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.