I recently changed over to sd using the 90550001 on a E7 ecu,

The issue i am having is a splutter,jerking on very light throttle at around 2-2.5k revs in any gear and no matter what adjustments i make i can seem to get rid of it

The car drives fine on boost and normal acceleration its just the very light throttle that is giving me issues any one have any ideas what i could be

 

Sounds like the same issue I was having when I originally tested the SD patch.

Noticed on my wideband at the exact same time it would splutter the afr would dip into the 16's / 17's for a split second.

 

The fueling seems fine when this happens that's the issue

 

hopefully someone can help, as I really wanna switch mine to SD again now, but don't have the time to mess about with it endlessly to get it running smoothly

 

I have it too. My tuner tried smoothing it a little, but I still have it. Its something I've learned to live with

 

This has been fixed. Search for IPW jitter and that should lead you to the threads. mrfred posted 3 fixes for it. I think the majority are using fix #2 or fix #3.

 

Yeah I'm using fix #2 at the moment, seemed to work the best for me. Will the tables listed be the same for his rom though? AFAIK mrfred only posted them for 9653...

 

I have tried fix #2 and i seem to improve it slightly but its still there

I would like to know this also as i am using the 9653 address to carry out fix #2 on 90550001

 

umm i had that prob with maf and i made alot of changes one time and accidentally corrected it.. turned out timing in the low load cells were too low (retarded them for flames... smh) so i put it back to stock and upped it a bit from there.. make sure yours isnt retarded.

 

The timing is not retarded in the effected cells

 

Well i've been out playing today, and just like jamie v1 I have the same issue, between 2000 and 2600rpm the car starts to splutter and cause the car to judder.

I have also used fix 2, seems that fix 3 isn't defined for 90550001 at the moment.

 

whats your RPM vs VE table like?

 

Here you go

 

Can you post the area of the log that shows the issue.

I have seen some of Jamie's logs and I'm not quite sure if it's the same SD jitter as I have logged in the past, that was corrected with mrfred's fixes. His IPW did seem a bit jumpy, but nowhere close to what I had logged in the past. I had only tried fix #1, right after mrfred posted it, and I posted screenshots of before and after, showing the IPW jitter completely gone. I didn't get a chance to test #2 or #3 yet.

I did look at this ROM in IDA, and although I'm not a disassembler, the first two fix addresses looked to be the same addresses as for 9653xxxx. Fix #3 is not, and I don't know the address.

Do you get the issue at a constant throttle or only when coming back onto throttle after a decel fuel cut? I think Jamie is only getting it right after getting back on the throttle, so it may be related to async or sync accel tables.

Have you tried fix #1 and does it do the same thing? Maybe mrfred can verify the addresses for this particular ROM.

 

This is probably the best 1 I have, as I got bored with the car stuttering with the other logs and started to go WOT

It seems to be there upto 2700rpm, on a steady light throttle.

Haven't tried fix 1 yet.