How to reset long-term fuel trim

[paul e]

Yeah, well, as it turns out, there's a tool that costs $480 that can reset the LTFT (autoenginuity, with the

Not bad.. On the autoenginuity web site, for the Enhanced bmw module, it says it gives you the capability of resetting adaption values, among many other functions not available via traditional obdii scantools. This is what it says at http://www.autoenginuity.com/BMW-All-Systems-List.html
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Engine S52-S54-S62 (DME) Active Commands ^
Fuel Injector 1 Fuel Injector 2 Fuel Injector 3
Fuel Injector 4 Fuel Injector 5 Fuel Injector 6
Fuel Injector 7 Fuel Injector 8 Fuel Pump (M5 Only)
Electric Fan 30% Electric Fan 50% Electric Fan 90%
Electrical Box Fan Idle Speed Control 500 RPM Idle Speed Control 1000 RPM
Idle Speed Control 1500 RPM Idle Speed Control Valve 20% Idle Speed Control Valve 40%
Ignition Coil 1 Ignition Coil 2 Ignition Coil 3
Ignition Coil 4 Ignition Coil 5 Ignition Coil 6
Ignition Coil 7 Ignition Coil 8 Oil Circuit ChangeOver Valve Left (M5 Only)
Oil Circuit ChangeOver Valve Right (M5 Only) Oxygen-Sensor Heater, Bank 1, Before Cat. Oxygen-Sensor Heater, Bank 2, After Cat.
Oxygen-Sensor Heater, Bank 2, Before Cat. A/C Compressor Relay Secondary-Air Pump (M5 Only)
Secondary-Air Pump Relay Suction Jet Pump Tank Venting Valve
VANOS Inlet Advance Valve VANOS Inlet Retard Valve VANOS Outlet Advance Valve
VANOS Outlet Retard Valve Reset Adaption Values Transport Mode
Deactivate All


Enhanced BMW Expansion

#EI07 - Access BMW-specific sensors not covered by the OBD-II specification.
Requires new USB or serial hardware Aug. '06+.
$229.95

So, for just $229, we get this enhanced functionality added on to the base autoenginuity module.. Wish my Auterra had this capability. I should have gotten the autenginuity instead I guess, although Im pretty sure I didnt see this reset function available back when I bought mine.. .When I got my auterra, they both worked with the same old palm pilot Im using.. its just that Autoenginuity has enhanced it a whole lot more.. More serious tool it looks like.

[todor]

So I gotta ask more questions about touching the terminals then: wouldn't that reset ALL settings for everything in the car? I know the E36 doesn't have any settings like memorized seat positions or whether or not to use day-time running lights like newer Bimmers, but still, is there anything else that will be impacted by this "reset"? I don't care about the radio, climate control settings, OBC settings, etc. Anything else? I don't wanna screw up something else in an attempt to fix my fuel mixture problems...

['96 E36 M3]

I need to clear my adaptations as well and plan on purchasing the AutoEnginuity tool plus the BMW add-on module. I've already spend $80 in labor to have these values reset once and my local BMW dealer [closer than my usual mechanic] wants to charge me $132 [one labor hour] to do it. It's almost a no-brainer.

[todor]

Just FYI, the adaptations seem to change fairly fast. I ended up not resetting my adaptations and drove the car around for less than an hour after I replaced my MAF and immediately noticed a difference. Just after less than an hour of driving (mostly highway), it had reached the final values where it actually settled. A month later, the values are still the same.

So apparently, resetting the LTFT is not that crucial. You can easily notice them changing in a relatively short amount of time. The only thing you need is an OBD2 tool that can read the LTFT (which is one of the basic OBD2 values).

['96 E36 M3]

Very interesting! I appreciate the feedback...may not need the BMW add-on module after all then.

[todor]

Very interesting! I appreciate the feedback...may not need the BMW add-on module after all then.

Yup. Well actually if you just need a tool to read the LTFT, you don't need Autoenginuity... you can get that functionality on much cheaper tools. The one I use is a homemade version of the ElmScan tool from scantool.net - it cost me $20 in parts, but they also have a pre-made version that's around $50-70 I think. It connects to a laptop and uses Windows software to get all OBD2 readings. Works very well. Obviously, it's not BMW-specific, so don't expect any special features, just the standard OBD2 stuff (which includes showing STFT and LTFT, as well as other cool stuff like whether your fuel injection system is running in open loop or closed loop, the exact voltages that the the O2 sensors are reading, the coolant temperature, intake air temperature, etc.).

[M52 POWER!]

Isn't it stored in EEPROM? In other words it doesn't need electricity to remember it. Kinda like SD cards in many digital cameras.

[todor]

Isn't it stored in EEPROM? In other words it doesn't need electricity to remember it. Kinda like SD cards in many digital cameras.

yeah i thought that too. but i think people are saying that if you short-circuit it, it somehow messes up that stored value. dunno whether to believe that - i haven't tried it myself.

['96 E36 M3]

Yup. Well actually if you just need a tool to read the LTFT, you don't need Autoenginuity... you can get that functionality on much cheaper tools. The one I use is a homemade version of the ElmScan tool from scantool.net - it cost me $20 in parts, but they also have a pre-made version that's around $50-70 I think. It connects to a laptop and uses Windows software to get all OBD2 readings. Works very well. Obviously, it's not BMW-specific, so don't expect any special features, just the standard OBD2 stuff (which includes showing STFT and LTFT, as well as other cool stuff like whether your fuel injection system is running in open loop or closed loop, the exact voltages that the the O2 sensors are reading, the coolant temperature, intake air temperature, etc.).

Interesting. Don't you need to pay for the softare, or is it open source? $70 beats $250 for sure.

[todor]

Interesting. Don't you need to pay for the softare, or is it open source? $70 beats $250 for sure.

The software comes with the hardware when you buy it. And also, they have a free version of the software (which is what I use) which doesn't have features like data logging, etc, but still has access to the basic OBD2 values in real time. There are also numerous third-party free software applications that are compatible with the Elm chip (it's one of the most common OBD2 communication chips).

['96 E36 M3]

Very good - thanks for the information!

[E36LUVA]

Just a quick answer to your previuos question about touching the cables together. What that does is what they call in the VW world, a Capacitive Discharge. Its the answer to most of the VW software glitches believe it or not. It discharges the capacitors in all the control modules in the car and it works and is safe.

[mpathic]

Its a long time later than the first postings, for those who are still at it whacking around the OBDII, the 'safer' way to reset the OBDII ECU is to turn on the double flashers and depress the lighter into it's socket before disconnecting the battery. That will drain the residual charge from the car's electrical system more safely than a sudden cold short across the terminals. My '97 is flipping "not ready" faults while I'm trying to pass CA smog. The tailpipe emissions are fine, its these damn Not Ready warnings that are messing me up.
hth, Barry

Yes its safe to touch them together.

[cybersid13]

Having the same problem with my supercharged stage 2 m3, from AA, they want we to reset the LTFT, so we can do final tune on the car. So, I just touched the two together, it reset everything except the LTFT, I will probably get the Autoenginuity software....

Thanks,

Sean

[328iJunkie]

INPA/DIS does this.

[stevewav]

Free version of LTFT reset : Start the engine, disconnect the MAF sensor for 20 sec (the engine will have a little shock), reconnect the plug and you're done.
I tested it on my car 330Ci 2002 M54 while monitoring the LTFT with my Torque scan connected all the time. In the beginning it was showing -8,5 and after 20 sec went back to 0.

[Header]

yes that also works on my 2003 325i m54

[Coolwater357]

Glad it worked for you but I had no results on 4.8 2006 X5 :-(