startuned magazine february 2012

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February 2012 Edition of Mercedes-Benz StarTuned Magazine.


  • 1. j fSTARTUNEDInformation for the Independent Mercedes-Benz Service Professional February 2012U.S. $6.00 9.00Volume 12Number I ^m% One of the Star Points: Ignition Sealing the DealGood As New on Airlfc- !Mercedes-Benz

2. FIRE.... . . on all eight with USA Dealer Workshop Services is the source for all the technicalinformation needed to support, service, and maintain Mercedes-Benz vehicles.Mercedes-Benz workshops rely on DWS products and services for getting jobsdone quickly and more efficiently. Our products include:STAR Teklnfo with WIS-net (Workshop Maintenance Manuals and SheetsInformation System) STAR Service Manual Library CDsElectrical Troubleshooting ManualsWIS and DAS software updatesInstallation Instructions Star Diagnosis System (SDS)Technical Bulletins Operators Manuals and COMAND ManualsCampaigns Mercedes-Benz EquipmentMercedes-Benz Special Tools Inventory of technical publicationsSTAR TeklnfoDealer Workshop ServicesEngineering Services,Mercedes-BenzMercedes-Benz USA, LLC. 3. i;,!(..-:::. ..:4:-,.:::^.fv; XXX+ fXXX< IN THIS ISSUE WelcometoStapTunedUhe-magazine for independent .servicetecl*n;piapsvvorkingor-MerGede3-3enrvenie)es. Y31V ^;iMsroedes&enzdealejFsponsoPslSbnlTun^ : ; ; : . r : " v ^ r "l":::.:::-:l-V;:.i ::J^ - l ! rJ xinformation coming your way in.each issue.- *t f J , + " * f q-^ LJ* ^ J, *14.*^ 4 ONE OfcliHE STAR POINTS: IGNITIONMercedes-Benz wants to present the information you-need to ,111Our-digest of.|help;yojjsdlve -v 5 "unanticioated prcplems quickly and expert*.: ;fiieaseletiiS^nowiist-whaiskindsw features md;other diagnostic: seiwides^dufdl like.foiseeijniifcfotefteontlnueitb-; , : *-:. - :- it! ilrt..:., -;: ;L.. ::LWM * -, ? :; ,: .: t...jf3 i : ~ , "%wtipropertyymfy i S$$^- gmyrmngemqyims three elements tow$rkix^getherin perfect harmony: compression, :J {S,*:; fuel, and, our subjecthere, spark. Maintainingthis harmony insures the legendary powerand performance ofMercedes-Benz vehicles. 5. ~ln any team sport, players need to work together dedicated ignition module controls the ground sideto achieve a goal. The same applies to theof the coil. When the coil is grounded, a magneticinternal combustion engine. The basic engine is field is created in and around the primary windings.engineered to take in and compress quantities ofThe secondary windings contain many more wrapsair. The fuel system combines a flammable liquidof fine wire than the primary does. When thehydrocarbon with this air at the optimal ratio to module or computer "un-grounds" the coil, theprovide a clean-burning mixture. In a diesel engine,circuit is broken and the magnetic field collapsesignition occurs naturally, so when that happens isinto the secondary windings, and the result isdetermined by the timing of the injection event. In high voltage. The ignition systems found on oldera gasoline engine, on the other hand, the mixture vehicles before the mid-90s had coils with singleis compressed to a point where it is ready to secondary towers. The spark out of this tower wouldburn, then the ignition system provides the high- be sent to a distributor cap and rotor, which wouldvoltage, low-amperage spark that ignites it. If then distribute the spark to each cylinder in its turnthis spark were to occur at the wrong time in the timed to coincide with its piston approaching TDCengines cycle, harmful emissions would increase, (Top Dead Center).fuel mileage would fall, and performance wouldbe reduced. Internal engine damage is anotherpossibility. In the old days, we were able to adjustHow We Get kV from Just Vspark timing by twisting the distributor, or changing-The induction phenomenon that generates manythe gap of the ignition points. Now, of course, the tens of thousands of volts at the spark plug gapcomputer provides vastly more precise adjustments from mere battery voltage is both interesting andthroughout the rpm range. subtle, but its not our purpose here to providea detailed physics lesson. Suffice it to say thatthe ignition coil is actually a voltage step-upThe Ignition System transformer. Like all transformers, it only transforms~To properly diagnose ignition systems, you needvoltage from its primary windings to its secondaryto have an understanding of how they work and windings when the current flow changes. Sincehow they can affectdrivability. The system x ;:::;K S10 18 2025 30 39 40 49 SO 55 60 63 70 78 SO 859093 vehicle is driven.TCTB [S| si 16 Mercedes-Benz StarTuned 17. ^^3METALLI?t, usaiysa Km% Like Chip Foose, BASF Brings A Little Extra To The Party. lll15iIM:|lfr^iI^llYMVillll^ll(llk1t:to^l^nas oeen doing tne same witn its unique color management system, ie--Ji|KfcajS^^||^Emm^forov tfa: *) t JjKt.*-a i 18. As Good18 Mercedes-Benz StarTuned 19. Chemical ccnding through the use of structural a collision. Automakers are now aware that the mixadhesiyesis not new to the collision industry, but of material choices used to manufacture a vehiclethe need for repair professionals to keep pace requires adhesives that were formulated to matchwith advanced adhesive materials, equipment,the materials being repaired.nq procedures is now on the front burner. Goingp | p r c , khe repair of Mercedes-Benz body panelsModern adhesives are more crash resistantf ^ ^ t i i i e r components demands a commitment to -Applying adhesive is a more complicated process^p(firu":g :e?rring about bonding techniques and than just slathering on some glue and clampingpractices, its also an opportunity. the parts together. Modern automotive structural adhesives are made from chemicals called epoxies,Advanced adhesive f o r m u l a t i o n swhich typically come with two parts, a resin and ]are. availablea catalyst that are kept separate until used. When -Structiurs adhesives are not new; theyve been combined during a repair, the catalyst initiates apBtefrcnone than 25 years in the automobilechemical reaction in the resin. Expect to feel theli|gstf?y. Early adhesives were of the single-bonded parts heating up as the resin develops itscomponent variety, which at that time was sufficient bonding properties and the mixture cures.for some.irepairs involving conventional mild- s^eiigjiksteeis. These yielded to two-componentThe two-stage structural adhesives in use today^aplsh-e formulations that provided improvedinclude polyurethane epoxies, glassy matrix||feTg,.proDerties and allowed more working time. epoxies (which have glass beads embedded in the, v Sty resin), and rubber-based epoxies. Glassy matrixThat was f ne until the materials that vehicles were epoxies are extremely strong and rigid, and they (iriajMactiuiied with began to change in response resist shearing stress - the lateral separationJjljterna^cs for lighter weight, more rigidity, better of the bonded parts - at very high force levels.| f | t e g and environmental performance, improvedPolyurethane epoxies are more flexible and provideS ^. , a r i i d f lower manufacturing costs. To stop the a better fit for some components, but they break ever-inereasii g mass spiral without penalizing safetyunder shearing forces at much lower force levels,andcopfort, automakers have transitioned fromthan glassy matrix epoxies. Newer rubber-based ln^j^ifnilcjtensile-strength steels to lighter weight,adhesives contain additives that allow synergisticMi stronger materials, such as higher-strengthrubber toughening of adhesives to provide high- steels, ofr-er metals (aluminum, magnesium, strength epoxies with greater flexibility - a hybrid of titanium, etc.), thermoplastics, carbon fiber-earlier formulations.K]|fereed plastics, and other composites.iS/^i.Vffji;.:;;. .,-.# :i< , The curing ability is built in to the adhesive, butijKli ;i S-*sW-"/:i1:Sv. "^J; V i ;::.-. -This;omgoing evolution is driving the increased useit requires a lot of testing and some impressivegfe|!ewica1 bonding (using structural adhesives) aschemistry to meet an automakers specifications.she preferred dnd recommended joining method,In some cases, curing may be aided by baking orSlfffif than welding, riveting, or other practices. some other procedure involving applied heat. SomeiMa^afnel [repair instructions, for example, epoxies even cure with the application of ultravioletSpfehoply, prescribe chemical bonding procedures light. Note that the curing times for various (that -use aMesives.adhesives can range from just a few minutes to a day or even longer. Automakers know their vehicles, -But challenges exist for adhesives (as they doso following their collision repair procedures ifpfiptteii Technologies). The reason: High-strength and using the approved resources ensures that||W^.i3,Ndy5.and plastics come in different grades, technicians have adequate working time to effect a: wrijehiiiimpacts how each material performs under- safe, complete repair. various stresses during normal operation and duringFebruary 2012 19 20. As GOOD As NEWFor example, some repairsmay only require a two-stage STRUCTURAL BONDING I RAMPING UP Sadhesive, while others mayrequire the use of adhesives140and rivets - a process known1 2006as rivet-bonding - or theO120//combination of spotwelding.Technicians should note that100 /repairs involving aluminum 1-Ia. 2004should use aluminum rivets,80 /those involving steel shoulduse steel rivets, and that a1 Is 200260coating of zinc dust to preventcorrosion may be required. Beosure to use the number of rivetsI 40 0)specified in Mercedes-Benz21997 |service information.9ni l i i "1996 1998 20002002 20042006Year(Source: Dow Automotive)Chemical bonding Beginning in the mid-1990s, structural adhesives usage began to accelerate. Inprovides stronger and1996, for example, approximately 35 meters of adhesives could be found in a nev/ Mercedes-Benz S-Class model. By 2006, the S-Class had over 135 metersmore durable repairs present. Its continued to grow since and this trend is prevalent in other Mercedes-While based on earlierBenz classe