The Z has been running very rich since I put the cam in. I had it tunned by pcmforless. I was thinking my o2s were bad so i plugged in the laptop and logged a drive using TTS datamaster. Both o2s were bouncing around like normal, except at wot they both shot up to 950 mV and stayed there untill i let of the gas. This happend every time i went wot and the o2 mVs never leveled out ant any other time. Is this normal?

Also if it isnt the o2s, what else should i take a closer look at?

 

At WOT, the PCM does not use the 02s, and instead uses the logged long term integrators for fuel delivery. This is normal.

 

Well i just spent some time looking at the file again. While the car is still in open loop, the BMLs are right at 128. When it goes into closed loop, the BML's and fule trip cells start going nuts. They go way rich. Does this mean the car is only running rich in closed loop, or just that i dont know its running rich until it hits closed loop? Teh BML's droped below 100 at somne points. This happend at all speeds and rpms - Thanks

 

...also... when in open loop the o2s bounce around a little, but when the car hits closed loop, they start bouncing up and down 100 times as much!

Also when i input the data from the short and long term fuel values (BML) and graph it against the charcoal canister purge duty cycle, the A/f ratio becomes considerably unstable when the canister is in the duty cycle. Are they related?

What the heck is going on? - Thanks

 

http://members.aol.com/InjuneerZZ/ScanMast.htm

Have you read this? If not this will answer all your questions.

 

The fuel trim cell # changes because that is the storage space for the BLM for the particular RPM/MAP your engine is operating at, at that particular instant. There are 18 "cells" and the cell # is going to change as you move the throttle, change engine RPM or change engine load (MAP).

Yes, the O2 sensors will start at 450mV on cold start, and gradually drop to 00XmV. At that point, the PCM will go into closed loop and shut off the AIR pump. Now the O2 sensors will change about 9 times per second. That is how the A/F ratio is held very close to 14.7:1 for idle and low to moderate loads.

You need to look at your long term fuel corrections (BLM) for each cell. If your "high load" cell in closed loop is adding fuel, the PCM will use that BLM at WOT. If the high load cells are cutting fuel, the PCM will use 128. In any case, there is a good chance that if things aren't set up properly, it is going to run rich.

Get as many combinations of Cell # and right and left BLM's as possible. That will tell you where your tuning is goind bad. Of course it isn't always "tuning", it could be exhaust leaks, misfires ore other factors.

Yes.... read my online "Scanner" writeup, linked in a post above... .