I was doing a little logging today and noticed that I was having almost 0 knock count across the board, good o2's around 0.9 - 0.92, but was maxing out my injector d/c at 100%. Mods on the car include 2g mas, 550's, supra s/m, ic piping, walbro 255, 14b running 15lbs, and an afpr with base fp set at 42psi. Even adding in the cold air the injectors shouldn't be open that much should they?? Opinions?

2g mas figures to be 18-22% leaner than factory
550's at 43psi baseline are 22% richer than factory.
at 15psi, its possible, 02 voltage shows a little rich, but without timing curves and a wideband its hard to tell.

His eprom chip has the 2g mas calibration values in it, as well as compensation for the 550's, so it shouldn't run any leaner/richer than with a factory 1g mas/injectors.To me it doesn't seem like actual %100 duty cycle would be likely or even possible with that setup, I'm more book educated than experience educated though.

Do you have a SAFC to tune with? If so, turn up the fuel pressure a bit and lessen teh injector signal on the SAFC. If you do not have a SAFC, I recommend one.

Anyone else ever have trouble believing the duty cycle numbers that people get out a lot of these loggers? I think everyone is running 95-110%. :)

I have grown very biased against the logger as i've noticed they have glitches in their programs as well. I compared 2 seperate loggers on my 93 TSI awd w/ very different result in 02 trim/voltage and knock counts.

No way your maxing out 550's w/ a 14b @ only 15 psi unless your have some junk injectors.

Nick

I know me and CVD both have gotten up into the 130's with 550 injectors on 16G's...no way that can be accurate.

i am going to be logging my car and i have rc 550s and 2g maf this weekend so ill tell you what kind of duty ill be pulling

I'm having a hard time totally believing in the d/c readout right now since I was at 80-100% on the stock injectors...

But I did forget to mention as lightning added that I have an eprom chip calibrated for 550's and a 2g mas. With that in mind, shouldn't the ecu be calibrating the appropriate amount of fuel accordingly? If that was the case isn't 100% way too high? I would think it should be more like 50-60% range, but that's just my guess. BTW, I do have an afc, but it's zeroed out at the moment. I'll see if I can get any different results upping the fp and lowering the afc a bit.

Jacek - let me know what you get for numbers....although you'll be different if you don't have the same ecu as I do...

130% duty cycle? Thats impossible, If you get percentages over 100 your logger is wrong, duty cycle can't exceed 100%.Did anyone notice the injector pulsewidth and RPM when you got these numbers? Its easy to calculate actual duty cycle with pulsewidth and RPM.And yeah actual 100% duty cycle is very bad, your ecu no longer has control of fuel.

I went out today and took a few logs this time rather than trying to watch the max readouts on the big number display. Interestingly enough it showed on the graphs that my d/c was reading about 75-85% at WOT up to 7k... I'm thinking this is more accurate, however I don't understand how looking at it in that mode would make such a huge difference. Maybe those loggers are flawed when they added the large number displays....

What were your pulse widths at that RPM?

Looking back at the logs it seemed pretty consistant that I had a p/w of 14.5ms at 6500rpm. That translates to nearly 80% by one of those conversion tables, which is also close to what it reads for the d/c when I change it to that option. I was just getting the 100% when looking at the large number display the other day and not actually logging....

im pulling the same duty that ecoli said at 40psi base fuel pressure. my first gear had a higher % around the 100s while 2nd and 3rd had lower around in the low 90s or some crap