2 replies to this topic

[97V850T5]

After over a year of tuning my car is still a bit of a mystery. It has ran rich from the start. All the Stage 0 stuff is complete. I use an HKS SAFC to control the fuel curve. So, with my modifications I thought that increasing the amount of fuel would allow me to run more boost. But it is just the oposite. When I turn the fuel curve down 20% I can run up to 17psi. 5 and 10 psi come on faster and more stable than stock. Why is this? I thought it would have been the 02 sensors. First I tried tuning it with my Apexi Turbo Timer that displays A/F ratios my the voltage signmal from the front O2 sensor. The stack O2 sensor displayed around .34 and up to 5.00 at WOT. Now, with a new O2 sensor it is displaying around .15 and still 5.00 at WOT. THis is strange to me. At first I had a Dawes Device a/f gauge with four lights and it always showed me running rich. But I thought rich was like .90 not 5.00 volts. I though an O2 sensor was to run at milivolts .1-.99. Why are both O2 senors ive installed saying 5.00 at WOT. Now, I now people who use wide band sensors say that you cant tune with the stock ones, but if the stock ecu uses their signals they must do something. Does anyone know whats going on. Did my removal of the crank case hoses screw with the a/f ratio that bad. I just let both vent to the atmosphere. And why I can run so much more boost just by turning down the amount of fuel. It makes no sense with my other mods. Please help

1997 Volvo 850 T5
HKS SAFC
Apexi Turbo Timer
Injen Intake
Pipercross Filter
Custom 2.5 Exhaust
Brembo Brakes
OMP Strut Brace
RalliArt Seats
Ceramic Coated Wheels
Akimoto Hoses
Custom Cooled Intake and intercooler
etcetcetc

[lax01]

well if you removed the crank case ventalation hose completely, you are just venting metered air to the atmosphere and thus would run rich....have you tried replacing the PCV?