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MAJJ
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A year ago, Jan 2019, I had the exact same issue (tunes have expiry dates LOL??). Here to ask what you guys think about this. My tuner is informed. (I'm on Full bolt ons, Gas is 95RON)

Long story short: Tuner believes problem isn't in the tune, because the car is pulling timing more, even though his tune is lowering timing (something like that). He believes it's something mechanical, or the GAS i filled was extra crappy and causing this.
(dont bash he's a VERY reputable tuner locally in the middle east)

Detailed version:
A year later 2 days ago, out of nowhere, boost gauge starting flashing again, and on my AccessPort, Dynamic ADV ranges from -1 to -5. No boost cuts, No CEL, No limp safety codes... apart from the boost gauge car is runs fine.

Did a datalog, sent it to my tuner to check (that's when he replied with the Long Story Short above). He then sent me an updated map pulling more timing i think.. i dont know details about tuning so might be saying it wrong. Anyways. Took the car out to run a datalog and share with tuner just for ease of mind.

Full tank, went on manual and floored it..no flashing nothing.

Today, had an hour drive, and ran perfectly fine no flashing. On my way back, gas tank almost 65%, when i started noticing the gauge is flashing again. so took my time to try to figure out WHEN it flashes. Below are the scenarios (Also Video showing exactly).

1) MOST COMMON: Driving on AUTO, slow acceleration, once I hit 6th and my foot is still on the pedal..gauge flashes with Dynamic adv -4 , -5

2) On Auto, slowly accelerating from 4th .. Flashes

3) SOMETIMES: On Manual, accelerating from 3rd to 4th gauge flashes Dynamic ADV -2, -3

Seems like that knock or gauge flashing issue is somewhere between 4th - 6th gear.

I'm attaching 3 Datalogs if anyone wants to see and help figure out what's causing this. (Still waiting to hear back on my tuner)
Datalog 11 - After noticing the first gauge flash
Datalog 12 - After updated map from tuner
Datalog 13 - Auto, slow rolling 1-6th with gauge flashing on 6th.

Thanks guys, here's the video version.
 

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MAJJ
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Reserved for Updates: sorry if I respond late. Traveling till Saturday night.

NOTE: if it's just bad gas .. currently have 50%. Should I wait till 0 and refuel from guranteed station? or can i just fill over mine now?
 

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I know a guy that runs a performance shop in Middle East , he told me that gas out there is pretty bad quality , he cleans injectors once a year in his performance cars . You most likely got a bad tank of gas or your injectors are clogged up from all the crappy gas
 

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MAJJ
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Discussion Starter · #4 ·
I know a guy that runs a performance shop in Middle East , he told me that gas out there is pretty bad quality , he cleans injectors once a year in his performance cars . You most likely got a bad tank of gas or your injectors are clogged up from all the crappy gas
Yeah sometimes regular stations get a bad batch , so im hoping that's my issue.

From now on ill just fill up from the good ones.

Sent from my iPhone using Tapatalk
 

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MAJJ
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Discussion Starter · #5 ·
I know a guy that runs a performance shop in Middle East , he told me that gas out there is pretty bad quality , he cleans injectors once a year in his performance cars . You most likely got a bad tank of gas or your injectors are clogged up from all the crappy gas
Yeah sometimes regular stations get a bad batch , so im hoping that's my issue.

From now on ill just fill up from the good ones.

Sent from my iPhone using Tapatalk
 

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I'm sort of in a rush so I'll take a more detailed look later, but opening log 12 I see a few things.

  • You can tell when you have a gear change based on the RPM drop/IDC Drop/Ignition timing drop, but you have all these drops and the log is saying it did not change gears so essentially the gear selection being reported seems significantly delayed. Don't think I have seen that before, but doubt it is the cause of your issue.
  • If I put aside the the gear selection in the log and just assume (confident its jacked) its wrong and not playing into the issue, it is knocking right after it changes gear because the timing curve has a noticeable spike and it then causes the knock so tune related and not gas/mechanical related. Essentially, your are at 11deg at 6800rpm and then you switch gears, car goes to lower RPM and torque increases, timing goes down to 6deg, but has a spike to 9deg and the car knocks as you would think it would when timing is jacked. About a 1 minute fix for the tuner.
  • Intake cam timing sucks so holding 20deg at 7K RPM at WOT and you are chocking the motor and probably making it more knock prone.
  • AFR is rich at 11:1 so holding back some power being so conservative
  • STFT is 90% so probably need to tighten up trims to +/- 3%

I've attached a pic so you can see what I mean.
 

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I'm sort of in a rush so I'll take a more detailed look later, but opening log 12 I see a few things.

  • You can tell when you have a gear change based on the RPM drop/IDC Drop/Ignition timing drop, but you have all these drops and the log is saying it did not change gears so essentially the gear selection being reported seems significantly delayed. Don't think I have seen that before, but doubt it is the cause of your issue.
  • If I put aside the the gear selection in the log and just assume (confident its jacked) its wrong and not playing into the issue, it is knocking right after it changes gear because the timing curve has a noticeable spike and it then causes the knock so tune related and not gas/mechanical related. Essentially, your are at 11deg at 6800rpm and then you switch gears, car goes to lower RPM and torque increases, timing goes down to 6deg, but has a spike to 9deg and the car knocks as you would think it would when timing is jacked. About a 1 minute fix for the tuner.
  • Intake cam timing sucks so holding 20deg at 7K RPM at WOT and you are chocking the motor and probably making it more knock prone.
  • AFR is rich at 11:1 so holding back some power being so conservative
  • STFT is 90% so probably need to tighten up trims to +/- 3%

I've attached a pic so you can see what I mean.
GREAT ANALYSIS............
 

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So most of the knock seems to take place right after gear change, at least based on Log 12 and Log 13, which are the only ones I viewed. In the case of Log 13 your part throttle accelerating through the gears at ~3psi and when the car switches gears it initially has knock. When you drop to a lower RPM you're likely generating more torque. In both of these logs you have timing spikes like I showed earlier that correlate with the knock. Because I can't see your actual timing map I can't check to see if you have higher values in that cell that would explain the knock. In such a case you just lower the timing and your done.

If the ignition map is good then it has to be something with the TCM tune and how it changes timing for gear shifts. Have you tried loading a OTS TCM tune and seeing if it resolves your issue? I say this because I had issues with LC5 on my 09 doing something similar when launching so I had to use LC4 and it resolve my issue.
 

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MAJJ
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Discussion Starter · #10 ·
so what you guys are seeing is that theres a TUNE issue causing this .. and ruling out the possibility of bad gas?
 

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so what you guys are seeing is that theres a TUNE issue causing this .. and ruling out the possibility of bad gas?
You have timing spikes that correlate with knock. Looks to be tune related, but cant rule out TCM map since it happens in shift. Ill try to look at the last log later today.
 

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MAJJ
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Discussion Starter · #13 ·
You have timing spikes that correlate with knock. Looks to be tune related, but cant rule out TCM map since it happens in shift. Ill try to look at the last log later today.
so the accessport I have is the V3-005 which doesn't have the TCM control feature.. or is that something the tuner can adjust.

btw, gas tank is now below 50% around 30% and have been driving it daily and suddenly the flashing is gone.. and dynamic adv is only -1 vs before up to -5.
 

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so the accessport I have is the V3-005 which doesn't have the TCM control feature.. or is that something the tuner can adjust.

btw, gas tank is now below 50% around 30% and have been driving it daily and suddenly the flashing is gone.. and dynamic adv is only -1 vs before up to -5.
If you don't have TCM then you are on stock TCM tune. I would advise to add TCM if you can get this resolved through ECM tuning. I'll take a look at the final log today since I was slammed yesterday. Bottom line is there are ignition timing spikes that correlate to knock, at least on the 2 logs I reviewed and you can clearly see on the picture I provided. I will post a picture of the one log I have yet to review to try and explain the knock.
 

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Ok, same story with Log 11. Timing spikes after gear change have direct correlation to knock. I am stil confused why the gear selection logged is lagging the actual gear change. I can see where timing drops to Zero, IDC drops, rpm drops so I know it is a gear change, but gear selection indicator is lagging. Is the TCM causing funky timing values...I don't know. What I do know is you have timing spikes generated by the ECU/TCM causing knock so knock a mechanical issue.
 

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MAJJ
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Discussion Starter · #16 ·
240z thank you so much for the analysis. appreciate the support. It's weird, that the tuner has not noticed this.. he is a very reputable tuner from Bahrain (Kanoo) works on most of the crazy HP GTRS in the region. So is the timing spikes entirely related to the tuner? I ask because I've had this updated map (datalog 11) for 1 year with no issues... until a couple of days ago. Logically, if this was a tuner error it would have appeared earlier ..right?

That's why the tuner suggested it could be just a batch of bad gas filled.. could gas mess up the timing or any other natural causes? I'm almost out of gas now. I'll fill up at a good station today, do pulls and a datalog. I'll share them here again.

Appreciate the help so much.
 

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240z thank you so much for the analysis. appreciate the support. It's weird, that the tuner has not noticed this.. he is a very reputable tuner from Bahrain (Kanoo) works on most of the crazy HP GTRS in the region. So is the timing spikes entirely related to the tuner? I ask because I've had this updated map (datalog 11) for 1 year with no issues... until a couple of days ago. Logically, if this was a tuner error it would have appeared earlier ..right?

That's why the tuner suggested it could be just a batch of bad gas filled.. could gas mess up the timing or any other natural causes? I'm almost out of gas now. I'll fill up at a good station today, do pulls and a datalog. I'll share them here again.

Appreciate the help so much.
I can only see what ignition timing is being commanded since I don't have access to your map. All your tuner needs to do is go to the Ignition table and in the cell that corresponds to the -2DA he needs to check that value to make sure it is not artificially high, which I can only assume it is because of the timing spike. Bad gas or mechanical issues have no way to create timing spikes in your tune.

The way the ignition timing works is there is a table that is RPM vs Theoretical Pulse Width (TPW) so for a given RPM and TPW the ecu commands a specific timing value. I attached one for a DBA that was posted by Sponaugle a few years back so you have a reference. So when you have the initial ignition spike it hits [email protected] TPW. Therefore, your tuner just goes to the map at 5238rpm and 28.8ms and sees if the table value is 11deg. If it is then he just needs to lower that value, which is obviously not rocket science.

If I use the attached map as a reference and look at the ignition timing value at 5200rpm and 28ms it is 11deg :eek:. The tune just appears to be on the edge of what it can handle consistently due to octane issues and it likely has unnecessary timing spikes that need to be smoothed out in the ignition table, but that is my guess.
 

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MAJJ
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Discussion Starter · #18 ·
UPDATE AFTER REFUELING FULL, WITH GOOD QUALITY GAS

After refueling, I no longer have the gauge flashing as before as well as timing pull (dynamic adv) is -1 (vs previously reaching -5). I did two datalogs on 2 Maps.

First, I did a datalog with the recently updated MAP I received from the tuner after informing him about the gauge flash:

  • Datalog 1 (attached)
  • 1-4th pull (R C OFF)
  • No gauge flashing

Second, I decided to switch back to my previous Original MAP, and test that out. With the updated map, the tuner did inform me that he will be pulling more timing, thus car might feel less powerful, which i felt after doing "Datalog 1"

  • Datalog 2 (attached)
  • 1-4th pull (R C OFF)
  • No gauge flashing

I would love to keep using the original map "datalog 2" since the car feels more powerful/smoother. Can you please advise which Datalog looks better? Also, if it looks different than the previous uploaded logs (11, 12, 13 with the bad gas)

Thanks a lot!
 

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