Hey Folks, I guess its been a few years now since I came up with some possible patches to try to fix the SD stutter issue that people were having during off-boost driving. I haven't seen much discussion of the stutter issue in the ECUFlash forum recently so does that mean that the patches fix the issue?

 

I have not had any, but it would be nice for some of the viii sd roms to be cleaned up, like the 2 step not working on some and nls.

I know your the man with this stuff.

 

I experience it occasionally.

 

Which of the options (1,2,3) are you using? Have you tried them all?

 

The fixes completely cured it on my car as well as many others that I've set up.

 

I had it real bad in 8859 which I never saw a patch for. I don't get it at all with 8858. Both sd 2.0 roms

 

My friend has some issues but it's partially stutter issues and stalling out while taking off. I believe the stalling I can fix with the asynch vs tps. Just gotta play with it to find the good setting.

MrFred, I haven't messed with the fixes to see what one does what. Have you declared what setting fixes which issue? When I went to go tune SD, I found myself guessing on the fixes.

 

Have you seen the three fixes that I wrote? They are simple 1D table patches. The first two should nominally address the same issue while the third fix addresses a different potential issue. The reason that I started this thread is because I am looking at a fourth potential fix, but it requires a brand new SD patch rather than something that can be added onto the existing patch.

 

I got tuned on my 2.3L a few month ago, and had the issue really badly. My tuner said he's tried everything. I'll have to research my rom when I have a chance to follow up on this thread.

 

Actually no I haven't. I'm going off the ones provided in V7. I will look into your patch.

As for the new one, what you got in the bag? Or is it a secret? If it has to be a brand new SD patch, you're looking at re-writing the whole SD script, right? Wouldn't work with the SD 2.0 3D maps?

 

All the existing stutter fixes are ones that I wrote. If there are any in your V7 xml, they will be mine. There should be three.

 

I think the stutter is an accepted risk and most do a decent job avoiding it. For me with lots of rural driving I couldn't deal . It's wired how inconsistent the problem is

 

mrfred,

I'm going off of my memory here, but I remember I was one of the first to notice and show logs of this when I went to SD.

I could have sworn that one of your fixes eliminated the issue, at least on the 9653 rom. However, this is at least a few years back now, as I switched off of SD because of the minor annoyance of heat soak of the sensor for startups.


Eric

 

Eric, yes, it was your posts that got me going on the stutter fix. I thought I had covered all the possible contingencies as well, but there have been reports of it since then. Perhaps some people are not aware of the fixes? Or perhaps its just poor tuning? Or maybe there is more to it?

At any rate, a fourth possible fix does exist, and that is to insert the SD master load in the exact spot where the baseline MAF master load calc is completed. Three additional calculations would be performed on the SD master load if I put it here:

1) There are two algorithms that alter the master load calculation to help deal with abnormal spikes in load or perhaps fault conditions. They are not averaging routines but rather limits on how much the master load can change under certain conditions.

2) The SD master load would be run through the master load running average algorithm.

I think that John Banks would say that in his experience, this is not not necessary and may be why he didn't do it, however, I see value in placing it before the master load running average algorithm.

 

Makes sense and I do remember John mentioning something along those lines and not needing it, due to his experience on his ROM. But perhaps to cover all ROMs, your new method would be the best approach.

So back to your original question starting the thread - see if people still have the issue with the previous fixes.