Engine idle of one.EA837 3.0T fast when engine has abnormal knocking:
1. crankcase vent-pipe and crankcase are ventilated the black O between fine segregator module sealing ring is short of systematic engine oil break or damaged brings about abnormal knocking, change crankcase vent-pipe.
2. crankcase connects air-valve diaphragm damaged to bring about abnormal knocking, change ventilated a powerful person.
3. crankshaft oil seal is not sealed bring about abnormal knocking, change crankshaft oil seal uses diagnostic appearance to undertake leak detects entering enraging a system, with leak detector gush agent undertakes spray in engine and gear-box joint when, see oxygen sensor voltage produces bigger wave motion, sealed place produces seal ring of demonstrative engine crankshaft leak.
Engine idle of 2.EA837 V6 fast when engine has abnormal knocking:
Damaged of 1. crankcase ventiduct brings about abnormal knocking, change ventiduct.
Real case
Breakdown phenomenon:
Car of V6 3.0T EVO uses shift gears pattern in the hand, engine rotate speed is slow the engine when increasing to 3000r/min can give out metallic knock sound, have buzzing noise at the same time, exceed 3000rpm noise to disappear.
Breakdown diagnoses:
According to noise place, judgement comes from mechanical supercharger, it is normal to check mechanical supercharger to work; When urgent cheer make engine rotate speed promotes to 3000r/min, engine movement is normal, without similar abnormal knocking.
Technical analysis:
Graph 1: It is respectively be in in gear-box short switch (engine is urgent quickly, when compulsive downshift) , grow switch with gear-box (slow quickly, exceed rotate speed to restrict) graphic representation. The armature of electromagnetism clutch and rotor begin to contact when engine rotate speed makes an appointment with 3000rpm, the voltaic sensor in engine control unit is beginning to undertake voltaic adjustment right now (the rotate speed of rotor regards an input as signal classics sensor on the synchronous gear that is passed to supercharger) . When short switch, promotion of engine rotate speed is fast, promotion of corresponding supercharger rotate speed is fast, clutch electric current stays in adjust area time is short; When long switch, engine rotate speed is slow promotion, supercharger rotate speed is slow promotion. It is when rotate speed when 3000rpm, electric current is adjusted, bring about electromagnetism clutch abnormal knocking, this abnormal knocking is normal. Exceed 3000rpm, clutch is complete joint, abnormal knocking disappears.
Graph 2: Be supercharger put through and shut characteristic curve; Condition of gules area low torque, clutch come away. Engine rotate speed arrives when 3000rpm clutch joint. Condition of full load of gray area engine, clutch joint.
Abnormal knocking reason sums up:
1. opens engine oil to add the lid that note a mouth, abnormal knocking can produce a change, abnormal knocking reason depends on crankcase ventilated system.
2. negative pressure is exorbitant
The black O of 1 crankcase vent-pipe sealing ring is short of break or damaged
2 crankcase connect air-valve diaphragm damaged
3. negative pressure normal or on the low side
1 crankshaft oil seal is not sealed
Damaged of 2 crankcase ventiduct
Affirm breakdown method:
The local gush chemistry that divulges in the likelihood cleans an agent, see mixture be discouraged period match a value not to have apparent change.
