[Biturbos4] MTM Boost ISSUE/QUESTION

Michael Benno mbenno at yahoo.com
Wed Dec 3 11:26:51 EST 2003

Some one correct me if I am wrong but limp home mode would be no more than 1bar absolute pressure (the wastegate fully open).
Throttle adaptation is described in the Bentley:

Throttle valve control module -J338-, adaptation

If the Throttle Valve Control Module -J338- or the ECM is removed and installed or replaced, or if the voltage (power) supply to the ECM is interrupted, an adaptation must be performed. 

The learning process (adaptation process) is performed: 

1. Automatically, if the ignition is switched on for at least 6 seconds without operating the starter or depressing the accelerator, and if the Engine Control Module (ECM) registers a "learning requirement." (In this case, however, there is no way of knowing whether the adaptation process was successful or not.) The engine control module will register a learning requirement if the previously stored voltage readings from the angle sensors do not correspond (within a certain tolerance range) to the new voltage readings. (please note this automatic adaptation does not ensure the process was succesful).


2. By selecting "Basic Setting" (function 04), Display Group 060 with the ignition switched on. (use vag-com).

Test conditions for adaptation of throttle valve control module 

No malfunctions stored in DTC memory Page 01-14 , check DTC memory 

Engine not running, ignition switched on 

Accelerator pedal not depressed 

Coolant temperature between 5C and 100C (Display group 004, display field 3) 

Intake air temperature less than 100C 

Voltage supply to engine control module greater than 11 Volts, Checking Page 28-43 

- Connect vehicle diagnostic, testing and information system VAS 5051 or VAG1551 scan tool and select engine electronics control module by entering address word "01" Page 01-8 . Ignition must be switched on.

In Vag Com go to:

-01 Engine (control module)

- 04 Basic Settings

Enter Group 060 and hit Go!

In this condition the throttle valve is pulled into an "emergency running" or default position by a mechanical spring in the throttle valve control module. The values supplied by the two angle sensors for this emergency running position are stored in the Engine Control Module (ECM). The throttle valve is then opened by a predetermined amount. As soon as it reaches this position the current supply to the throttle valve positioner is again disconnected. The spring should then close the throttle valve mechanically to the previously learned default position within a specified period of time (spring test). The throttle valve positioner then closes the throttle valve and the values supplied by the angle sensors in the throttle valve control module are stored in the Engine Control Module (ECM). It is not important how the learning stage counter reacts during adaptation, rather the specification "ADP" is reached after the adaptation in display field 4. The Abbreviation "ADP" stands for


"Witte, Michael J (HPFS)" <michael.witte at hp.com> wrote:
Mike et al,

Thank you for your thorough follow up. The problem became indeed apparent after installation of the chip, stock, I would run easily 6-7psi of boost. Weirdest thing is, as said in my previous email, last night, coming off the highway, I couldn't get the boost over 6psi, whereas right in down-town, on downshifting for a traffic get, and accelerating from that light, I was getting 14psi again. Somebody suggested a limp mode, as limp mode could occur with stock boost as well.

What do you exactly mean by adapting the throttle, e.g. full pressure, or anything to be done through VAG ???

-----Original Message-----
From: Michael Benno [mailto:mbenno at yahoo.com]
Sent: Wednesday, December 03, 2003 10:03 AM
To: Witte, Michael J (HPFS)
Cc: biturbos4 at www.audifans.com
Subject: Re: [Biturbos4] MTM Boost ISSUE/QUESTION

I am not sure I am following you, are you saying that after some amount of driving steady state, the car does not produce full boost?

A couple thoughts come to mind.... If you don't have a leak, then it sound like something to do with the boost pressure control system. You may want to run through the Bently tests (using vag-com). I would say it is something to do with your booster controler (N75) or your bypass controller (remember the ECU can activate the BPV's too they are not soley dependant on IM vacuum). Other possible components that could be problematic are the air temp sensor, and of course the MAF.

One could deduce that bad values from one of these devises could be causing your ECU to artifically limit boost.

I assume your problem became apparent after the MTM chip? It is hard to say if the chip is actually malfunctioning or if is a byproduct of how they have fooled the ECU to procuce higher output, and that your failing component is exlpoiting that modification.

Good luck trying to get anything out of MTM (or Hoppen), I have an irregular shudder on acceleration and all I could get out of them was, buy our spark plugs.

PS, you did adapt your throttle right?

Mike Benno
2000 A6 2.7t 6spd MTM Stage 1

"Witte, Michael J (HPFS)" wrote:

Installed a MTM chip this weekend (on 2000 TIP). 

When oil is warmed up, and boost is requested, I feel, and see (through boost gauge) the improvement, delivering 15psi boost (temps around 30 Fahrenheit outside. Run 20 miles, running on cruise control, switching cruise control off, boost won't get any higher than 6 psi. Detached ECU, reset and read VAG codes, banks lean and rich (indicating bad MAF, I know, its a 2000, MAF will be replaced shortly). Took another test-drive, no problems, on acceleration, easily 15PSI, kick in the back, butt dyno great improvement. On highway, whilst coasting at 70MPH, in fifth, accelerating to 85, again, boost up to 12-14 psi. Dropping speed to 60 mph, accelerating to 100 mph, 15psi. 

Fast forward, trip home, boost all the time, at 15psi, for 20+ miles, at last exit, boost won't come up higher than 6PSI (in any of the gears). Crui sing through downtown, back to 2nd gear, boost runs easily up to 15psi....

Pressure tested, no boost leaks found, BPV's replaced with 710s less than a month ago. Any recommendations, suggestions, or does this chip has a mind of his/her own ?!!?
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