Thread: VF570 installed
View Single Post
      12-16-2012, 07:36 AM   #95
pokeybritches
Colonel
pokeybritches's Avatar
United_States
479
Rep
2,782
Posts

Drives: ESS/G-Power Z4M, VF Z4, 996tt
Join Date: Sep 2009
Location: Los Angeles

iTrader: (12)

Garage List
2006 BMW Z4M  [10.00]
2006 BMW Z4M  [8.50]
2003 BMW Z4 3.0i  [9.00]
Quote:
Originally Posted by Rated M Roadster View Post
I believe that would just tell us that the injectors are maxed out; thus needing bigger ones to stay between 80 and 90 percent duty cycle. The problem looks more like something is telling the ECU it needs less fuel, so it's cutting the injection times. As stated, they should continue to increase instead of decrease.
The reason I think the duty cycle would go beyond 100% with an inadequate fuel pump is because the ECU would continue to try to adapt and add more fuel (just like with injectors that are too small)...

1. ECU adds what it thinks is the correct amount of fuel, based on the map.
2. O2 sensor reports a lean condition.
3. ECU increases duty cycle to add more fuel.
4. O2 sensor continues to report a lean condition.
5. ECU continues to increase duty cycle to add still more fuel... eventually going over 100%.

I think you're right about something telling the ECU it needs less fuel, rather than the car not being able to supply enough. Hopefully VF will clear it up. They recommended I get a Bavarian Technic tool when I had some minor issues with my car (ended up being install error), so maybe it will be my next purchase.
__________________


VF Engineering Z4 3.0i, ESS Z4M, G-Power Z4M, 996 Turbo
Appreciate 0