I don't seem to be able to get past this nasty stumble at the low RPM (1000-1800) range.

I have this problem in all gears, and apparently most loads.

My VE tables look really good around 126 - 128 at these RPMS.

I just keep thinking it is a spark issue.
Given the nature of my induction and the size and type of engine, I am not sure which way to go. I keep thinking I should have more torque at these RPMs but there isn't as much there as I would have expected.



When I bring the spark timing down, the engine has less power and will buck until around 2000 rpms.
Could I simply be giving it too much fuel and need to retard the spark?

When I retard the spark about 3 degress, My BLMs sstart pulling out fuel, and the whole things seems to run too rich even in AE. Is this the case? I seem lost.

Thanks

 

You might try not ramping out as much timing off idle, and adding the necessary fuel to tun that timing in the VE table.

It's awkward to try and add enough AE *just off* idle.

And you might want to drop the lower PE TPS enables (if you code has a 2d TPS PE Table), so you don't have to run alot of AE.

 

Thanks for the reply, but I don't understand what you mean.

"not ramping out as much timing off idle"
Should I add more timing around the 800 - 1200 rpms?
Then add more fuel in these ranges as needed for the VE?

Lower my PE TPS thresholds to 50%? It is currently at 70%.

Does this Spark Table seem OK for a Heavy Manual truck?

 

Should I be comparing my spark table to the AXCN? (this spark table seems too high)

Or maybe the AUJP? (this spark table seems VERY low)

 

Cut and paste your table into a post, and I'll demonstrate what I mean.

Might also do the same for your VE.