noob trying to learn e38 l76 cam swap stutter/lean state

[ineptmath]

sup guys, trying to tune my first car running into a lean state that causes some violent stutters, when going through car parks, or taking off from a stop,
i would really like to do this my self as ive taught my self alot of the mechanical side of it (3rd car engine finished 1 complete rebuild from small block) and would like to be able to understand all this better i know time relatively = skill just very cautious and second guessing my thoughts

ive tuned MAF. im trying to tune VVE just second guess my self alot as im a nub any input greatly appreciated thanks.
6.0l l76 cam swap (dont have specs) everything else stock m6 e38

im currently using goat ropes method to tune the VVE but it didnt feel good driving and just worried im going to break something again any input greatly appreciated ive been reading for a close to a year but finally got headers to put a wide band in and am trying to tackle it thanks heaps.
ive read about smokeshow's or cringers methods but i cant connect the dots that well as i need the idiots complete guide to show me how to set it up correctly.

lastly am i correct in thinking if i get the VVE table completely finished tuned and then work on the spark timing will it fix this issue or is it one of these underlying tables that works off of other stuff using co efficient and what not. again thanks.

[biholliday]

looks like you have bumpy maf syndrome. i would suggest for you to look up silversurfer77 on yt. There is a whole bunch of vids that you will be intersested in that will help you.

[Alvin]

What is the entire setup? What cam?

I see it a touch lean on the wideband but nothing that should cause issues like you are describing.

I don't know what MAF you are using but most of them in later GM's have no screen/card style so how they are welded in/mounted is a huge variable. For most swaps I will not use the MAF even on stock cammed stuff. I find doing them in strictly in SD will give better driveablity.

I'm not sure what goat rope teaches but I only recommenced completely failing the MAF and tuning the VVE by itself. Then reenabling the MAF if you wish.

[Cringer]

sup guys, trying to tune my first car running into a lean state that causes some violent stutters, when going through car parks, or taking off from a stop,
i would really like to do this my self as ive taught my self alot of the mechanical side of it (3rd car engine finished 1 complete rebuild from small block) and would like to be able to understand all this better i know time relatively = skill just very cautious and second guessing my thoughts

ive tuned MAF. im trying to tune VVE just second guess my self alot as im a nub any input greatly appreciated thanks.
6.0l l76 cam swap (dont have specs) everything else stock m6 e38

im currently using goat ropes method to tune the VVE but it didnt feel good driving and just worried im going to break something again any input greatly appreciated ive been reading for a close to a year but finally got headers to put a wide band in and am trying to tackle it thanks heaps.
ive read about smokeshow's or cringers methods but i cant connect the dots that well as i need the idiots complete guide to show me how to set it up correctly.

lastly am i correct in thinking if i get the VVE table completely finished tuned and then work on the spark timing will it fix this issue or is it one of these underlying tables that works off of other stuff using co efficient and what not. again thanks.

I would suggest adding two more PIDs to your channel list:
Fuel Trim Cell (PID 6310)
Volumetric Efficiency Airflow (PID 2311)

Then post a new log with that info.

[ineptmath]

@Alvin - i didnt get the cam specs in this motor was my first swap was scared to open it up regret that now. yes i rewatched log and noticed it didnt really show it apologies my bad ill try get some more data tomorrow.
yes failing the maf and driving it off the vve table, thats the method im doing at present just felt the motor have a stutter and got worried after reading something about SD, ill continue.

@cringer yes i will do that and go for a drive tomorrow, I'm just in the process of reading your threads and trying to piece together your videos.

--cheers

[ineptmath]

hey sorry didnt get a chance to do that today had kids and other stuff on, i did just go for a two hour drive to get this VVE dailed in. screwed something up in my PiD's so after the first hour no data in my histogram, second hour i got a good chunk of good data i believe. just going to try figure out the vve assistant and figure it out now.

on another note i did do some carpark driving and yes the stutter and surge is still there in 1st/2nd trying to coast through a car park ill cut logs and upload shortly thanks guys


just went through the log its not really giving me anything and i lost the 2 pids you asked me to log with the hiccup i had, ill do it tomorrow sorry about that

[ineptmath]

@Cringer ok i logged just the stutter this is in open loop but essentially same issue (very violent jerking unless i manually power through it and open up the revs a fair amount) if im running off maf let me know if i should change it for you i also logged the 2 pids you requested cringer.
im terrible sorrry if its staring me right in the face im just very blind at present but im slowly increasing my knowledge base. also took a log with traction control off as i thought it maybe a contributing factor. it wasnt

dunno if my vve is any better i tryed using cringer tool on the data i collected.

thanks for any assistance i think i need 2 more logs to tune vve in a little more on high and low rpms then ill put the spark back in and start tuning that then move onto torque and see if that helps

just a thought here, is any of that data indicative of it not getting enough air at that zone? im just trying to recall at one point i had a TB with a hole in it and my idle -> airflow -> effective area -> percent max/percent max brake where 2% higher i just cant recall if i had this issue, i changed that intake because of a different issue.

[ineptmath]

ok so hopefully this is not placebo i did 3 runs up the street and prior to this i was able to replicate the violent jerking on demand. ive raised the idle-> airflow-> effectives a few %
i raised the airflow minimm a good chunk and tuned the torque follower.
i will test again more thoroughly later tonight and add the timing back in and bla bla bla.

so i know what i physically changed but what did i really tell the engine to do ? my lines of thought were. i was seeing 10g of air on the dynamic and maf when it was in this jerky state and i was thinking ok eq ratio is .98/1 but thats a ratio on 10g instead of 14.7 so i tried to raise my air at that rpm/conditions

is that what i did ? i would still like to raise it a few more grams as its reading 12ish , am i correct in thinking i raise my airflow minimum in that rpm ?
then to dail the vve in at that rpm im just going to go to a quiet dead long ass street and let it barely idle down there a few times to get my data correct ?
thank you in advance.

[Cringer]

@Cringer ok i logged just the stutter this is in open loop but essentially same issue (very violent jerking unless i manually power through it and open up the revs a fair amount) if im running off maf let me know if i should change it for you i also logged the 2 pids you requested cringer.
im terrible sorrry if its staring me right in the face im just very blind at present but im slowly increasing my knowledge base. also took a log with traction control off as i thought it maybe a contributing factor. it wasnt

dunno if my vve is any better i tryed using cringer tool on the data i collected.

thanks for any assistance i think i need 2 more logs to tune vve in a little more on high and low rpms then ill put the spark back in and start tuning that then move onto torque and see if that helps

just a thought here, is any of that data indicative of it not getting enough air at that zone? im just trying to recall at one point i had a TB with a hole in it and my idle -> airflow -> effective area -> percent max/percent max brake where 2% higher i just cant recall if i had this issue, i changed that intake because of a different issue.

This should help you. However, these logs are not really good enough to tackle VVE (or MAF). You need at least 30 minutes at the MIN of closed loop driving after the ECT and oil are at full temp. 45 minutes is good. 60 minutes is better. And drive with a slow and steady throttle input. No violent stabs. Hit as many different cells on the VVE scanner chart as possible and hold each cell as long as possible.

Flash this tune and you should see improvements.
ve ss sd vve step 4 - cringer .hpt

[Alvin]

This looks like a solid miss, prehaps a bad injector on the passenger side.

final Timing and fueling are reasonable and shouldn't be causing that.

[ineptmath]

@Cringer tried it mate thank you very much for trying, it was still violent stutter i didnt log it sorry, was in a race. ive tuned it out on my current tune how why dunno apart from my previous posts statement which i have no doubt is completely upside down.

@Alvin im in AUS so im assuming you mean bank 2 ? i shall investigate.

just got to go through some logs now and will post up after i have a go at looking for stuff to fix.

since swapping this engine(cam) ive noticed gear 1-2 feels very weak from how it used to pull with stock cam/engine am i right in thinking i can strengthen that area by advancing the spark ?

at present im working on spark timings im basically advancing logging and subtracting the knock.. if its not knocking keep adding ? then what type of driving am i ment to be doing i was doing some normal driving + hard pulls on a old back road hardly used

will update post with logs after i view them and make sure im learning something cheers.

reference pull, i can see that it doesnt look right but im still trying to understand all the ins and outs, if some one may could u please tell me what is happening there, that is 1-2-3 should be wot at the end.
its hard to fix stuff when im stilling trying to learn to read whats broken thanks.

[Cringer]

If it is a bad injector, you can use the scanner to turn off each injector one at a time. When you do so the engine should run worse. However, if you turn off an injector that isn't working in the first place, then no change should occur.

[Alvin]

In the pull log I saw no indication of a miss.

It's rich with low timing for a NA LS vehicle. It has room to pick up in the tune.

Generally your plan of if no knock then add timing is a OK plan. Listen for actual knock. You might not pick it up with sensors.

[ineptmath]

In the pull log I saw no indication of a miss.

It's rich with low timing for a NA LS vehicle. It has room to pick up in the tune.

Generally your plan of if no knock then add timing is a OK plan. Listen for actual knock. You might not pick it up with sensors.

thanks will work on fixing it, i used another timing table i had from donor car and it made good power in those areas i was worried about. but introduced the stutter back.. i will keep working on it thanks for the sound board and ideas has been a tremendous help @cringer @alvin and eleviated alot of the self doubt i had on things. now i feel asif each time i read a log i see a new bit of information that i can use and slowly am able to filter said data into useable data(don't get me wrong still a small ameba in a big pond) ill post some results when i get time need to get another vehicle ready for an inspection on monday.

[StraightShot75]

sup guys, trying to tune my first car running into a lean state that causes some violent stutters, when going through car parks, or taking off from a stop,
i would really like to do this my self as ive taught my self alot of the mechanical side of it (3rd car engine finished 1 complete rebuild from small block) and would like to be able to understand all this better i know time relatively = skill just very cautious and second guessing my thoughts

ive tuned MAF. im trying to tune VVE just second guess my self alot as im a nub any input greatly appreciated thanks.
6.0l l76 cam swap (dont have specs) everything else stock m6 e38

im currently using goat ropes method to tune the VVE but it didnt feel good driving and just worried im going to break something again any input greatly appreciated ive been reading for a close to a year but finally got headers to put a wide band in and am trying to tackle it thanks heaps.
ive read about smokeshow's or cringers methods but i cant connect the dots that well as i need the idiots complete guide to show me how to set it up correctly.

lastly am i correct in thinking if i get the VVE table completely finished tuned and then work on the spark timing will it fix this issue or is it one of these underlying tables that works off of other stuff using co efficient and what not. again thanks.

hey buddy, look up a cperson named Matt Stanford AT skyTUNING.COM . HE IS ALSO ON YOUTUBE, BUT HE CAN DO like a consultation w you for not much.

[ineptmath]

hey mate, thanks for the reply. i think ive got a handle on it ive just tuned another car (didnt say well) but i feel like im getting alot more familiar with the data. i will look at the videos once i get some time thank you again.

[ineptmath]

so ive rescaled idle perc max + brake max back to close to stock or how i found the car. retuned braf settings to close to where i want

my issue now is that im seeing the spark get changed over to the minimum spark tables at coasting/idle moving in 2/3rd gear minimum being 3*. id like to know why?
in order to find that id love a clue as to what to log or look for to figure that out. ive pulled a heap of timing out of current tune whilst i was trying to fix issues. cheers for any advice and critiques. in current tune ive got it set to maf only or primarily as i was trouble shooting. its the same when i have it scaled correctly to run off the vve in the lower revs

currently logging spark torque management type but its showing me none

this is just an idle up and down road whilst im trying to figure out issues

[Cringer]

so ive rescaled idle perc max + brake max back to close to stock or how i found the car. retuned braf settings to close to where i want

my issue now is that im seeing the spark get changed over to the minimum spark tables at coasting/idle moving in 2/3rd gear minimum being 3*. id like to know why?
in order to find that id love a clue as to what to log or look for to figure that out. ive pulled a heap of timing out of current tune whilst i was trying to fix issues. cheers for any advice and critiques. in current tune ive got it set to maf only or primarily as i was trouble shooting. its the same when i have it scaled correctly to run off the vve in the lower revs

currently logging spark torque management type but its showing me none

this is just an idle up and down road whilst im trying to figure out issues

Short answer is your min final airflow is too high.

When you coast down, the ECM is looking at table 12104 to determine what RPMs it should idle at.
Then it uses the coastdown over/under spark table to attempt to hit that RPM.
Once it hits the Min Final Spark it is then forced to use airflow to control idle.
It removes air until it bottoms out at the Min Final Air.

Your Min Final Spark table (12701) is...interesting. I would suggest returning it to stock.
Return your Percent Max tables (2177 and 2178) back to stock.
Adding some more RPM to the coast down RPM table (12104) to make it less aggressive in cutting RPM in the coast down RPM range
Remove air from the Min Final Airflow table (12087) for gears 2-6 in the coast down RPM range

[ineptmath]

Will do first thing in the morning , I was going through the tune u provided me earlier and wanted to thank you for smoothing tables and fixing tables for me I’m going to go through and do one at a time then report back.

(I did flash it and try it)Basically I looked at it saw no difference now a week or two later and 500 posts and 100 trail n error changes I just happened to look at it again and saw how much you had actually changed. Cheers journey of learning is going good feeling a lot better about interpreting the information

Half my problem was I never started from stock but I’m learning a lot by fixing stuff I probably wouldn’t of touched

[ineptmath]

as soon as its acceptable to start this loud ass car, I'm going going to start reverting everything that i can off the data u provided me in the earlier tune and then start tuning it from there.
id love to know the why? as to why its best to do it this way.

if i had to guess (programming experience cross referenced with all the videos and threads I've watched of yours) id say because we are essentially reversing some one else's program and the order of precedence/execution that theyve set?

then secondly because my reference material is basically having 3 tuned cars(whether they are done right or efficiently is another story) to extrapolate data from and see how people have done stuff, WHY have they done it this way? just because that's how they got it to work like that ?

cheers.
another reason i ask is because as me and (computer technician/electrician) father were discussing yesterday after reviewing some tunes that are doing more work via calculating modifiers it seems kind of expensive and a waste of util to have an embedded system using this compute power. (just a discussion haven't deep dived into what the specs of pcm's are)