Quadzilla Shudder light throttle

[kzimmer]

54 minutes ago, Me78569 said:

It ia fair to say that this only happens when boost = 0?  

Alight try this one.  Another change I made before the issue happened was change the map sensor offset from 12 psi to 13 psi to keep the quad from reading hte wrong boost value.  

 

This tune makes it impossible for the quad to see less than 0 psi of boost.  

ADRV2easytime.exe

 

Definitely when boost shows 0 for me. Tried this one. Still does it. 2-4% TPS, 930-980 rpm.

[Me78569]

ok.  

 

 

[Me78569]

@kzimmer 

 

I can reproduce your issue, I know what it is and I can't really do anything about it.  The issue is the ecm and the quad are playing ping pong with fueling.  As rpms come above 950 then the quad steps in and starts to pull fuel because your tune is setup to reduce fueling due to the size of injectors.  that causes the rpms to fall for a split second and the ecm then adds fuel which causes rpms to jump and the cycle repeats.    

 

@kzimmer 
I just looked at the smoothing function I had built and it was only in place when rpms where under 900, so removing it did nothing in this case.  

 

@mopar1973man 's issue happens regardless of tune starting point and is not limited to the 950 rpm range.  His issue is an actual miss rather than rpms bouncing.  still chasing that.  

Edited August 29, 2017 by Me78569

[kzimmer]

5 minutes ago, Me78569 said:

@kzimmer 

 

I can reproduce your issue, I know what it is and I can't really do anything about it.  The issue is the ecm and the quad are playing ping pong with fueling.  As rpms come above 950 then the quad steps in and starts to pull fuel because your tune is setup to reduce fueling due to the size of injectors.  that causes the rpms to fall for a split second and the ecm then adds fuel which causes rpms to jump and the cycle repeats.    

 

 

@mopar1973man 's issue happens regardless of tune starting point and is not limited to the 950 rpm range.  His issue is an actual miss rather than rpms bouncing.  still chasing that.  

 

Interesting. The only thing that bugs me is that i'm almost positive 2.5.1 didn't do this. I'm guessing this has to do with the off-idle handoff changes. Can you add a hysteresis? IE Quad takes over at 950, gives up at 850. Or gives up if TPS < 1%.  I'm a big fan of hystereses in stuff like this, helps make things smooooooth. The possibilities are endless, too bad free time isn't, haha.

 

2.5.4 from the download section is smooth as hell if i skip right to 7% + tps, and I really like it. Let me know if you need me to try anything.

 

-Kole

[Me78569]

I can't rely on TPS input to tell the quad when to fuel since cruise control on late trucks does not report a TPS.  Been down that road and we just add a bunch of issues related to that to solve this issue. 

 

I might be able to trigger it to fuel until rpms fall, but I will have to think through the issues involved with that.

 

the hand off was different on older tunes, but they had their own issues with stalling offidle etc depending on the truck configuration.  This method is MUCH smoother for manual trucks starting.  Damned if I do, damned if I don't

[kzimmer]

3 minutes ago, Me78569 said:

I can't rely on TPS input to tell the quad when to fuel since cruise control on late trucks does not report a TPS.  Been down that road and we just add a bunch of issues related to that to solve this issue. 

 

I might be able to trigger it to fuel until rpms fall, but I will have to think through the issues involved with that.

 

the hand off was different on older tunes, but they had their own issues with stalling offidle etc depending on the truck configuration.  This method is MUCH smoother for manual trucks starting.  Damned if I do, damned if I don't

 

Yeah it would be tough to have a one size fits all base tune to make everyone happy. I would say this is damn close.

 

I also just verified your findings by changing to a different tune, altered canbus fuel. No lope. Good catch.

[Mopar1973Man]

Something about the Quadzilla not following the fueling table or the ECM isn't releasing fully? It's a very random miss and disappears as the TPS and RPM rise. The starting edge of the Quadzilla data is like very dirty or something. 

[Me78569]

@Mopar1973Man

So if you were to take the truck down the road at 1000 revs in high gear then go from low TPS to high TPS would it miss until rpms come above ~1200 or would the miss clear up as soon as you put your foot into it?

[Mopar1973Man]

Yes. Gear doesn't matter nor speed just the light throttle in that RPM range. As soon as you start gaining RPM at light throttle or mash into the throttle the miss is gone.

[Me78569]

So jus tto be %100 clear, if you had the truck setup where you could increase TPS to %100 but not gain speed, the miss would go away as soon as you input higher TPS?  

[Mopar1973Man]

Not that I know of. It based on RPM and light throttle. That's the best I can give you. I know if I drive with heavy foot you don't notice it. Now if you being mellow cruising parking lots then it pop up. Most commonly in small town speed limits down 25 MPH or following tractors on the highway. 

[Dodgeih]

Saving for later to read whole thing. I have very similar issue to what I read on first 2 pages will read the rest later tonight

 

[Me78569]

If you can reproduce the issue please let me know. 

 

It is %100 normal for this shudder in the 950 rpm range, but it should clear by 1000 rpm.  If you get a lope like mike in the 1000-1200 range I need to know.  

[Dodgeih]

2 hours ago, Me78569 said:

If you can reproduce the issue please let me know. 

 

It is %100 normal for this shudder in the 950 rpm range, but it should clear by 1000 rpm.  If you get a lope like mike in the 1000-1200 range I need to know.  

Just read it all.. Thinking mine is more of an annoying big injector/crossover tube lope. I'm going to do a little comparing tomorrow. Things are similar yet different...

Rolling in second 1-2% throttle is a lope, like lb7 stupid lope tune lope... If I come around a corner slow low rpm and kinda load it it bucks and surges. If I'm going through town I have to keep rpm up or it bucks. Idk exact rpm/throttle% it's happening but will look tomorrow. Also seems the lower the can bus starts the worse it gets. I want to start around 70% but that's impossible 75 to 80 it a much more drivable.. Also if I hit 1% (maybe 2 I'll check) throttle at idle or cruising very slow rpms actually drop a touch.. 

 

I'll get specifics tomorrow... 

[Mopar1973Man]

That is something I can try as well. Maybe that is the problem right there the CANBus fueling is not limiting correctly for some reason. I could try building a tune that is well above my current 85% start and see if it goes away. Then build another tune that is cut a bit deeper like 70% and see if it gets worse. 

 

I bet this is the whole problem. 

Edited September 6, 2017 by Mopar1973Man

[kzimmer]

8 hours ago, Dodgeih said:

Just read it all.. Thinking mine is more of an annoying big injector/crossover tube lope. I'm going to do a little comparing tomorrow. Things are similar yet different...

Rolling in second 1-2% throttle is a lope, like lb7 stupid lope tune lope... If I come around a corner slow low rpm and kinda load it it bucks and surges. If I'm going through town I have to keep rpm up or it bucks. Idk exact rpm/throttle% it's happening but will look tomorrow. Also seems the lower the can bus starts the worse it gets. I want to start around 70% but that's impossible 75 to 80 it a much more drivable.. Also if I hit 1% (maybe 2 I'll check) throttle at idle or cruising very slow rpms actually drop a touch.. 

 

I'll get specifics tomorrow... 

 

That's the same problem as me, because of low canbus start. When the quad takes over rpms drop and quad releases control. When quad releases control rpms increase. Repeat.

[Dodgeih]

8 hours ago, Mopar1973Man said:

That is something I can try as well. Maybe that is the problem right there the CANBus fueling is not limiting correctly for some reason. I could try building a tune that is well above my current 85% start and see if it goes away. Then build another tune that is cut a bit deeper like 70% and see if it gets worse. 

 

I bet this is the whole problem. 

Yeah I would try that. I could try lowering can bus and see if I mimic you as well...right now mine is not a miss like yours but maybe that's just a difference in motors.. Mine is more of a bad lope from 950-1050 under light throttle and/or higher load.. Similar to @kzimmer

 

Edit the rpm range of incidence was higher before @Me78569 corrected my goofy boost offset and my can bus was lower. 

Edited September 6, 2017 by Dodgeih

[Dodgeih]

Update. I tried lowering can bus to 50%. It made it worse but the rpm range is the same. 950-1050. I really think my problem is the combination of larger tubes, pretty big injectors and the quad fighting for control. I think mine can be nearly cured by learning how to drive it again! Ha ha! 

 

I am possibly going to adjust a couple of my tunes to lower the start point again.I really like the lack of smoke at 60% and I can ramp up fairly quickly so I still have good passing power

[Me78569]

Yea that lope you fele is the Quad and the ecm fighting for control.  

 

 

[Mopar1973Man]

Ok. I've done some digging. 

 

Default tune doesn't have this problem. It's clean. 

 

More you drop the 0 PSI or 1 PSI fuel timing makes it lopey off idle. 

 

I'm curious of what the timing setting is for the 1,000 to 1,499 bracket since there isn't one. Timing spikes high to 18* roughly in this bracket. My 1,500 position is set for 15* so with low cruise timing add then 18 would sound correct for 1,500 and up. But not correct for 1,000 to 1,499 range.