View Single Post
Old 01-20-2013, 06:59 PM   #14
Registered User
Join Date: Nov 2009
Location: Fairfax, VA USA
Posts: 16,585
My Ride: 330CiC, M5, X5
I am a bit confused about about a few things based upon your graphs.

Maybe you can add more detail for me about what is going on.

Assume your horizontal axis scale is in minutes?

Anyway around 20 on the horizontal axis your throttle position crashed to 0 and stayed there. Did you back off the throttle and coast down a long grade? Or is something else going on with the throttle position data as the engine RPM never seemed to drop below about 2300 RPM??

Between 16-21 on the horizontal axis for Ignition Timing you had some dips.

Can you regraph the Ignition Timing for this time frame with a total scale of about 10 degrees? I want to see how much and how rapidly your timing is dipping. This timing dip may be justified, but it may also be what you are feeling with the power instability.

Can you rescale Bank 2 Fuel Trim to be +/- 20 even if it pops off scale briefly, I want to compare the slope to Bank 1 on the same scale.

I may also need to see your long term fuel trims as well.

Note sure the Fuel Trims look correct?

Need to get a better look at the O2 sensors and make sure things are plugged into the proper bank and there is not a lazy sensor.

I find it best to graph O2 sensor Voltages from a cold start so you can see the baseline O2 sensor Voltage and the warm up cycle into the switching cycle.

See what you can do with O2 sensor graphs. The O2 sensors can usually be ruled in or out as a problem pretty easily with graphing from a cold start. Unfortunately MAF testing is much more difficult and subjective.

Once we know the O2 sensors are behaving as expected, then we can move onto other areas.
Solve your misfires, lean codes, rough idle -

Fuel pump failures -

Temp Info -

Hidden OBC Menu - Check Voltage, Temp, Fuel Level -

E46/E39 GM5 Door Lock Info -

Lower hose temp switch O-ring - BMW #13621743299
jfoj is online now   Reply With Quote