97 LT1 running rich I'm getting pretty fed up..

97 LT1...   LTFT's sitting at -16..  I CANNOT figure out what is causing it..  HELP!!??  You name it and it has been checked / replaced...  

I have a little bit of info that may or may not help you. Remember lean is MEAN, but dangerous. May current flash is set to 11.7 which is conservitive meaning more on the rich side. 16 is way to rich you need to go have your ECU flashed and reprogrammed for fuel changed. Hope that helps.

MattGLT1  

I have a stock LT1 1995 TransAm , no modifications.

It is running rich.  Although not horribly rich, the exhaust looks normal except water should come out the tailpipes, instead black water comes out the tail-pipes.  I know it`s running rich, not too bad.

It has had a recent tune-up.  I replaced all sparkplugs with factory AC-Delco platinum tipped pre-gapped plugs.  

The motor is running smoothly, however it is running rich.  I do get a warning light VERY OCCATIONALLY, the warning light comes on only sometimes, and from hearing the motor you can't tell that anything changes when this happens nor can you tell from hearing the motor that anything is ab-normal.  In fact since changing the plugs the motor is running very smoothly.

However, it is still running rich, I know this because of the black water that comes out of the exhaust.  The exhaust does not appear to be rich from appearance , other than a slight richness smell to it.

I bought the car in June

The motor puts out LOTS of power even though it's running rich however I know that it could be better if I was able to solve this problem.  

I checked the codes from the computer and it said something about bank 0 oxygen sensor, however the dummy light doesn't come on very often and this is not a solid code.  So I think the oxygen sensors are still ok, however not sure.

MattGLT1 says that the ECU can be flashed and reprogrammed for fuel changed.  Is there anyone in the Ottawa area or near by that may be able to help me read my ECU and help me diagnose this , or adjust the LTFT ?   Perhaps to 11.7 or lower, I'd like to see what mine is set at.

I've burned 94 octane fuel in the car, it's readily available at the pumps

there's also 91 octane available everywhere.  

Do I set the ECU with 91 octane in the tank?  

I don't want to buy a computer reader for ODB1 because they cost $400 , but I also don't want to have to pay $100 each time I want the computer system read.

Anyone have any advice to getting my LT1 tuned-up relatively cheaply?  

I've checked for vacuum leaks and there doesn't appear to be any.  I previously had re-attached a dongle after the mass air-flow sensor which WAS disconnected when I bought the car, I also patched a very tiny hole on the rubber piece leading into the air intake, so that's fixed.

Air-cleaner is recently changed but I'm going to change it again.  I also inspected the mass airflow sensor and it appeared in prestine condition.  

I hear there is a diagnostic tool that some garages have , $5000 for this computer that can get feedback from components of the car, it would be nice to have access to one.

Any help or advice is appreciated.  

previously my LT1 did throw a MAF code for mass airflow sensor, but I believe that has been fixed.  I re-attached a dongle that was not connected (after the mass airflow sensor) and patched a small hole.

I'm wondering what the factory ECU settings are, and how I would check this, I'd like to have my car chipped to factory settings, or if possible maybe even slightly tuned setting (if it helps)

Main problem I am concerned about is richness.  it's too rich right now, black water out the exhaust , rich odour to exhaust however the color of the exhaust is colorless, or perhaps slightly black although at idle I cannot tell.  I did record video footage of the exhaust while revving to 3500-4000 rpm and there was slight blackness to the exhaust.

I know it's running rich, not horribly rich, but significantly rich, enough to notice it if you know what you're looking for.

Help for me near Ottawa?  Or perhaps advice?  

Actually, I did some more reading.

My computer throws oxygen code bank 0

It seems that richness is most affected by a bad oxygen sensor.

I will replace the oxygen sensor but I have to figure out what bank 0 is, is that drivers side?