2004 6.0 NV4500 Tahoe

[Dantheman1540]

I have heard of issues with those coming apart especially under high hp so you might want to check them for wear.

I suppose if it does fail it wouldn't be the more catastrophic thing ever, sure it would make some noise but the axle won't come out from underneath the truck. If they do fail I'm sure we could get a quality heim to replace it.

 

[Dantheman1540]

I started to work on my tune again because there are still a few minor issues that drive me nuts.

They are two symptoms that I think fall under the same issue.

1: When coming to a stop with the trans in neutral or the clutch pressed in sometimes the RPM will climb to about 1,350 when the speedo hits exactly 15mph. By the time the truck comes to a complete stop, the rpm will settle back to the desired level of 675.

2: Same scenario but instead of the RPM climbing it drops straight off and the truck stalls, once again it seems to happen right at 15mph.

I'm getting kinda desperate on this and the HPT forum has been less than helpful so far. I'm kinda to the point of shotgunning stuff and that left me with an aggravating ride on the way home today.

I have repeatedly done the RussK idle tuning method as well as, bump idle spark up, change idle RPM to drastically, and enabled and disabled the MAF (Currently running SD).

 

[randeez]

send the tune broseph

or do i already hab it

think i have it? not sure for what truck of your tho. "dan mod 38 sd....."
not sure how its set up with the manual trans > ie does it always just think youre in P/N? or does it know youre in gear?


first thing i would do is taper off
idle>rpm>rolling
put like 1200 rpm in anything above 30mph and interpolate down to minimum rpm at 0mph

under
idle>airflow>throttle follower> airflow and airflow multiplier
theres a step down right at 1600rpm i would maybe try to add something in there greater than 0. and in the 0 and 400rpm cells bump it way back up like 4-6 so if the rpm does drop that low it'll try and blip the throttle to keep it running


also under idle>airflow>rolling idle> airflow adder
it adds to the idle cracker table, those values seem way too high...and in your cracker table they drop from like 13lb/hr down to 3lb/hr...you prob need to adjust both tables.

 

[Dantheman1540]

send the tune broseph

or do i already hab it

think i have it? not sure for what truck of your tho. "dan mod 38 sd....."
not sure how its set up with the manual trans > ie does it always just think youre in P/N? or does it know youre in gear?


first thing i would do is taper off
idle>rpm>rolling
put like 1200 rpm in anything above 30mph and interpolate down to minimum rpm at 0mph

under
idle>airflow>throttle follower> airflow and airflow multiplier
theres a step down right at 1600rpm i would maybe try to add something in there greater than 0. and in the 0 and 400rpm cells bump it way back up like 4-6 so if the rpm does drop that low it'll try and blip the throttle to keep it running


also under idle>airflow>rolling idle> airflow adder
it adds to the idle cracker table, those values seem way too high...and in your cracker table they drop from like 13lb/hr down to 3lb/hr...you prob need to adjust both tables.

This is the kind of shit I was looking for!

As far as I can tell the truck thinks it's in D4 all the time therefore no tables referring to in PN would apply to anything. I also don't think rolling idle has much or any effect on it because I have increased it to over 3k before with no change noted.

Airflow and airflow multiplier are both tables I don't think I have ever messed with, is there a formula to figure out what you need or a test to run with a histogram? Or is it guess and check?

I noticed on the tune for my RCSB from Atomic the Airflow adder table is totally zeroed out. I copied that but the truck stalled half a dozen times on my way to work after doing that lol. Once again do you have any ideas on a proper way to identify the correct values or is it guess and check?

 

[randeez]

not familiar with the russk idle, but i think its similiar to bigboi (or whatever) method is for gen4 e38 stuff.
is this dbw or cable? cable cause an iac? theres plenty of ways to "make it work" but i like to start at whatever lb/h value it likes to idle at
you basically zero out all the modifier tables, lock timing, and find out the best lb/h at whatever rpm you want and use that as a starting place
if you have the lb/h value hammered out for the desired rpm i would build off of it, meaning 0-400-800 in most of the tables should have that value or something real close to it, it shouldnt need much added via modifier tables so those should be close to zero for now, until you identify instances that need a little bump in idle rpm ie: ac coming on, low speed turning where the power steering pump wants to lug down engine.

have you looked at the stock tune for a 5sp equipped truck to see what they do in those tables?

i wonder if you can log the iac and see what its actually doing

 

[pwtr02ss]

Ahhh, tuning. I have read myself back to not knowing anything in that department

 

[Dantheman1540]

not familiar with the russk idle, but i think its similiar to bigboi (or whatever) method is for gen4 e38 stuff.
is this dbw or cable? theres plenty of ways to "make it work" but i like to start at whatever lb/h value it likes to idle at
you basically zero out all the modifier tables, lock timing, and find out the best lb/h at whatever rpm you want and use that as a starting place
if you have the lb/h value hammered out for the desired rpm i would build off of it, meaning 0-400-800 in most of the tables should have that value or something real close to it, it shouldnt need much added via modifier tables so those should be close to zero for now, until you identify instances that need a little bump in idle rpm ie: ac coming on, low speed turning where the power steering pump wants to lug down engine.

have you looked at the stock tune for a 5sp equipped truck to see what they do in those tables?

DBW and I just sent you a revised tune I'm gonna try OMW home today. Now you have me a little lost on what table you are referring to when telling me what to adjust.

I have referenced my RCSB factory 5speed tune on a lot of this stuff but even the tables I'm fairly certain aren't active have values in them so it's difficult to tell what's useless and what's not. I had considered swapping everything but the VE, spark, and BAF from my other truck into this tune because I think there are some tables missing from this operating system. Plus this current cam was in a 6.0 in that truck and tuned by atomic to near perfection for the short time it was running lol. But I don't want to cheat like that I want to get a better understanding of what does what.

 

[Dantheman1540]

Ahhh, tuning. I have read myself back to not knowing anything in that department

Quit interrupting and stick to transmission knowledge until I have the 4l60 done!

 

[Dantheman1540]

tell you what the HPT forum is so odd, it's like people are scared to post anything publically because they will get ridiculed. I have people PMing me random suggestions not based on facts or data. All worth looking into but I don't like touching things I don't know about.

 

[randeez]

well give the tune a shot and see what it do.

mostly i am just saying when you go thru the russk guide you should establish a stable airflow value at whatever rpm you are targeting. there really isnt any other way to determine that value than trial and error.

one other thing i would try is bumping up the minimum DFCO under: fuel>cutoff/dfco> stall, bump that up to like 1500. it looks like coasting it would drop into dfco mode but you arent compensating for it (tables zero'd out under the idle tab)

dont ever assume tables arent used - some of the calcs dont make a lick of sense for why they do what they do. And even cells within tables that you assume will never get cell hits need to be tuned for the same reason.
the ecu is not perfect 100% of the time, the data it sees isnt 100% accurate and its only as good as what youre telling it to do.

 

[pwtr02ss]

Quit interrupting and stick to transmission knowledge until I have the 4l60 done!

 

[Dantheman1540]

well give the tune a shot and see what it do.

mostly i am just saying when you go thru the russk guide you should establish a stable airflow value at whatever rpm you are targeting. there really isnt any other way to determine that value than trial and error.

one other thing i would try is bumping up the minimum DFCO under: fuel>cutoff/dfco> stall, bump that up to like 1500. it looks like coasting it would drop into dfco mode but you arent compensating for it (tables zero'd out under the idle tab)

dont ever assume tables arent used - some of the calcs dont make a lick of sense for why they do what they do. And even cells within tables that you assume will never get cell hits need to be tuned for the same reason.
the ecu is not perfect 100% of the time, the data it sees isnt 100% accurate and its only as good as what youre telling it to do.

I get what your saying about the idle rpm, It has absolutely no problem idling even down at 675, it's the return to idle it doesn't like and more specifically a long coast while returning to idle. For example; If I compression brake by downshifting as I come up to the stop it is much less likely to stall, if I throw it in neutral at 60mph to coast and brake ride to the stop it's more likely to stall or climb to 1,300 at 15mph.

That DFCO stall makes a lot of sense bumped to 1,500 it is.

I totally understand some tables don't seem to be used but are in some vague way that makes no sense and even HPT them selves probably don't know wtf it does lol. Thats why I try to touch as few tables as possible and only touch stuff I understand which isn't much.

I did find a few other things I fixed such as a enable and disable value being the same which is a no-no as well as not having the spark tables match while making other changes.


Here's a question, what do you suggest idle RPM spart to be at? I have seen a bunch of people suggest raising it significantly like 26-28* to help avoid stalling but then sometimes I hear what appears to be audible knock when I lug the engine from a stop in 3rd gear. Although no kr is ever recorded in my histogram.

 

[Dantheman1540]

Jk bromigo you can post all you want in here

 

[randeez]

i doubt it needs/wants that much timing...but all the same who ever tuned may have put that much base into it and use the multiplier tables to knock it down at idle.
if you just log the idle does it actually see 27* of timing?

 

[Dantheman1540]

i doubt it needs/wants that much timing...but all the same who ever tuned may have put that much base into it and use the multiplier tables to knock it down at idle.
if you just log the idle does it actually see 27* of timing?

I believe it actually shows more like 25.9* not sure what multiplier would be causing that.

Did a couple revisions as I stopped for each errand I did after work. First tune file the one I sent you had the truck stall 5 or 6 times but it did not rev hang or shot up at 1300rp as it did before. I believe this was directly related to the throttle cracker table that I cut a bunch out of so I reverted back to the old TC table and the stalling seemed to go away but the rpm surge came back. So I will try removing 3% or so from the 12-16mph cells and try again tomorrow.

 

[Dantheman1540]

Nothing like nearly bricking your ECU in the Pubdix parking lot. Went in for some chicken wingz and did a tune revision before I left. Of course it fails to write and the starter won't even click over.......

Had to put it in slow write mode and then it took an agonizing 3 or 4 minutes to do its thing but, it worked and I made it home. I did notice a clicking coming from the rear ac junk before I wrote the tune and I think maybe an actuator got stuck and was causing the fail. Scary stuff because despite the fact I had my bench harness I didn't have an extension cord and I was well over 200' from a power outlet.

Things like this make me want a Holley or Haltech stand alone system.

 

[randeez]

small changes....

aand yea a fail to write sucks and usually need to "write entire" to get it to work again which takes a few mins

 

[Dantheman1540]

small changes....

aand yea a fail to write sucks and usually need to "write entire" to get it to work again which takes a few mins

It's hard to force yourself to do small changes moar is betterer after all.

I had a ton of issues with fail to write on this truck but, besides this one today they have been gone since I extended the harness of the chime adapter and I unplug it everytime I write now.

If standalone weren't so damn expensive and didn't require new gauges I'd do it. I'm surprised you haven't yet.

 

[pwtr02ss]

Keep learning sweet cheeks. I'm gonna steal all that hard work via questions. Just ask @iamdub . I did my entire avalanche by stealing all his hard work

 

[Dantheman1540]

Keep learning sweet cheeks. I'm gonna steal all that hard work via questions. Just ask @iamdub . I did my entire avalanche by stealing all his hard work

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