UNIT3 FUEL INJECTION SYSTEMS TEXT C Troubleshooting the EFI System,PROFESSIONAL ENGLISH,UNIT 3 FUEL INJECTION SYSTEMS TEXT B Troubleshooting the EFI System Engine Condition Electrical System Intake Air Leakage Translation Techniques(3)词类转换,本次课学习内容,本次课学习目标,掌握 EFI系统的故障诊断方法 掌握常用术语，了解相关术语 掌握翻译技巧，提高翻译能力,NEW WORDS,troubleshoot trblu:t v.排除故障 tightness taitnis n.坚固，紧密 integrity integriti n.完整性 concentrate knsntreit v.集中 tune-up tju:np n.调整 tackle tkl v.捉住，从事，对付 dipstick dipstik n.机油尺 canister knist n.罐 purge p: n. & v.排污，排空，清除 clog klg v.堵塞，妨碍；n.障碍（物） faulty f:lti a.报废的，无用的，出故障的，,vent vent v.通风 crankcasekrkkeis n.曲轴箱 probe proub n.探索，探针，探头，取样器 meter mi:t v.计量，测量 proceed prsi:d v.（着手，继续）进行 symptom simptm n.症状，征兆 continuity kntinjuiti n.连通，连续性 leakage li:ki n.泄漏 hesitation hezitein n.迟缓，断续工作 surge s: n.(发动机）喘振，波动，颤抖 clamp klmp n.夹（具，板，子），夹紧装置；卡箍（子） diaphragm daifrm n.膜片,soapy soupia.圆滑的，滑腻的 squirt skw:tv.喷出 gasket gskitn.衬垫 styrofoam stairfoumn.聚苯乙烯泡沫（塑料）,vapor canister 蒸气罐 canister purge valve 炭罐排污阀，炭罐清空阀 false air 从窑炉各处缝隙吸入（炉内）的空气 vacuum hose 真空软管 brake booster 制动助力器 leak detector 检漏器,检漏剂 start by +ing 打开始，（一）开始就（做） strange as it may sound 听说起来也许奇怪,PHRASES AND EXPRESSIONS,Troubleshooting the EFI System The basic function of the fuel injection system is to supply and meter the correct amount of fuel to the engine in proportion to the amount of air being drawn into the engine to achieve the optimum air-fuel mixture. Any problems with electrical connections, air intake sensing, or fuel supply will cause poor running. Any troubleshooting should begin with simple and easy checks of the tightness of system wiring and the integrity of the air intake system. Proceed from there to more involved troubleshooting. Generally, fuel injection problems fall into one of four symptom categories: cold start, cold running, warm running, and hot start. Warm running is the most basic condition. Before troubleshooting a condition in any other category, make sure that the system is working well and is properly adjusted for warm running.,To simplify troubleshooting, concentrate on the sensors and components that adapt fuel metering for a particular condition. For example, if the engine will not start when cold, the components responsible for cold start enrichment are most likely at fault, and should be tested first. Engine Condition The fuel injection system is set to operate on an engine that is in good operating condition. Because the fuel injection system is often the “new item“, some people waste time checking it when the trouble may be with basic engine operation. It is a good idea to use the car manufacturers shop manual to perform a tune-up, and to check the following systems before tackling the fuel injection system. 1. Ignition system. Check timing, including advance and retard control, ignition components and spark quality. 2. Electrical system. Check battery condition and connections, and alternator and voltage regulator.,3. Air intake system. Check the air filter, PCV and crankcase connections, and the evaporative emission connections. A loose oil-filler cap or dipstick can lean the mixture by admitting extra air to the intake manifold through the PCV valve. The vapor canister can enrich the mixture by admitting fuel vapors into the intake manifold through the canister purge valve. 4. Fuel system. A clogged filter may reduce fuel flow. A faulty fuel filler cap or tank vent valve may create gas tank vacuum and reduce fuel flow. Be sure the car has fuel in the tank. 5. Mechanical operation. Check grade and condition of crankcase oil, compression; valve timing, and the exhaust system. Electrical System Whenever working on the wiring, take care to avoid bending any pins or connectors. Use flat pin probes if possible. Inserting the probes of a voltmeter or ohmmeter too far into a wiring connector may spread the contacts and create a new problem.,Relay Set and System Power A faulty relay set may prevent the fuel pump from operating, or prevent power from reaching the control unit. Remove the connector from the relay set, and with the ignition on, check for voltage at the terminals of the connector. If there is voltage, then the relay set is probably faulty, but check the continuity of the wiring to the pump and control unit. Wiring Harness, Connections and Grounds Strange as it may seem, the components of pulsed systems usually give less trouble than the wiring harnesses and connectors that link them. Even small amounts of corrosion or oxidation at the connector terminals can interfere with the small milliamp currents that signal the system to operate. This problem is compounded by the several ground paths provided to insure reliable operation. More than one owner of a “bad“ control unit or component has paid for replacement when the problem was in the wiring. In many cases, cleaning connectors and grounds may s