Low voltage and PE values
Low voltage and PE values I rough tuned a friends car the other day on the street. Cruising around got his heads/cam/stalled auto to idle perfect, also made drivability much easier on him. While loggong I noticed his voltage (through pcm) was only 12.4vdc cruising. So long story short the only way I could pull his afr into the 13.0 range was to use a pe multiplier of 1.25 from 4800 up. I've never had to have a multipler that high on a heads/cam setup and I'm warning him not to drive it until I can figure out if maybe his IFR isn't right or some other factor is at hand (this is another tuners base tune btw).
Has anyone seem something simular to this? I may try and swap alts to see if I can pull the supply voltage up.
Has anyone seem something simular to this? I may try and swap alts to see if I can pull the supply voltage up.
sounds like your fuel pump is not getting enough voltage, thus supplied fuel pressure is way lower than what the computer expecting/calibrated for. For the time being I'd calculate IFR to match the flow rates based on fuel pressures at different manifold vacuum ranges. The real problem is in the hardware though, so fix that and the IFR and PE is going to make a lot more sense.
