Hey guys,
Just finished installing the Stage II kit today.
We adjusted the base PSI on the FMU, to the 35psi.
I turned the car on, and let it idle for the recommended 10-15 minutes. My idle AFR's kept ranging between 16:1 to 18:1
We didn't get a chance to take the car out for a drive to adjust the WOT psi to the 85-90 values, because I am worried about the Idle AFR's. I did blip the throttle a couple times, and noticed the wideband needle drop down somewhere between the 13.5:1 - 15:1 range.
I know that decel AFR's should be up around the 18:1 mark, but what about idle?
Any ideas on why it's idling so lean?
2004 Cavalier LS
Hahn stage II
maybe because your fuel pressure is so low
Once it's warmed up it should go closed loop and idle around 14.5-15.0:1. Do you have closed loop disabled?
Skwirl - In the instructions for the Begi II FMU, it says to adjust for base pressure. A stage 1 is @ 55psi, and the stage 2 is @ 35psi. I have the stage 2 system.
Oldskool - I don't have closed loop disabled. It's the stock ecu. I let the car idle until it was up to temperature, but the wideband still read lean.
The gauge came with the kit. We hooked it to the valve on the stock metal fuel line (that's beside the brake master cylinder) and adjusted the base (idle) to the 35psi. There are no leaks
The wideband is mounted at the proper angle, before the car, and the recommended distance away from the turbo. I don't have any DTC's. I'm wondering if on my wideband I happen to have a bad ground connection. Every connection for the gauge is soldered, shrink tubed, and then taped. I'll double check the ground location.
Any other ideas?
turn the fuel pressure up a tad bit
Boosted - Turn the fuel pressure up to what? 37? 40? I spoke with the Tech's at Hahn, and 35 is fine.
Anyway, I found the problem.
I double checked the gauges, and my AEM analog wideband was giving me an error code light. I pulled the pillar pod off and noticed that the connector was in halfway. I plugged it in properly, and then started up the car.
I took it out for a quick drive and tuned it as per Hahn's specs for 85-90psi @ w.o.t.
14:1 - 15:1 @ idle.
13:1 - 13.5:1 @ normal driving
11.5:1 - 12:1 @ w.o.t.
I didn't notice ANY leaning out to 14.7:1 AFR. My car always drops down to the 11.5:1 when in boost. AWESOME!
Glad to hear it worked for you. It's a simple and basic system, but it works so well on these cars. Using it, and a couple more PSI boost, we went into the high 12's @ 106 on an otherwise 100% stock car with slicks...even overweight with sound system and airbag suspension!
Thanks for choosing Hahn
Bill Hahn Jr.
Hahn RaceCraft
World's Quickest and Fastest Street J-Bodies
Turbocharging GM FWD's since 1988
www.turbosystem.com
