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Discussion Starter #1
I am trying to do an E85 speed density closed loop tune on my OBD1 (1994 ECM) swapped 1996 Camaro.
Do the narrow bands read E85 the same as gasoline? I am having idle issues. If I set the IAC/TPS to start up and idle with the car cold in open loop, when it gets warmed up and in closed loop the idle shoots up to 1600-2000. When I set the IAC/TPS for it to idle warmed up in closed loop then when it is cold and in open loop you have to hold the throttle open for it to start and hold throttle open as it idles, until it gets warmed up before it will idle on its own. I put the MAF back on it and loaded my old MAF gas tune and put the injector constant at 42 (60 lbs injectors at 55psi fuel pressure). It did the same idle issue but it revved way better, nice and smooth, than any of the speed density tunes I have tried. This was the MAF tune the car was on before I had intake ported, put on 58mm TB, and switched to E85.
I did notice in the data logging software (EEHacks) is showing -20 to -30 BLM at idle when it hits closed loop, which would indicate it is rich, but the wideband is showing 19-20 AFR but I heard that is common at idle if the wideband is in the exhaust pipe. But that does not seem to change if I lean it out or richen it up. What am I missing?
Do people typically tune E85 for closed loop on these cars? Seems as though something is happening when it gets in closed loop. Should I pay no mind to the wideband and keep leaning it out until the BLMs do not show -20 to -30 at idle? Or should I just do Speed Density Open Loop tune and go off the Wideband?
Car Details
383 cubic inch LT1
E85
1994 ECM
160 t-stat
12.5 compression
Stock Ported LE2 Heads
LE2 Cam 244/[email protected] .614/.620 Lift 110 LSA
LE Ported Stock Intake
60lbs Siemens Deka Injectors
Fuel Pressure 55psi
Professional Products 58mm TB with IAC passage mod so air goes into bottom of intake as it should
Long Tube Headers, duals with bullet mufflers
Underdrive Pulleys
1.6 RR
Homemade (over the radiator) Ram Air Intake Setup
All Emissions Deleted
 

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132 Posts
Discussion Starter #2
I ignored wide band and tuned the BLMs to within +5 to -5 and it idles good in park and gear in closed or open loop now.
 
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