tdr1919

I ran my 86 out on the hwy for a good 45 minutes and recorded the session. I was trying to understand the histogram, the fuel cells were mixed white and light green, some dark green no red. the notes state white is optimum fuel, green is lean. if the cells are green, does this mean the ECU will try to richen the mixture to bring the cell to white or optimum mixture. Or is this just saying the that it running lean and is OK.
Thanks,
Tom

JackDidley

The integrater, short term numbers are the ecm trying to correct the lean cells. There is a limit to what it can do here. If you have an adjustable fp regulator you can bump up the pressure and see if it helps.

tdr1919

Thanks Jack for the reply, I am trying to understand what is good or bad results. If the the engine is running correctly would I expect to see all white cells? are green cells a better cituation than red cells?

I failed emissions for HC (almost double the limit) the mechanic said it was either running rich or a bad catalytic converter. That is what prompted this test.
Tom

JackDidley

I dont have emissions so I dont know what to say on that. A little pale green or a little pale pink wont hurt the motor. All white is theoretically the best but my car seems to run and drive better a little rich. Maybe post this in C4 Tech and more guys will see it and add some advice.

rodj

If you have the histogram up when running a log you will see the colors change in the cells as the engine runs.
The color you end up with is a average so 5 reds and 5 greens would give white even though that cell was rich and lean at times ( highly unlikely )
If you click on a cell you can see how many times that cell has been hit on during the log

tdr1919

Thanks Rod,
On the long term, if the cells remain green, is that telling me that the ECM will be constantly trying to richen the mixture?
Thanks,
Tom