Tuning Progress - Finally have a decent bin thanks to 3rdgen and FB site help.

Car is civil to drive but feels like it still has along way to go.

Running NB learns with the majority of corrections in the 10% area, this after completing the fourth NB learn. When should I stop NB learns and switch to WB learns?

Also, on decel at any speed engine feels like it wants to kill like an engine braking feeling. What should I look at /adjust to improve this?

Thanks.

 

My tuning has taken a turn for the worse - here's what's going on - While reviewing my data logs I noticed that INT (short term fuel trims) progressively get lower (sensing rich conditions). Yet each new "learned" bin is leaning the VE's. As a result the ECM is pulling more and more fuel from leaner VE's and the car runs worse with each new learn especially under load.

So, tunes are going backwards in a sense. I believe the same thing was happening last summer but couldn't put my finger on it. Think if I can resolve this issue I'll be on the right path.

Defective ECM ? Doesn't make any sense that leaner VE's get leaned out more....

 

A silicone poisoned O2 sensor will do that. Reports rich which drives the fuel trims down.

Look at the log and see what the O2 sensor is reporting.

RBob.

 

Last data log - With INT's around 97 WB AFR read is 15.5. Also DE is kicking in...

Also noted - respectively TPS/DE/INT/AFR reads 13/Y/123/14.37, 14/N/121/10.6, 39/Y/105/11.3, 34/Y/96/13.5, 30/Y/113/14.2... Do you see somethings here that indicate a bad O2? Or is more data needed?

 

Here it is graphed.. Look like a bad WB? Can see how it's running via RPMs at leaning.

 

Need to look at the NB O2 voltage, that is what the ECM is using for the fuel trims.

A screen shot of the analysis display is more useful.

DE (decel enleanment) is used during a throttle lift. That flag is also active during DFCO.

Also, it looks like there is too much AE, note at the beginning of the graph when the TPS goes from 12% to 39% the reported AFR goes rich.

RBob.

 

Replacing my WB.. I see you're out of the TT-1 package. Can you recommend an alternate WB set-up?

 

Have you checked the NB O2 sensor voltage in the data log?

RBob.

 

I believe it's simulated by my Zeitronix WB. I'm only running one O2 sensor.
Will post log....

 

Here's the data log right at the point of the erratic running issue. Again the NB is simulated - a fact I wasn't initially aware of... I do intend to add a unique NB to my set up. Anyway, response consensus is WB looks defective as this data is reviewed. ?

 

A dedicated NB O2 is a good idea. The WB may be misreporting toward the rich side. As the reported AFR in the low 15's shouldn't cause much of an issue (other then some power loss). As that is easily within the lean cruise range.

RBob.

 

tThanks I'm going to replace it. Any recommendations? Looking at the Zietronics Zt3 kit - assume that would work.

 

The ZT3 will work.

RBob.