TouringBubble

iTrader: (2)

UPDATE: Issue resolved. See post 19.

===============================

I thought I'd make a new thread here to help others that may have the same issue ...

I installed the NLTS mod on my car and also a friend's car ... both are IX MRs with v.15 ROMs. When working on my friends tune, he experienced some rather odd "bucking" after shifts. I looked at the logs and couldn't pinpoint an issue because he often feathered the throttle after the shift and I assume that was the cause. I drove the car and could not recreate the issue.

Well, I experienced the same issue yesterday and am now able to consistently replicate the problem. It occurs on a normal lift shift at mid throttle. The easiest way for me to replicate is to slowly rev to around 4000 or so in 3rd gear, then do a normal shift to 4th and then go to full throttle. The car shudders badly and the revs jump back and forth in 300 - 500 RPM steps.

I agree with my friend in that this issue began after the NLTS mod. There is no knock present during the occurances.

Below, you will find 2 graphs and the referenced logs that show this issue. Any help would be wonderful.

Tephra Mod Settings ... (Not sure if the names are correct but the vales are ... don't have the map in front of me)

Valet RPM - 3000
Valet Map Switch Time - 8000
Knock CEL Required Count - 3
Knock CEL Required Load - 150
Knock CEL Time - 500
NLTS RPM Drop - 650
NLTS TPS Threshold - 95
NLTS Min Speed - 36



LOG 01



LOG 02

KevinD

iTrader: (56)

i've also experienced this on one car i flashed for NLTS. i didn't have time to look at it after he noticed the problem, so we just took the NLTS off again.

bigric09

iTrader: (37)

where is your foot in reference to the clutch ? are you resting on it by chance ? I did notice that if i touch the clutch ever so slightly after going to 100% tps to shift normally the car bucked because of the NLTS, so either make sure that you shift properly or maybe their is something else in the mix. Im using the version 15 rom as well, and i have no issues at all

l2r99gst

iTrader: (2)

If you can reproduce this, then log the clutch switch as well. Tephra gave the variable to log for that. That will be conclusive evidence whether or not the clutch pedal is being slightly touched during the next gear.

If the clutch pedal isn't being touched or the clutch switch isn't being triggered then it is an issue in the the code and tephra will have to take a look. But, I think we definitively have to rule out that the clutch pedal isn't being touched (foot gently resting on clutch, etc). What you are describing can happen if the clutch switch is inadvertently being triggered.


Eric

bigric09

iTrader: (37)

it cant be the code either as im using the exact same rom unless he copy and pasted something wrong in the XML

TouringBubble

iTrader: (2)

I don't think that the clutch is the issue ... if you'll look at the logs you'll see that the IPW doesn't 0 out like it would if the NLTS fuel cut was engaged.

TouringBubble

iTrader: (2)

I'll try to contact Tephra about the clutch switch log info. Thanks.

l2r99gst

iTrader: (2)

The variable is in one of these threads. I would definitely log that to make sure.

I took a quick peak at the first log and there is one entry of a 0 IPW. The IPW wouldn't stay at 0 when hitting the limiter and the speed of logging may not catch enough of it. I think the only real proof will be to log the clutch switch to see if it the NLTS limiter engaging once or a few times because of the clutch switch.

I will look for the thread real quick.


Eric


EDIT: Here is the post with the variable to log for the clutch switch: https://www.evolutionm.net/forums/sh...&postcount=213

TouringBubble

iTrader: (2)

You are right ... there is that single 0 in the first log but not in the second ... I was looking at the 2nd.

I guess my reasoning is this ... if I did have my foot on the clutch for just a moment after passing the NLTS TPS threshold, how would it be any different than the last moment of an actual NLS? Even if my foot was on the clutch for a brief moment, as soon as it's off the IPW kicks back in and everything is normal. If the RPMs don't jump on a NLS, they shouldn't jump if you bump the clutch during WOT at any other time ...

Mellon Racing

iTrader: (38)

are you sure this isn't bucking due to the motormounts?

tkklemann

iTrader: (6)

Have you adjusted your clutch pedal at all? Reason being is I did mine, then ran into this problem. I suppose even if you didn't, this is still possible. I noticed that when adjusting the pedal height of my pedal, the top clutch switch is just barely touching the pedal itself. It is soo sensitive now that if I look at it wrong it activates NLTS. I have even gotten my pant leg caught on the pedal during a pull and had it disengage...

You might want to poke your head under your dash and see how close/far apart the switch is from touching the pedal. Mine initially from the factory was set so if you tapped it, it would trigger. I am going to adjust it so that it will engage when the pedal moved about 1/4". There is enough play in my switch to do so...

TouringBubble

iTrader: (2)

I'm pretty sure. I've got a poly front mount, but the other car mentioned is on stock mounts. The issue was never experienced before the mod.

I have not adjusted the pedal at all. The car has the stock clutch and about 13.5k miles on it.

I will physically check the switch and also log it on the way home to see if it in fact the issue. I also plan to purposely tap and release the clutch at WOT to see if it causes a similar issue.

dudical26

iTrader: (17)

I have experienced this on occasion. v15 , stock motor mounts.

I have tried to log the clutch flag but I have had some trouble. I have not been able to replicate it often but I will try to see if I can get a log of it. Maybe we can get Tephra in here to check out it and maybe review his code for the v15.

TouringBubble

iTrader: (2)

Update ...

The issue does seem to be clutch related. It may also be related to the motor mounts as well. Here are the graphs ...



In this graph, I purposely held my foot on the clutch enough to engage the NLTS. As you can see, the IPW obviously bottoms out and comes back and the RPM oscillation begins when the injectors come back in. The dynamic of the RPM fluctuation could be related to the motor rocking back and forth as Mellon suggested ...

BUT, wouldn't the same issue happen w/o the NLTS causing the injectors to cut out if it were related to the motor mounts? Yeah, the injectors instantly coming back in will make a slight difference, but the turbo isn't spooled and the motor isn't instantly having 100% load transferred to it at once from nothing in either circumstance.

Here is the second test ...



In this test I simply tapped the clutch just enough to cut the injectors with still at WOT in 3rd. These results do seem to support the motor mount issue. But, is the motor really physically moving enough to cause a 700 RPM spike? That just seems very drastic ...

Thoughts?

tephra

iTrader: (6)

if you can log the clutch switch that would be good, its in the original "no lift to shift" thread... im justin heading in to work so if eric doesn't post it I will find and post...

edit:
https://www.evolutionm.net/forums/sh...&postcount=213

edit2: maybe its a boost problem - maybe the ECU gets confused about the current boost?