Data Logs! Post them here.

[steve99]

Originally Posted by Bergen23

Here's my latest log. Logged KC Learned. What is the Knock Correction Max A Table?

http://www.datazap.me/u/colekmiecik/...log=0&data=1-5

Edit: The OpenFlash guys still haven't gotten back to me about the logging issues after they asked me to update to the latest software and I told them I did that already. Honestly thinking of just ditching the OFT and running the factory tune.

Usuallythe USA/Canada roms are well supported seems a bit weird you logging is not working

Theoretically all D00D rom users should have same problem if your on latest OFT update

Assume your on OFM 1.18
Template SLT6
and let OFT update.
http://openflashtablet.com/Automotiv...ads/index.html

The OFT tunes work well on USA/Canada fuels is only us outlanders that need to tweak for knock on our crappy fuels.

Looking at your KC Learned everything looks fine appears to be running full values as per the Knock Correction MAX A table in your ROM
That table is under Ignition Timing - Advance Folder in romraider

If IAM=1 and no FLKC then the logged values of KC Learned will match the numbers in the Knock Correction Max A table for each RPM/LOAD point

KC Learned = (values in "Knock Advance Max A table" * IAM ) + FLKC(usually negitive)

did a bit of a writeup here
http://www.ft86club.com/forums/showthread.php?t=61820

Your fuel trims look fine
FBKC seems to be logging correctly
derived IAM =1
no evidence of FLKC in KC Learned values

[JB86'd]

Originally Posted by Koa

True true true.. Forgot to ask if you've backed off and added some richness.. were you knocking from tip in or actual advance/preignition or both?

You can see my ignition advance table on the previous page of this thread. That's all of the adjustment I've made. I had tip in knock and knock at high rpm/high load.

[alpax]

Originally Posted by Kodename47

It's more than likely that the tune is designed to run rich and then let the LTFT bring it in line. Don't forget that the LTFT isn't set across the board, but in MAF g/s regions, which is why the LTFTs vary so much in the log. If the LTFTs were all negative below -10% then I'd start looking for issues.

Well, apparently there are issues. I got a bunch of fault codes today: P0172, P117B, P1170.

I believe DTC were triggered when LTFT dropped to -29. I had Torque running on my phone at that moment, so got some logs, not complete, but they show that moment (at 19:01:36):
http://datazap.me/u/alpax/brz-jrsc20...g=0&data=6-8-9

Here's the new log, which I got with EcuTek:
http://datazap.me/u/alpax/brz-jrsc20...&data=3-5-6-11
LTFT definitely drifted further to negative values compared to yesterday (the older log is there as well under "Change Log" button).

[Kodename47]

Originally Posted by alpax

Well, apparently there are issues. I got a bunch of fault codes today: P0172, P117B, P1170.

I believe DTC were triggered when LTFT dropped to -29. I had Torque running on my phone at that moment, so got some logs, not complete, but they show that moment (at 19:01:36):
http://datazap.me/u/alpax/brz-jrsc20...g=0&data=6-8-9

Here's the new log, which I got with EcuTek:
http://datazap.me/u/alpax/brz-jrsc20...&data=3-5-6-11
LTFT definitely drifted further to negative values compared to yesterday (the older log is there as well under "Change Log" button).

I can't fathom what's going on, both logs show differently. It should be that the STFT settle around 0 as the LTFT settle where they want. However looking at your bottom log, if you sum the LTFT and STFT they are around -10, which is what you had before, however the LTFT is massively negative and the STFT seem very positive. It doesn't give much of a clue as to why the LTFT is dropping so low when the STFT is trying to add fuel back in again, it seems strange that the trims are fighting each other. The Torque app does show that it is pulling fuel at a daft rate.

I would preliminary be looking for exhaust leaks or maybe the O2 sensor is faulty. Have you changed any of the exhaust? If not, could it be that the front cat has gone?

[alpax]

Originally Posted by Kodename47

I can't fathom what's going on, both logs show differently. It should be that the STFT settle around 0 as the LTFT settle where they want. However looking at your bottom log, if you sum the LTFT and STFT they are around -10, which is what you had before, however the LTFT is massively negative and the STFT seem very positive. It doesn't give much of a clue as to why the LTFT is dropping so low when the STFT is trying to add fuel back in again, it seems strange that the trims are fighting each other. The Torque app does show that it is pulling fuel at a daft rate.

Yes, I noticed that STFT and LTFT try to eliminate each other. My guess is the tune is supposed to keep the trims around 0, like on the stock car, which makes sense, so when one value moves away from 0, another is trying to compensate.
Here's another log, which I took right after I cleared the fault codes last time. The trim values were almost normal - around 0. LTFT tended to go negative, but stayed above -5%:
http://datazap.me/u/alpax/brz-jrsc20...g=2&data=1-2-3

LTFT stayed around -5 for a couple days, but when I checked two more days later, it was already below -10.

Originally Posted by Kodename47

I would preliminary be looking for exhaust leaks or maybe the O2 sensor is faulty. Have you changed any of the exhaust? If not, could it be that the front cat has gone?

No, the exhaust is stock. Well, everything is stock except that it's supercharged. I'm using the CARB tune, which was designed to work with the stock MAF, fuel and exhaust system.

[Kodename47]

Originally Posted by alpax

Yes, I noticed that STFT and LTFT try to eliminate each other. My guess is the tune is supposed to keep the trims around 0, like on the stock car, which makes sense, so when one value moves away from 0, another is trying to compensate.
Here's another log, which I took right after I cleared the fault codes last time. The trim values were almost normal - around 0. LTFT tended to go negative, but stayed above -5%:
http://datazap.me/u/alpax/brz-jrsc20...g=2&data=1-2-3

LTFT stayed around -5 for a couple days, but when I checked two more days later, it was already below -10.


No, the exhaust is stock. Well, everything is stock except that it's supercharged. I'm using the CARB tune, which was designed to work with the stock MAF, fuel and exhaust system.

The trims don't work against each other, STFTs set LTFT. So consistent negative STFT will make the LTFT go negative. What is meant to happen is that when the LTFT settles the STFT should be around 0 as STFTs are applied to the existing LTFT. There is nothing that tries to make trims 0 overall. The LTFTs will change over time and if your STFTs continue to be negative, then the LTFTs will continue to go further negative. However if your LTFT is negative and then STFTs go positive, the LTFT should start moving back towards 0. This is done for fuel/altitude/temperature changes etc.

Something is causing you to run rich, or think that the engine is. So I'd look at swapping the O2 with a known good one, however I'm sure there have been instances of the stock manifold cat disintegrating causing similar symptoms.

[Bergen23]

@steve99 cheers man!

[Bergen23]

Originally Posted by steve99

Usuallythe USA/Canada roms are well supported seems a bit weird you logging is not working

Theoretically all D00D rom users should have same problem if your on latest OFT update

Assume your on OFM 1.18
Template SLT6
and let OFT update.
http://openflashtablet.com/Automotiv...ads/index.html

The OFT tunes work well on USA/Canada fuels is only us outlanders that need to tweak for knock on our crappy fuels.

Looking at your KC Learned everything looks fine appears to be running full values as per the Knock Correction MAX A table in your ROM
That table is under Ignition Timing - Advance Folder in romraider

If IAM=1 and no FLKC then the logged values of KC Learned will match the numbers in the Knock Correction Max A table for each RPM/LOAD point

KC Learned = (values in "Knock Advance Max A table" * IAM ) + FLKC(usually negitive)

did a bit of a writeup here
http://www.ft86club.com/forums/showthread.php?t=61820

Your fuel trims look fine
FBKC seems to be logging correctly
derived IAM =1
no evidence of FLKC in KC Learned values

I have the latest updates for everything, maybe they haven't gotten around to updating D00D? ( @Shiv@Openflash can you chime in here?)

I've skimmed through that write up you did before. I'll actually read more into it tonight or tomorrow after work. Thank you once again!

[Phantobe]

Originally Posted by JB86'd

You can see my ignition advance table on the previous page of this thread. That's all of the adjustment I've made. I had tip in knock and knock at high rpm/high load.

I switched to Shell.

I had to pull timing in the 2-5k RPM range, I think because I've been running a bit leaner than normal I kept getting knock at low engine loads. .50-.70 is where I was seeing a lot of knock.

Anyways its been running good, my fuel trims are actually more stable then they were on Chevron. LTFT pretty stays below +/-5%. Lowest my IAM has gone is .98, I'll have to make another revision.

[Koa]

Originally Posted by Phantobe

I switched to Shell.

I had to pull timing in the 2-5k RPM range, I think because I've been running a bit leaner than normal I kept getting knock at low engine loads. .50-.70 is where I was seeing a lot of knock.

Anyways its been running good, my fuel trims are actually more stable then they were on Chevron. LTFT pretty stays below +/-5%. Lowest my IAM has gone is .98, I'll have to make another revision.

After being a nearly Chevron exclusive customer for nearly 3-4 years (they opened a station on the Tulalip Reservation where I live.. VERY convienient) I will say Shell petrol 92oct kicks the PANTS off of Chevron's. I don't know if it's a regional thing, but others seem to like Shell better than Chevron for performance. Chevron knocked a bit more for me, consistently. This is over a span of 4 months trying to tune my 86.

[Phantobe]

Originally Posted by Koa

After being a nearly Chevron exclusive customer for nearly 3-4 years (they opened a station on the Tulalip Reservation where I live.. VERY convienient) I will say Shell petrol 92oct kicks the PANTS off of Chevron's. I don't know if it's a regional thing, but others seem to like Shell better than Chevron for performance. Chevron knocked a bit more for me, consistently. This is over a span of 4 months trying to tune my 86.

Really? Oddly enough I've read the opposite, most people prefer Chevron to Shell. At least for 91 octane.

[Koa]

Originally Posted by Phantobe

Really? Oddly enough I've read the opposite, most people prefer Chevron to Shell. At least for 91 octane.

it's blowing my mind and I'm trying to nail it down.. because I don't particularly like filling up with Shell.

The reservation has a deal with Chevron that enables their gas to be at least .50 cents cheaper per gallon. My tribal friends pay no tax... read: $1.40 per gallon right now or less.

[alpax]

Originally Posted by Kodename47

The trims don't work against each other, STFTs set LTFT. So consistent negative STFT will make the LTFT go negative. What is meant to happen is that when the LTFT settles the STFT should be around 0 as STFTs are applied to the existing LTFT. There is nothing that tries to make trims 0 overall. The LTFTs will change over time and if your STFTs continue to be negative, then the LTFTs will continue to go further negative. However if your LTFT is negative and then STFTs go positive, the LTFT should start moving back towards 0. This is done for fuel/altitude/temperature changes etc.

Yes, I understand in general how it works. I meant that in normal conditions LTFT should stay around 0. When LTFT goes further negative, it by design causes larger corrections to the fuel delivery to make it less rich. It looks like the short-term algorithm detects that as a wrong behavior (not enough fuel), because in normal conditions this should not happen, so STFT goes positive to compensate that. Normally it should cause the LTFT over time return back to the correct value of 0. In my case this doesn't happen apparently because of some additional factor, which should not be there.

Originally Posted by Kodename47

Something is causing you to run rich, or think that the engine is.

Exactly! This is my conclusion.

Originally Posted by Kodename47

So I'd look at swapping the O2 with a known good one, however I'm sure there have been instances of the stock manifold cat disintegrating causing similar symptoms.

Before getting to that expensive stuff like O2, MAF and cats replacement, I will start with thorough check for leaks. The intake part seems to be fine - I haven't found leaks around or after MAF. Next on my list are the PCV hoses and connections.

[steve99]

Originally Posted by alpax

Yes, I understand in general how it works. I meant that in normal conditions LTFT should stay around 0. When LTFT goes further negative, it by design causes larger corrections to the fuel delivery to make it less rich. It looks like the short-term algorithm detects that as a wrong behavior (not enough fuel), because in normal conditions this should not happen, so STFT goes positive to compensate that. Normally it should cause the LTFT over time return back to the correct value of 0. In my case this doesn't happen apparently because of some additional factor, which should not be there.

Exactly! This is my conclusion.

Before getting to that expensive stuff like O2, MAF and cats replacement, I will start with thorough check for leaks. The intake part seems to be fine - I haven't found leaks around or after MAF. Next on my list are the PCV hoses and connections.

Simplified explanation Open loop/Closed loop fueling

Usually open loop is used on initial start and during warmup, until the 02 sensor reaches its operating temperature and produces a reliable signal , at which point the ECU switches to closed loop for idle. Warmup mode is Fuel System status =1

Under heavy acceleration or abrupt throttle movement the system will generally go open loop. Fuel system status =4

During cruise and idle it will generally be in Closed Loop mode Status = 2

When the engine is running in closed loop, it is using the signal from the O2 sensor to regulate the AFR in conjunction with the MAF sensor. There is a feedback "loop" between the O2 sensor and ECU so the ECU continuously makes adjustments based on the O2 sensor data.

The correction applied by the ECU due to the O2 sensor input will be in the form of STFT, if the STFT stays negative or positive consistently for a period of time in an area it will be written to LTFT. There are five bands of LTFT based on MAF sensor flow rates (roughly related to engine RPM) where the ECU stores the LTFT. This is a continuous learning process and other offsets and compensations are applied due to IAT, Pressure , coolant temp ect.

In open loop the O2 sensor isn't used and the ECU sets fueling based on stored maps(OL fueling AFR target maps) the MAF sensor input and LTFT trims learned when engine was running in Closed loop mode.

So if you MAF scaling is out you will build up large LTFT when on Closed loop mode these will be stored and then applied as corrections when you go Wide open throttle.(Open loop mode).


However if the MAF scaling is out by a considerable amount you will build up large say over 5% LTFT while your cruising around in Closed loop.

Then when you go Wide Open Throttle (or just more aggressive throttle movements) this stored LTFT is applied as a correction to the fuelling targets in Open loop mode and throws off your AFR.

Large differences in Temperature , usually occurs around idle when engine bay heats up will all effect maf and hence fuel trims.



If you log AFR (o2 sensor reading), Commanded AFR (what the ECU is asking for) LTFT, STFT, MAF V ,MAF, throttle position, rpm , IAT LOAD , Fuel System Status , you might get a better idea of what is going on.

If you logging system can monitor the second O2 sensor as well it may be worth comparing the reading from front/rear 02 sensor and see if they are reasnobly consistent.