Fuel

[FORSFED]

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?

[niterydr]

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.

[LightningGSX]

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.

[john]

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.

[Shane@DBPerformance]

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%. :)

[PSI2HI]

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

[Kracka]

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.

[Jacek]

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

[FORSFED]

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...

[LightningGSX]

Originally posted by TalonTSiDude@Feb 12 2004, 12:33 PM
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.
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.