Advance Mutiplier resetting on restart?

[andrew20195]

Originally Posted by mad_sb

i'm 100% sure this has nothing to do with power connections to the ecu.

This may sound silly, but have you tried logging battery voltage when cranking? If you have a weak battery or a starter that is drawing too much current, it is possible the voltage could drop below 10. Computers do funny things sometimes when exposed to intermittent low voltage.

[feldy]

Originally Posted by andrew20195

This may sound silly, but have you tried logging battery voltage when cranking? If you have a weak battery or a starter that is drawing too much current, it is possible the voltage could drop below 10. Computers do funny things sometimes when exposed to intermittent low voltage.

I did try this today. And it did indeed drop below ten on each crank. Dropped down to 7.56 or something. 8's the other times. @mad_sb you seeing the same thing. Anyone have a good battery sitting around. I guess ours not even two years old is starting to go?

[sw20kosh]

Mine never resets. I have one of the first FR-S's. Hmmm

[Silverpike]

Is it possible this change is due to the ECU changes Toyobaru made due to fix the CEL/SL/Idle problem? Some have the fix and some may not ...

[xjohnx]

Originally Posted by Silverpike

Is it possible this change is due to the ECU changes Toyobaru made due to fix the CEL/SL/Idle problem? Some have the fix and some may not ...

Interesting theory. No fix here (nor am i aware of one for the BRZ's?) and no IAM reset.

[xjohnx]

Things just got weirder. I just confirmed that the source of this issue is almost certainly NOT hardware based.

My BRZ Limited had not been resetting the IAM on restart, however recently (as in today) it started to reset it. I think I may have noticed a pattern that may explain it.

On my car, it seems that if the current IAM is less than the initial IAM of the rom you're running, then it does not reset. (IE - Was running Moto-easts tune, default IAM is .7, when mine was less than .7 it would not reset on restarts.)

When your stored IAM is greater than the default for that rom, it resets at startup. (IE - my IAM was at .74, restarted the car and since the initial IAM on this rom is .7, and .74 is greater than that, it reset to the default for that rom. Perhaps I wasn't seeing this behavior before since I was running another vendors tune who set the IAM to 1 by default, thus making it impossible to reset at restart if my theory is correct.)

Here's a screenshot of a datalog I did showing the IAM pre-startup, the startup sequence, and the IAM post startup:

[sw20kosh]

Originally Posted by xjohnx

Things just got weirder. I just confirmed that the source of this issue is almost certainly NOT hardware based.

My BRZ Limited had not been resetting the IAM on restart, however recently (as in today) it started to reset it. I think I may have noticed a pattern that may explain it.

On my car, it seems that if the current IAM is less than the initial IAM of the rom you're running, then it does not reset. (IE - Was running Moto-easts tune, default IAM is .7, when mine was less than .7 it would not reset on restarts.)

When your stored IAM is greater than the default for that rom, it resets at startup. (IE - my IAM was at .74, restarted the car and since the initial IAM on this rom is .7, and .74 is greater than that, it reset to the default for that rom. Perhaps I wasn't seeing this behavior before since I was running another vendors tune who set the IAM to 1 by default, thus making it impossible to reset at restart if my theory is correct.)

Very interesting except that mine did not do that yesterday...

When I got to work in the morning my IAM was at 0.54. After work I expected the IAM to be 0.54 after I started it up but ALAS it reset.... The IAM was now at 1.0...

I was able to make the IAM drop (to 0.86) by applying a lot of load/boost in the 2k rpm zone (btw no knock correction, just IAM dropping...). Now I know why commuting to work was able to drop my IAM to 0.33.

To make things even more weird, this pattern did not repeat. This morning when I started it up I expected to see the IAM reset to 1.0. Nope. It was still at 0.86...

[xjohnx]

Originally Posted by sw20kosh

Very interesting except that mine did not do that yesterday...

When I got to work in the morning my IAM was at 0.54. After work I expected the IAM to be 0.54 after I started it up but ALAS it reset.... The IAM was now at 1.0...

I was able to make the IAM drop (to 0.86) by applying a lot of load/boost in the 2k rpm zone (btw no knock correction, just IAM dropping...). Now I know why commuting to work was able to drop my IAM to 0.33.

To make things even more weird, this pattern did not repeat. This morning when I started it up I expected to see the IAM reset to 1.0. Nope. It was still at 0.86...

so very weird. i know this isn't likely, but you didn't do a dtc reset last night by any chance did you?

[sw20kosh]

Originally Posted by xjohnx

so very weird. i know this isn't likely, but you didn't do a dtc reset last night by any chance did you?

Negative

[xjohnx]

Originally Posted by sw20kosh

Negative

figured as much.

i wonder if the guys at ECUtek have encountered this yet (just named ecutek because i'm guessing they've spent the most time developing for these ECUs and are likely the most familiar) and found an explanation for it?

[sw20kosh]

Originally Posted by xjohnx

figured as much.

i wonder if the guys at ECUtek have encountered this yet (just named ecutek because i'm guessing they've spent the most time developing for these ECUs and are likely the most familiar) and found an explanation for it?

The reseting seems random to me as it stands which is fustrating.

Also fustrating: my previous ROM was a rock star for months pegged at 0.9ish - 1.0 all the time. Then at 4:30 am on my way to the road course all excited to try out the tune... my IAM drops to 0.28-0.33 cruising there. So now my ecu doesn't like the calibration?

I figure ok maybe it is low rpm stuff that it doesn't like so I add half a can of Torco octane booster (brings it to ~95 octane) and drive it around the road course (high load / high rpm) 7 laps. IAM is still at 0.33 even with the higher octane...

It was time to re-flash the ecu with the same tune and start from a IAM of 1.0. Guess what? 7 or so laps later and it is 0.96. Happy again...

[xjohnx]

Originally Posted by sw20kosh

The reseting seems random to me as it stands which is fustrating.

Also fustrating: my previous ROM was a rock star for months pegged at 0.9ish - 1.0 all the time. Then at 4:30 am on my way to the road course all excited to try out the tune... my IAM drops to 0.28-0.33 cruising there. So now my ecu doesn't like the calibration?

I figure ok maybe it is low rpm stuff that it doesn't like so I add half a can of Torco octane booster (brings it to ~95 octane) and drive it around the road course (high load / high rpm) 7 laps. IAM is still at 0.33 even with the higher octane...

It was time to re-flash the ecu with the same tune and start from a IAM of 1.0. Guess what? 7 or so laps later and it is 0.96. Happy again...

interesting, i was having a bit of the same issue lately.

[regal]

Originally Posted by mad_sb

I thought about that but it is not a power issue. If you key on but don't start the engine the IAM and fine learning will still be there from the previous drive cycle. Once you start the car, it resets to the roms initial IAM value.

I will double check this afternoon when i leave the office.
EDIT: confirmed after sitting for 6 hours or so, keyed on, connected logger, refreshed learning view... same values were there from before I shut off the car at work this AM. Left logger connected, started engine, refreshed learning view, fine learning was reset to all zero's. I am back on E85 now and have initial iam set to 1 in the rom so there was no change to notice in the IAM but since fine learning was present prior to cranking i'm 100% sure this has nothing to do with power connections to the ecu.



Yup, most of us already posted that a couple pages ago..

My working theory on this issue:

It is well documented that it was difficult during development to extract 200 hp out of this engine. In fact dynos of the stock tunes posted everywhere are really not indicative of a typical 200hp engine. I haven't seen any independent engine dynos but I suspect this engine is comparable to what most cars would be factory rated at 180-190 crank hp, I'd bet my last dollar its not a factory 200hp car on cali gas. The engineers probably had a solid 200hp before the emissions band-aides were applied and the chassis got heavier than initial design.

So they made it reset to 0.7 IAM, if you have good gas and don't cruise around in closed loop under load where there is a lot of knock it then IAM will improve, but they don't trust it enough to make it persistent, its sort of a small gimmick so they can call it a 200 hp engine.

I know this doesn't explain the reported cars with a persistent IAM, but I'm not sure those cars were turned off for a length of time or if they were JDM configured that slipped thru the cracks. I haven't a persistent IAM car around here..

Obviously this is speculation on my part but this is the take away:

Get rid of the manifold cat and tune it based on a 0.7 IAM. The key is to tune it such that the IAM is a non-factor just like scaling the map for low correction.

I have always considered a good tune one that doesn't rely on the knock sensor so much except for a rare bad tank

But I hope I'm wrong and its just the small battery dropping voltage during cranking, or maybe the cranking makes the knock sensor sing and we just need to silence it during cranking.

Just don't have the enthusiasm to really dig into it till we have a solid header on the market to really justify investing time and $'s into tuning.

JMHO

[jamesm]

if the initial value is configurable, does it matter that it resets (to 1, perhaps) every time?