issue or if the actual calculation has that maximum in place.

The adjustment channel is nice, but doesn't provide enough headroom to compensate for the 380cc/386cc injector flow rate

 

And does not determine fuel flow rate itself. I may be wrong about the stock injector/chipped DIS MPG accuracy, but we agree on the 386 cc/min injectors and the associated displayed MPG error.
I concure about the limited range of the adaptation channel though, it could have been wider.

 

dtc: P01172 Bank 1, system too rich