S4wiki:Community Portal

The Community Portal is the central place to find out what's happening on S4Wiki. Learn what articles need to be written, what questions need to be answered, and what articles still need a lot of work.

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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?

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?

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)

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?

ME7.1

 * sigh. stub for now.


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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: req load-> base maps + EGT enrich + adapt channels + trims? + load (derived from maf)
 * What inputs are used in each to determine boost
 * What inputs are used in each to determine timing
 * 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
 * desired 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 - only accurate near stoichiometric A/F
 * Why get a wideband sensor for tuning?

Knock control

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

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
 * N249 controls BPV


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