So I was able to tune the VE table to where I was pretty happy with it. This was all done in one day, so same appx air temperature and coolant temperature. Car was running well, attaining commanded AFRs across the map (using WB verification).

However, after sitting for a while, and once the outside temperature had cooled some, the car was running lean until warmed up. I was able to reproduce again today, with much cooler outside temperatures.

Any suggestions on where I need to look for compensating for this?

Thanks in advance!

 

You're running a RamJet manifold.

What does your air intake set up look like? MAT sensor location?

If you've relocated the MAT, you're going to have to alter the tune to account for that.

 

Thanks again for stepping in to help, ULTM8Z.

I'm running a filter right on the TB, and the MAT sensor is installed in the back of the manifold.

 

Pic attached

 

When you say it was "sitting for a while", does that mean until the engine cooled down?

What was the coolant temperature when you started it back up and it was running lean?

 

This^^^

May need open loop vs coolant temp adders increased

 

Yes, the engine had cooled down. I don't know what the temperature was, but probably around 66* when I did it today, since that's what ambient temperature is and it had been sitting all day.

I did try bypassing table L880E (MAT Inverse Term Lookup Delta Mult. .vs. Airflow ) and that definitely seemed to help some. I'll try again tomorrow when I know the car is fully cooled down.

Although it's labeled a little differently in the SAUJP v5 XDF, I seem to remember that this switch at L8018 tells the code to use either the intake air heat-absorption 'model' for the intake tract, or uses the MAT directly.

Doing this did affect WB AFRs elsewhere in the RPM vs MAP spectrum, but if it's a matter of re-tuning the VE then that's easy enough.

 

From what I can tell from the available tables, they all tend to enrich by a certain %, which means the commanded AFR would just be richer.

Although I could simply make it ask for a richer AFR, is it normal to have to ask for a lower ratio than you want to achieve? I kind of feel like it shouldn't need to be 'fudged' but maybe I'm totally wrong in my thinking...

 

Nothing wrong with simply modifying the coolant table for open loop to get a richer AFR.

I think for MAT sensor in the manifold, you need to have the Inv MAT table enabled. That could also be the source of your lean condition. For MAT sensor in the manifold, that table supposed to take into account how fast the air is moving through the mainfold in order to determine the coolant temperature contribution to the final air temperature.

Maybe try re-enabling that before doing anything else and see what happens.

I disabled my Inv MAT table when I put the MAT sensor in the air duct.