S4wiki:Community Portal

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MAF

 * Bosch signal characterization
 * What voltage indicates "zero" flow?
 * What voltage indicates negative flow? Does the ECU use it?
 * Is MAP used in characteristic curve when ECU detects broken/unplugged MAF?
 * Near the top of the MAF range, it seems to have a smaller and smaller effect on fueling. Does this mean that maxing the MAF isn't as bad as many believe?

Lemmiwinks

 * High EGT (>980&deg;C) and IAT (>120&deg;F) corrections..
 * is there a flag for each, or is the correction progressive?
 * does it affect both fueling and timing?
 * does it affect req boost?
 * does it affect load calculations?
 * there is no direct evidence to support there are any "high-IAT" based corrections, only EGT enrichment
 * The load discussion in the lemmi article is pretty much 100% bullshit. hopefully somebody can fix it

Generations

 * There is some confusion with cars near the 09/00 build mark
 * Some are 2001, some are 2001.5 (no verification of this rumor)
 * Some 2001.5 came with h-boxes and do not appear to have F-hoses (doubtful, probably incorrect report)
 * Still trying to figure out what the AGB engine code is

Long term fuel trim/Short term fuel trim

 * These articles were directly stolen from this BMW OBD-II article. They need to be checked for accuracy wrt. the S4 and ME7.1

Glossary

 * huge disaster in general. currently just redirects to list of abbreviations. Should get rid of redirect and make a good one.

Bypass valve

 * need more part number information
 * need to reformat into a table
 * need more revision information (and pressure specs etc)

Cluster recode

 * verify there is only h-box/m-box encoding
 * is there tip/6sp variation?

Engine recode

 * different between ESP/non-ESP, but how does it interact with ABS and EDL?

ME7.1

 * sigh. stub for now.


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ECU Explorer

 * USB driver howto
 * registration key guide

Load (aka Charge?) vs Torque

 * self study refers to the following "torques"
 * 1) external torque requests
 * 2) internal torque requests
 * 3) nominal inner torque (spec torque?)
 * self study refers to the following "charges"
 * 1) actual charge (calc load?)
 * 2) nominal charging moment (spec load?)
 * 3) nominal charge (spec load corrected?)

Open loop/closed loop

 * What determines which is used when?
 * What inputs are used in each to determine fueling
 * closed loop: req load-> base maps + adapt channels + ltfts (derived from stfts) + stfts?
 * stfts derived from narrow band
 * open loop: calc load (from maf) + req load -> base maps + EGT enrich + adapt channels
 * What inputs are used in each to determine boost
 * What inputs are used in each to determine timing
 * calc load (from maf) + req load -> base maps + IAT correction + retard (derived from correction factor)
 * correction factor derived from kvs
 * What inputs are used in each to determine throttle plate angle
 * req load (based on throttle position during partial throttle or target idle torque if throttle postion is zero) vs calculated load (based on MAF)
 * add in cruise control, traction control, engine protection (e.g. throttle cut)

O2 sensor

 * Narrow band sensor - only accurate near stoichiometric A/F. Only good for closed loop.
 * Wideband sensor - accurate everywhere! Great for tuning open loop.

Timing and Knock control

 * Relationship between KVs and timing correction factor
 * Direct?
 * Filtered/corrected somehow?
 * Are logged KV's corrected?
 * Relationship between IATs and timing maps

Characteristic curve

 * When is it consulted?
 * During both open/closed loop?
 * Is MAP used?
 * What if ECU detects broken/unplugged MAP?

Synchronous path/Asynchronous path

 * Synchronous path outputs: VVT, ignition timing, injector pulse width
 * Asychronous path outputs: requested boost, throttle plate angle

F-hose

 * Why does it exist?
 * Delete howto

Master boost controller

 * Parallel vs series vs alone
 * Tuning
 * Relation to throttle cut and TCD

Throttle cut defender

 * aka MAP clamp

N75, N249, Wastegate

 * N75 controls wastegate
 * how is req. boost related to waste gate duty?
 * why delete? (to use MBC, AVCR etc)
 * N249 controls BPV
 * why delete? (no conclusive proof of any advantages)

RNS-E Nav information

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