Fiero Projects

Purpose and Reason for data logging


To improve 3.4L engine performance. I have had the 3.4L engine in for a while and I have made small attempts to tune it. I will make a serious effort to increase performance with measuring what is happening at the ECM.

The Plan

Each time I go some where in my fiero I will take my laptop and connect it up and log the data. I have written a small program to put a time stamp infront of each entry. The time stamp is milliseconds since the start of the data logging.

Feel free to look at and help me evaluate the data below. If you have insights on some change you think I should make send me e-mail

The Data so far

click here for data files

Interesting data plots

A plot of tps vs. map. This shows that the fiero intake is indeed not flowing enough air. As seen in the plot the engine is keeping the same vacum level from a little past half tps to full tps. This matches with the feel of driving the car. From half throttle to full throtle there is very little change in power.

Emission testing results

%CO2 %O2 HC (PPM) CO(%) NO(PPM)
Test rpm meas meas max ave meas max ave meas max ave meas result
15mph 1871 14.9 0.3 221 45 14 1.13 0.20 0.0 2177 530 816 PASS
25mph 1871 14.9 0.3 206 23 15 1.03 0.09 0.00 1977 368 820 PASS