i am have a problem tuning my fuel map in calmap v6.32.no matter how much fuel i pull out its still rich.i THINK i have an exhaust leak causing the o2 sensor to add fuel.my question is should i set the ecu for open loop, and then tune my map from there?cause it might be a while before i can fix the exhaust leak.plus i am getting a backfire from the exhaust,i think thats happening cause its too rich.,am i right?any help would be appreciated...
mike

 

Could also be a bad O2 sensor. I once put a custom exhaust on my blazer, and the exhaust shop welded the O2 bung really crappy, so the O2 was barely in the flow of the exhaust. As a result, the computer started dumping fuel in the motor because the sensor started reading lean. Try explaining that to exhaust shop guys who keep insisting that they've done it that way a thousand times.

Anyway, if your O2 is clogged up or dying, it could be reading artificially lean by itself.

Teeleton

 

hey thanks,but the o2 sensor is new.

 

The best way to tune is in open loop with a wide band. If in closed loop tuning part throttle, the bar graph at the bottom right of the base fuel map will show you where you would be in open loop, i.e. either rich or lean. Use it as guidance to get you close.

 

emtcee - I'm surprised that you are still running rich. Did you pull the 10% fuel out? Try going to the global menu and switching to open loop this way the 02 is not controlling anything.

You really need to get a wideband 02. This is the only way for you to get a true reading.

If you've been running rich for a while, change the plugs. This may help.

 

hitech,
yeah i pulled 10% out and its still rich.that what i was going to do(set the ecu to open loop).and i just bought new plugs cause mine were black.as far as the wide band o2 i need to save a little more cash and get the lm1 unit.really haven't been able to work on the car cause its been cold as hell here in jersey, plus the snow.i really need to move to somewhere warmer.thanks for the relpy.oh yeah i do have 30lb injectors(383 stroker), do u think those injectors are too big?fuel pressure is @ 43psi.thats the lowest my afpr will go.

 

I used 30# injectors on my 383 with great success. This was however with the MiniRam manifold solid roller cam etc. When I had a SuperRam, I used 26# injectors. If I recall correctly, you have SLP runners? If your motor will not see over 5500 rpm, you may need to size down the injectors.

For now, I would leave the fuel pressure and continue to pull out fuel. Can you send me a copy of your file? I would like to see where you're at compared to the original I sent.

 

hitech,
i will try t send u the file tonite if i don't work late,otherwise i will send it tomorrow.and thanks for the help.
mike