Weird surge with tune

[p66]

I have a friend who has a 1M and a GIAC stage II tune. He recently took the car to the dealer where they reflashed the ECU and wiped the tune. He had the exact same tune reloaded and now it is behaving oddly. While rolling on the throttle smoothly, when the pedal reaches about 7/8 travel, there is a huge surge in power. Almost as if the tune is really dialing up the boost during the over boost phase. This is proving to be very difficult to use on the track. You can imaging rolling on the throttle at corner exit and the power suddenly surging. Very disconcerting. The tune before the dealer reflash did not exhibit this kind of surge. Maybe it did and he just didn't notice, but it would have been because the over boost was much less pronounced. To the point where it was not an issue. GIAC says nothing wrong with the tune. they have made no changes to their tune.

Could this be the result of some new code the dealer downloaded to the DME? He was told the GIAC tune replaces the stock code, so any new code from BMW would be replaced with the GIAC code. Therefore, it should behave exactly the same, regardless what new code was downloaded. Perplexed. Any ideas/suggestions?

[RimasRS]

That was complicated... Let him drive few hundreds for DME to adapt.

[Dackelone]

First you should check for codes in the DME. Does your friend have a way to read the OBDII codes? A bluetooth dongle and a smart phone using "torque" app is a good way to go.

It could even be something as simple as fuel quality or (worn spark plugs) should be changed every ~20K to 25K miles or even a vacuum/boost leak.

All that said, yes BMW for the last few years has been downloading "anti tuner" sw onto our cars when we get a SW update from them. The main purpose is to defeat the tuning programs. Another is to detect and report "tunes" to BMW when ever your car gets hooked up to a BMW dealer's GT1 mainframe pc.

[p66]

The car has been driven about 500 miles and problem still persists. And the problem started immediately after tune was reflashed. When switched to stock mode the surge is almost imperceptible. Just feels like the standard over boost.

I'll advise him to read codes. Thx.

[dEvo6]

Originally Posted by p66

I have a friend who has a 1M and a GIAC stage II tune. He recently took the car to the dealer where they reflashed the ECU and wiped the tune. He had the exact same tune reloaded and now it is behaving oddly. While rolling on the throttle smoothly, when the pedal reaches about 7/8 travel, there is a huge surge in power. Almost as if the tune is really dialing up the boost during the over boost phase. This is proving to be very difficult to use on the track. You can imaging rolling on the throttle at corner exit and the power suddenly surging. Very disconcerting. The tune before the dealer reflash did not exhibit this kind of surge. Maybe it did and he just didn't notice, but it would have been because the over boost was much less pronounced. To the point where it was not an issue. GIAC says nothing wrong with the tune. they have made no changes to their tune.

Could this be the result of some new code the dealer downloaded to the DME? He was told the GIAC tune replaces the stock code, so any new code from BMW would be replaced with the GIAC code. Therefore, it should behave exactly the same, regardless what new code was downloaded. Perplexed. Any ideas/suggestions?

according to what my tuner says, the overboost function is activated only if: 1) M button is pushed 2) WOT (full throttle) from low RPM; it should last 7 seconds, so it quite strange your feeling, expecially if you are not in M mode

[p66]

He is not in M Mode, is in higher rpm range, above 60mph, with smooth pedal application. It's an on/off switch. He's getting plenty of power up to that point so it's not like the boost hasn't kicked in yet. It really feels like the over boost has been jacked up.

[dEvo6]

first of all I would check som logs of boost, but it requires a pressure gauge

[p66]

What would he be looking for with boost logs? Boost psi at various throttle positions/rpms? Would a dyno provide the right kind of data to diagnose the issue?

If it were a vacuum leak, wouldn't he be experiencing a drop in power as opposed to a surge or spike?

[dEvo6]

Originally Posted by p66

Boost psi at various throttle positions/rpms?

exactly. You could also just install a boost gauge and look at it while driving

[robertm]

Originally Posted by dEvo6

according to what my tuner says, the overboost function is activated only if: 1) M button is pushed 2) WOT (full throttle) from low RPM; it should last 7 seconds, so it quite strange your feeling, expecially if you are not in M mode

I'm not sure that's right is it? I haven't hit the M button in over a year and my overboost still kicks in. I think the prerequisites are full throttle and car pointed straight for a certain period of time.

[MDORPHN]

Originally Posted by robertm

I'm not sure that's right is it? I haven't hit the M button in over a year and my overboost still kicks in. I think the prerequisites are full throttle and car pointed straight for a certain period of time.

Quite right, the M button has nothing to do with it.

Neil

[dEvo6]

It sounds strange to me too, I'm just referring what my tuner said to me. He's very reliable and I trust him, my car goes very well after his job and that's all
Here me and one of my friend with M3E92, my car shows more power than M3, obvioulsy more torque (and less brakes I had pads at 0% against his 100 % Pagid)

[E30 Racer]

Not that it explains the OP's problem, but as an FYI GIAC retains overboost even with Stage 2 or 2+. They claim it preserves the "characteristic" power delivery of the 1M. I don't know of any other N54 tuner that does this. Whether you consider this an attribute or undesirable is a matter of personal preference.

[E30 Racer]

BTW, do you know what the latest DME flash is? Still IKMOS?

[p66]

New issue. Driving on highway at about 70 in 6th, punch it, as rpms rise (4,000+) engine starts to shudder. Back out of throttle. No engine light and no limp. Car seems fine. Checked for codes and reader shows b2aaa. Reader has no definition. Anyone know this code? Is it an over boost issue? Would make sense.

[One///Em]

Originally Posted by p66

New issue. Driving on highway at about 70 in 6th, punch it, as rpms rise (4,000+) engine starts to shudder. Back out of throttle. No engine light and no limp. Car seems fine. Checked for codes and reader shows b2aaa. Reader has no definition. Anyone know this code? Is it an over boost issue? Would make sense.

Drop the 'b'. It is '2AAA'

2AAA variable suction unit, plausibility

Here is the full list:
http://www.1addicts.com/forums/showt...highlight=list

[p66]

Sounds ominous. Is that bad? He's at a track event. He doesnt want to bail. Can he ignore it for now?

[One///Em]

Originally Posted by p66

Sounds ominous. Is that bad? He's at a track event. He doesnt want to bail. Can he ignore it for now?

If the engine is shuddering I would definitely not be on a track . Not sure what hardware the code is referencing, but could be VANOS solenoids. Perhaps others can chime in.

[E30 Racer]

Can he use a BT cable to collect a log?

[robertm]

If I were your friend and I was planning on going to COTA today I'd hop over here and ask the same questions. There is a LOT of experience with our motors over there:

http://www.e90post.com/forums/forumdisplay.php?f=58

[p66]

Will check the m3 boards. Thx.

[p66]

Threw caution to the wind. He took it on track and ran his personal best. Fingers crossed he doesn't regret it tomorrow.