外文翻譯--電控發(fā)動機常見故障的分析

1、<p>　　畢業(yè)設計(論文)外文資料翻譯</p><p>　　系　　部： 機械工程系 </p><p>　　專 業(yè)： 機械工程及自動化 </p><p>　　姓 名： </p>

2、<p>　　學 號： </p><p>　　外文出處： The Analysis of Engine’s Trouble </p><p>　　附 件： 1.外文資料翻譯譯文；2.外文原文。 </p><p>　　注：請將該封

3、面與附件裝訂成冊。</p><p>　　附件1：外文資料翻譯譯文</p><p>　　電控發(fā)動機常見故障的分析</p><p>　　摘要:各種電子控制系統(tǒng)的使用及其不斷的完善，使得汽車檢測維修技術要求越來越高。本文結合汽車維修的實例，對汽車發(fā)動機電控燃油噴射系統(tǒng)的在維修過程中常見故障的檢測與診斷方法進行分析與探討。 </p><p>　　關鍵

4、詞：電控發(fā)動機、維修、故障、檢測、診斷 </p><p>　　隨著汽車工業(yè)的不斷發(fā)展，汽車制造技術的進步，電子技術在汽車上應用越來越廣泛。電控燃油噴射系統(tǒng)作為汽車的核心組成部分，其性能的好壞直接影響到汽車的動力性、經(jīng)濟性、可靠性、安全性、排放凈化和舒適性。汽車在運行過程中，由于震動，高溫，灰塵等原因，電控燃油噴射系統(tǒng)很可能會出現(xiàn)各種故障。因此，掌握汽車電控系統(tǒng)的保養(yǎng)、故障檢測及排除方法，對保證汽車的正常運行尤為重

5、要。 </p><p>　　一、電控發(fā)動機的組成與工作原理 </p><p>　　發(fā)動機電控汽油噴射系統(tǒng)一般由進氣系統(tǒng)、燃油供給系統(tǒng)、點火系統(tǒng)、控制系統(tǒng)組成。整個電控系統(tǒng)是以發(fā)動機電子控制器(簡稱ECU)為控制核心，以空氣量和發(fā)動機轉速計算出基本噴油持續(xù)時間，根據(jù)傳感器檢測與發(fā)動機工況有關的參數(shù)，對基本噴油持續(xù)時間進行修正，以噴油器，點火電子組件和怠速控制閥等為控制對象，保證獲得與發(fā)動機各

6、種工況相匹配的最佳混合氣成分、噴油時刻和點火時刻。 </p><p>　　二、電控發(fā)動機常見故障及檢修方法分析 </p><p>　　發(fā)動機電控汽油噴射系統(tǒng)只要有油有電，噴油時間和點火時間準確，發(fā)動機便可發(fā)動著火。如果出現(xiàn)故障，在起動發(fā)動機時，可能會出現(xiàn)發(fā)動機難起動、怠速不穩(wěn)或加速不良等現(xiàn)象，這是較常見的故障，原因可能是燃油泵不泵油或泵油量不足、噴油器、冷起動噴嘴及油路堵塞、怠速補償系統(tǒng)不

7、良、水溫傳感器，空氣流量計工作不良及控制電路不良等原因引起。下面以幾個檢修實例來作具體分析： </p><p>　　（一）發(fā)動機起動困難 </p><p><b>　　1、維修實例 </b></p><p>　　車型：上海帕薩特B5轎車。 </p><p>　　故障現(xiàn)象：發(fā)動機熱車時啟動正常，而冷車時，特別是早晨第一次啟

8、動時，啟動困難。 </p><p>　　診斷與排除:從故障癥狀分析，故障應在燃油供給系統(tǒng)。在燃油管上接上專用的燃油壓力表，檢查燃油泵單向閥的密封性，啟動發(fā)動機，檢查燃油系統(tǒng)工作壓力，正常。關閉燃油壓力表上的截止閥，同時停止發(fā)動機工作，此時燃油壓力表上的指示值約為400KP。觀察10min后，壓力約為70KPa，說明系統(tǒng)有泄漏處。 </p><p>　　由于燃油壓力表上的截止閥已關閉，所以分

9、析引起燃油系統(tǒng)泄漏的原因有：（1）燃油泵單向閥泄漏。（2）管路泄漏。 </p><p>　　經(jīng)檢查外部管路無泄漏處，分析應為燃油單向閥泄漏，更換燃油泵后，故障仍未排除。 </p><p>　　分析燃油管路仍有泄漏處。外部管路已檢查過，內部管路呢？檢查油箱內燃油出油口至油箱出油管接頭間的一段透明橡膠管，發(fā)現(xiàn)燃油管上有一處老化裂紋，將此段油管更換后，故障排除。 </p><

10、p>　　2、發(fā)動機起動困難的故障檢測與診斷分析 </p><p><b>　　1）故障現(xiàn)象 </b></p><p>　　發(fā)動機起動困難有兩種主要情況:一是發(fā)動機在溫度低時不易著車，溫度升高時容易著車。二是發(fā)動機冷車起動正常，但熱車后起動時難以起動。 </p><p><b>　　2）故障原因 </b></p&

11、gt;<p>　　燃油系統(tǒng)故障：(1)燃油泵工作不正常；(2)噴油器不良；(3)進氣管路漏真空；(4)怠速控制閥關閉不嚴。 </p><p>　　點火系統(tǒng)故障:(1)空氣流量或進氣壓力傳感器；(2)Ne(轉速信號)G1G2；(3)節(jié)氣門位置，水溫傳感器；(4)空擋NP；(5)點火模塊；(6)點火線圈初級，次級是否斷或短路；(7)高壓線，阻尼電阻或漏電；(8)火花放電間隙是否漏電；(9)檢查ECU是否

12、有故障。 </p><p>　　3）檢測與診斷方法： </p><p>　　(1)測量蓄電池電壓；(2)檢查普助空氣控制閥工作情況；(3)調取故障碼，檢測發(fā)動機溫度傳感器，異常應更換；(4)將發(fā)動機溫度傳感器接頭斷開后起動發(fā)動機，若不正常，檢查溫度傳感器電路及傳感器；(5)檢查調壓管是否堵塞。</p><p>　?。ǘ┌l(fā)動機無快、怠速 </p>&l

13、t;p><b>　　1、維修實例 </b></p><p><b>　　車型：克萊斯勒 </b></p><p>　　故障現(xiàn)象：當?shù)∷俨环€(wěn)或無快怠速并有25號故障碼時，25號故障碼將使CHECKENGINE燈亮。 </p><p><b>　　故障原因：</b></p><p

14、>　?。?）檢查節(jié)氣門本體的導線線束，觀察膠帶捆綁著的任何部位是否絕緣損壞。 </p><p>　　（2）用電線束將導線束牢置于閥蓋上的PCV接頭。 </p><p>　?。?）如果25號故障碼存在，使用SCANNER紅盒子目錄下的CLEARCODES清除故障碼，若故障碼再現(xiàn)，可推測是怠速電機不良或接線松脫。 </p><p>　　2、發(fā)動機無快、怠速的故障檢

15、測與診斷分析 </p><p><b>　　1）故障現(xiàn)象 </b></p><p>　　發(fā)動機啟動后無快、怠速。 </p><p><b>　　2）故障原因 </b></p><p>　　點火系統(tǒng)：點火正時失準。 </p><p>　　進氣系統(tǒng)：（1）旁通進氣管是否堵塞；（2

16、）輔助空氣控制閥工作不正常?？刂葡到y(tǒng)，發(fā)動機水溫傳感器不良。 </p><p><b>　　3）診斷方法 </b></p><p>　?。?）檢查輔助空氣控制閥工作是否正常及其電路；（2）檢查旁通進氣管是否堵塞；（3）檢查并調整點火正時；（4）拔下調壓管真空管，給調壓器提供真空或加壓，檢查混合比反饋傳感系統(tǒng)；（5）拔下發(fā)動機溫度接頭，再啟動，若不正常，檢查傳感器及其電

17、路。 </p><p>　?。ㄈ┌l(fā)動機暖機前怠速不穩(wěn) </p><p><b>　　1、維修實例： </b></p><p>　　車型：豐田皇冠3.0 </p><p>　　故障現(xiàn)象:起動后冷機運轉時，怠速運轉不穩(wěn)。調整怠速螺釘，故障依然存在。 </p><p>　　故障分析與排出：該車裝有電子

18、控制診斷裝置?？捎闷錂z查故障，方法是：打開車頭蓋，在進氣歧管附近找到一個標有Diagnosisde的小盒。開啟診斷的塑料蓋，在其背面插座找到TE1及E1的插孔。用一根短導線連接兩個插孔，然后將點火開關置于ON擋，此時不必啟動發(fā)動機，不必踩油門踏板，使節(jié)氣門保持原位。儀表板上的故障警告燈開始有規(guī)律地閃爍4次和1次，表示故障代碼為41。查閱有關資料，表明節(jié)氣門位置傳感器有故障。 </p><p>　　該車節(jié)氣門位置傳

19、感器為電位計輸出型結構，上有4個接線柱，分別為Vc（電源腳）IDL（怠速腳），VTA（輸出腳）和E2（接地腳）。檢查該傳感器接線沒發(fā)現(xiàn)斷脫，但檢查接插件時發(fā)現(xiàn)其上有銹蝕。對接插件除銹后，電路恢復正常。啟動發(fā)動機，再細調怠速螺釘，其轉速可穩(wěn)定在750r/min左右，消除電腦中的記憶，再復查電腦故障顯示碼，故障顯示碼不再出現(xiàn)，表明故障已排除。最后拆下診斷盒上的短導線即可，該車節(jié)氣門位置傳感器隨著節(jié)氣門轉動而改變電位計上可變電阻，控制器則從變

20、化的電壓信號中得知節(jié)氣門的開度與位置。若節(jié)氣門位置傳感器短路或斷路，都會引起發(fā)動機不易起動，怠速不穩(wěn)或熄火。</p><p>　　2、發(fā)動機暖機前怠速不穩(wěn)的故障檢測與診斷分析 </p><p><b>　　1）故障現(xiàn)象 </b></p><p>　　發(fā)動機啟動后冷機運轉時，怠速運轉不穩(wěn)。 </p><p><b&g

21、t;　　2）故障原因 </b></p><p>　　進氣系統(tǒng)：（1）混合氣濃度，輔助空氣控制閥。 </p><p>　　點火系統(tǒng)：點火正時失準。控制系統(tǒng)：發(fā)動機水溫傳感器不良，EGR系統(tǒng)：EGR控制閥卡住不能關閉，EGR電磁閥常斷。 </p><p><b>　　3）診斷方法 </b></p><p>　?。?/p>

22、1）利用點火正時燈檢查發(fā)動機點火正時；（2）檢查輔助空氣控制閥工作是否正常；（3）拔下油壓調節(jié)器真空管，給調節(jié)器提供真空或加壓，檢查怠速，若有變化，檢查混合比反饋系統(tǒng)；（4）檢查廢氣再循環(huán)控制閥的工作狀況；（5）在發(fā)動機怠速狀態(tài)檢查EGR電磁線圈的端電壓；（6）檢查節(jié)氣門位置傳感器；（7）檢查水溫傳感器及其電路；（8）拔下發(fā)動機水溫傳感器接頭后起動發(fā)動機，檢查怠速運轉情況，若不良，檢查發(fā)動機水溫傳感器及其電路。</p>&

23、lt;p>　　（四）發(fā)動機暖機后怠速過低、不穩(wěn)定 </p><p><b>　　1、維修實例 </b></p><p>　　車型：福特天霸VIN：1FAPD36X5PH121840L42.3L，M/T </p><p>　　故障現(xiàn)象：此車能起動，發(fā)動機啟動后1min就熄火。在熄火前發(fā)動機燈會閃爍幾次，重新起動，發(fā)動機起動后馬上熄火。 &l

24、t;/p><p>　　故障原因：用紅盒子SCANNER掃描儀讀故障碼，也可用手動來讀取。診斷接頭在發(fā)動機防火墻內，將自診斷輸入端（ST1）與信號回輸端以跨線跨接，連接電壓表，正極棒接蓄電池正極，負極棒接自診輸出端（STO），當點火開關ON后，由電壓表擺動的次數(shù)，即可讀取故障碼。清除故障碼，則在點火開關ON后，正要顯示故障碼時，立即拆除跨接線即可，該車讀出的故障碼為進氣溫度傳感器線路不良。 </p>&l

25、t;p>　　故障排除：拆下進氣溫度傳感器，測量其電阻，在不同溫度下應有不同的阻值。 </p><p>　　假如電阻正常，測量信號端電壓源(即25號腳接線)，其電壓應在5V左右。另外，當點火開關OFF時，46號共同搭鐵線與車身搭鐵的電阻應在5歐以下。檢查結果，26號線開路，修好此線路，車輛恢復正常。 </p><p>　　分析：進氣溫度傳感器（ACT）裝在進氣歧管上，或裝在空氣器濾芯旁

26、邊，用以檢測進入氣缸的空氣溫度，以修正噴油量，使空氣燃油的混合比更適合于燃燒。它利用熱敏電阻作感應，將不同的溫度下電阻的變化，轉變成信號電壓。溫度越高，信號電壓越低，噴油量越少。 </p><p>　　2、發(fā)動機暖機后怠速過低、不穩(wěn)定故障檢測與診斷分析 </p><p><b>　　1）故障現(xiàn)象 </b></p><p>　　發(fā)動機暖機后怠速運

27、轉時，轉速過低，容易熄火。 </p><p><b>　　2）故障原因 </b></p><p>　?。?）點火正時過遲，（2）氣缸壓縮力過低，（3）噴油器性能差（4）燃油泵工作狀況不良?？刂葡到y(tǒng)中曲軸位置傳感器，發(fā)動機水溫傳感器不良。 </p><p><b>　　3）診斷方法 </b></p><p

28、>　　（1）用正時燈檢查發(fā)動機點火正時；（2）檢查旁通進氣管是否堵塞；（3）檢查節(jié)氣門室氣路是否堵塞；（4）檢查節(jié)氣門是否卡阻；（5）拔下調壓器真空管，給調壓器提供真空或加壓，檢查發(fā)動機怠速；（6）調取故障碼，利用輸出代碼。</p><p>　?。ㄎ澹┌l(fā)動機加速不良 </p><p><b>　　1、維修實例： </b></p><p>

29、　　車型：別克CENTURY牌轎車，裝備V6電控發(fā)動機。 </p><p>　　故障現(xiàn)象：行駛中加速不良，怠速時嚴重抖動，急加速時進氣管回火。 </p><p><b>　　故障分析與排除： </b></p><p>　　更換火花塞和汽油濾清汽器，清洗空氣濾清器，故障依舊。用汽油噴射系統(tǒng)清洗劑及專用設備自動清洗電噴裝置清洗，仍無效果；拆下噴油器

30、，清洗后故障仍舊。 </p><p>　　拆下空氣濾清器，用手賭住氣門閥體的進口濾網(wǎng)，使主通道的進氣面積減少，增加混合氣濃度，結果怠速穩(wěn)定，加速也不再回火，顯然故障為混合氣過稀所致。 </p><p>　　測試燃油壓力，啟動發(fā)動機并改變轉速，壓力值在正常范圍內。因空氣流量傳感器是影響空燃比的重要因素，拔下其插頭，啟動發(fā)動機，怠速穩(wěn)定，加速性能也良好，故再檢查空氣流量傳感器，接線未斷，但線上

31、有積垢。清除積垢并清洗后復原，故障排除。 </p><p>　　2、發(fā)動機加速不良的故障檢測與診斷分析 </p><p><b>　　1）故障現(xiàn)象 </b></p><p>　　加速時，發(fā)動機轉速不易提高，或發(fā)動機“突突”響。 </p><p>　　2）故障原因及檢修 </p><p>　　燃油系

32、統(tǒng)：（1）燃油管變形；（2）檢測燃油泵工作是否正常；（3）檢測燃油燃油壓力調節(jié)器和保持壓力；（4）檢查噴油器的噴油量和密封性。 </p><p>　　檢查點火系統(tǒng)中火花塞和點火線圈是否損壞，點火正時是否失準。 </p><p>　　電控系統(tǒng)：（1）檢查節(jié)流閥體；（2）進氣歧管轉換閥；（3）凸輪軸調節(jié)電磁閥；（4）發(fā)動機電控單元；（5）傳感器狀態(tài)。 </p><p>

33、　　檢查ECU是否有故障。 </p><p>　　機械系統(tǒng)：（1）汽缸壓力不正常；（2）缸墊沖壞；（3）空氣濾清器堵塞，進氣管路是否漏氣；（4）燃油質量不合格。 </p><p>　　總結：上述為電控發(fā)動機常見故障，每一類故障又表現(xiàn)出不同的故障現(xiàn)象，并且各自有不同的故障原因。當發(fā)動機出現(xiàn)上述常見故障現(xiàn)象，又確定不了故障原因時，應找出每種故障可能的原因，逐一進行排除，直到最后確診并修復。電控

34、汽車故障分析與診斷應遵循“詢問、查閱資料、直觀檢查、調取故障碼、檢測和試驗”檢修過程和規(guī)律，采用逐一排除的方法，將確定故障的范圍一步步縮小，最終找到故障部位。 </p><p>　　隨著汽車技術的不斷發(fā)展，對汽車維修人員的要求也越來越高，汽車維修技術人員只有不斷學習現(xiàn)代汽車技術相關知識和理論，更好的掌握汽車電子控制系統(tǒng)的保養(yǎng)，故障判斷及排除方法，學會使用各種檢測儀器設備，不斷總結維修經(jīng)驗，提高維修技術水平，才能適

35、應汽車維修技術日新月異的發(fā)展。 </p><p>　　附件2：外文原文（復印件）</p><p>　　Electronic Control Engine Troubleshooting Analysis</p><p>　　Abstract: The variety of electronic control system and its constant use

36、of sound, making detection and maintenance technical requirements for motor vehicles getting higher and higher. In this paper, examples of vehicle maintenance on the automobile engine electronic control fuel injection sy

37、stem during maintenance work common fault detection and diagnosis methods of analysis and discussion. </p><p>　　Key words: electronically controlled engine, maintenance, fault detection, diagnosis </p>

38、<p>　　With the continuous development of the automotive industry, automobile manufacturing technology, electronic technology in the automotive application of increasingly wide. Electronic-controlled fuel injection

39、 system as a core component of the vehicle, its performance is a direct impact on the driving force to cars, economy, reliability, safety, emission purification and comfort. Car is running, as a result of vibration, high

40、 temperature, dust and other reasons, electronic-controlled fuel injectio</p><p>　　First, the engine electronic control the composition and working principle </p><p>　　Engine Electronic Control

41、Fuel Injection System General by the intake system, fuel supply system, ignition system, control system. The entire electronic control system is based on the electronic engine controller (ECU) for the control of the core

42、, the air quantity and engine speed to calculate the basic fuel injection duration, according to sensor detection and engine operating conditions on the parameters, the basic fuel injection duration amended so as to fuel

43、 injection, ignition and electroni</p><p>　　Second, Electronic Control Engine Troubleshooting and Maintenance Methods </p><p>　　Engine Electronic Control Fuel Injection System as long as there i

44、s oil has electricity, fuel injection time and ignition time is accurate, the engine can be launched by the fire. If there is a fault in the starter motor, the engine may be difficult to start, idle, such as instability

45、or accelerated undesirable phenomenon, it is a more common fault, probably due to the fuel pump does not pump fuel pump oil or lack of fuel injector , cold-start circuit to plug the nozzle and, bad idle compensatio</p

46、><p>　　(1) engine start-up difficulties</p><p>　　1, maintenance examples </p><p>　　Models: Shanghai Passat B5 sedans. </p><p>　　Fault phenomenon: hot car engine to start n

47、ormally, and when cold, especially in the morning when starting the first time, start difficulties. </p><p>　　Diagnosis and rule out the possibility: from fault symptoms analysis, fault should be in the fuel

48、 supply system. In the fuel pipe connected to a dedicated fuel pressure gauge to check fuel pump check valve leak tightness, start the engine, check fuel system pressure, normal. Close the fuel pressure gauge on the valv

49、e, at the same time work to stop the engine, fuel pressure gauge at this time the instructions on the value of approximately 400KP. Observed after 10min, the pressure is about 70KPa, </p><p>　　As the fuel pr

50、essure gauge on the valve is closed, so analysis of the fuel system leak caused by reasons: (1) fuel pump check valve leaking. (2) pipeline leak. </p><p>　　External pipeline inspection without leakage, the a

51、nalysis should be a one-way valve for the fuel leak, replace the fuel pump, the fault has not yet ruled out. </p><p>　　Analysis of the fuel pipe still leaking Department. External piping has been checked, th

52、e internal pipe it? Check out the oil tank inside the fuel tank out of the mouth to the section of pipeline inter-connector transparent rubber hose and found that the fuel tube has an aging crack, This pipeline will be r

53、eplaced, troubleshooting. </p><p>　　2, engine start-up difficulties of fault detection and diagnosis analysis </p><p>　　1) fault phenomenon </p><p>　　Engine start-up difficulties, t

54、here are two main situations: first, the engine temperature is low is not easy in the car, when temperatures easily the car. Second, cold engine start-up of normal cars, but the hot car difficult to start after the start

55、er. </p><p>　　2) the cause of the malfunction Fuel system failures: (1) fuel pump is not working correctly, (2) bad fuel injector, (3) intake manifold vacuum leak path, (4) Idle Speed Control Valve Close l

56、ax. </p><p>　　Ignition system failure: (1) intake air flow or pressure sensors, (2) Ne (speed signal) G1G2, (3) throttle position, temperature sensors, (4) neutral NP (5) ignition module, (6) ignition coil p

57、rimary, secondary or short-circuit is broken, (7) high-tension line, the damping resistance or leakage, (8) whether the spark discharge gap leakage, (9) to check whether there is any fault ECU. </p><p>　　3)

58、detection and diagnosis methods: </p><p>　　(1) measuring the battery voltage, (2) check the S & P to help the work of the air control valve, (3) access to fault codes, engine temperature sensors detect a

59、bnormal changes should be made, (4) the engine temperature sensor connector will be disconnected after the start-up engine, If normal, check the temperature sensor circuit and sensor, (5) to check whether the plug voltag

60、e regulator tube.</p><p>　　(B) no engine fast idle </p><p>　　1, maintenance examples </p><p>　　Vehicle: Chrysler </p><p>　　Fault phenomenon: when idle or fast idle inst

61、ability and on the 25th when the fault code, fault code on the 25th will CHECKENGINE lights. </p><p>　　Fault reasons: (1) check the throttle body wire harnesses, tape tied observation of whether any part of

62、the damaged insulation. </p><p>　　(2) electric wire harness will be placed in jail beam PCV valve cover joints. </p><p>　　(3) If the fault code exists on the 25th, the use of SCANNER red box dir

63、ectory CLEARCODES clear fault code, if the fault code again, is the idle speed motor may be surmised that a bad or loose wiring. </p><p>　　2, the engine no faster Idle Fault Detection and Diagnostic Analysis

64、 </p><p>　　1) fault phenomenon Start the engine and no fast idle. </p><p>　　2) the cause of the malfunction </p><p>　　Ignition System: ignition timing inaccurate. </p><

65、p>　　Intake System: (1) whether the bypass plug into the trachea (2) auxiliary air control valve is not working correctly. Control systems, engine water temperature sensor bad. </p><p>　　3) diagnostic meth

66、ods </p><p>　　(1) check the auxiliary air control valve work is normal and its circuit, (2) to check whether the plug-pass into the trachea, (3) check and adjust ignition timing, (4) Unplug the vacuum tube r

67、egulator to regulator provide vacuum or pressure, check the mixing ratio feedback sensor system, (5) Unplug the connector engine temperature, and then restart, if it is not normal, check the sensor and its circuit.</p

68、><p>　　(C) warm-up before the engine idle speed instability </p><p>　　1, repair examples: </p><p>　　Vehicle: Toyota Crown 3.0 </p><p>　　Fault phenomenon: after starting ru

69、nning cooler, the idle running unstable. Adjust idle speed screw, fault still exists. </p><p>　　Fault Analysis and discharge: the car equipped with a diagnosis of electronic control devices. Available for th

70、eir inspection</p><p>　　Failure, is: Open bonnet, in the vicinity of air intake manifolds to find a box marked with the Diagnosisde. Open the diagnosis of plastic cover, in its socket to find the back of the

71、 jack TE1 and E1. With a short wire to connect the two jacks, and then placed in the ignition switch ON block, at this time do not have to start the engine, do not have to pedal, so that throttle to maintain in situ. Fau

72、lt dashboard warning lights began flashing regularly 4 times and one times, that fault code 41. C</p><p>　　Car throttle position sensor output for potentiometer-type structure, there are four posts, namely V

73、c (power pin) IDL (Idle feet), VTA (output pin) and E2 (grounding pin). Check the sensor wiring found broken off, but check the connector found on it has corroded. Rust on the connector, the circuit back to normal. Start

74、 the engine, and then fine-tune idle screw, and its speed can be stabilized at around 750r/min, the elimination of computer memory, and then show the code review of computer failur</p><p>　　2, engine warm-up

75、 before the idle instability analysis of fault detection and diagnosis </p><p>　　1) fault phenomenon </p><p>　　Start the engine running after the cooler, the idle running unstable. </p>&

76、lt;p>　　2) the cause of the malfunction </p><p>　　Intake System: (1) mixture concentration, auxiliary air control valve. </p><p>　　Ignition System: ignition timing inaccurate. Control System:

77、Engine water temperature sensor bad, EGR System: EGR control valve jammed shut down should not, EGR solenoid valve often broken. </p><p>　　3) diagnostic methods </p><p>　　(1) the use of ignition

78、 timing light to check the engine ignition timing, (2) check the auxiliary air control valve work is normal, (3) Unplug the oil pressure regulator vacuum tube to the regulator to provide vacuum or pressure, check the idl

79、e speed, if so, what changes, check the mixing ratio feedback system, (4) exhaust gas recirculation control valve to check the status of work, (5) in the engine idling state examination EGR electromagnetic coil terminal

80、voltage, (6) check throttle position </p><p>　　(D) after the engine warm-up idling too low and unstable </p><p>　　1, maintenance examples </p><p>　　Models: Ford Tianba VIN: 1FAPD36X

81、5PH121840L42.3L, M / T </p><p>　　Fault phenomenon: the car can start, start the engine on the flame after 1min. In the flame flickering lantern engine several times before, re-start, engine start-up immediat

82、ely after the flame. </p><p>　　Fault reasons: red box SCANNER scanner read fault codes, can also be used to read the manual. Diagnostic connector in the engine firewall, it will be self-diagnosis input (ST1)

83、 and signal back to lose client to inter-line jumper, connect voltage meter, then the battery anode rod cathode, anode rod from the patient then output (STO), when the ignition switch ON, followed by the number of oscill

84、ating voltage meter, you can read the fault code. Clear fault code, then in the ignition switch ON after</p><p>　　Troubleshooting: Remove intake air temperature sensor, measuring its resistance, at different

85、 temperatures have different resistance. </p><p>　　If the resistance of the normal, measuring signal terminal voltage source (that is, on the 25th pin cable), its voltage should be around 5V. In addition, wh

86、en the ignition switch OFF, the 46 line and the body of common Ground Ground resistance should be below 5 in Europe. Inspection results, on the 26th line of open circuit, repair the lines, the vehicle returned to normal.

87、 </p><p>　　Analysis: intake air temperature sensor (ACT) installed in the intake manifold, or installed in the air beside the filter device to detect air entering the cylinder temperature, to amend the fuel

88、injection quantity, so that the air fuel mixing ratio is more suitable in combustion. It uses thermistor sensors for different temperature resistivity changes into voltage signals. The higher the temperature, the lower v

89、oltage signal, the less amount of fuel injection. </p><p>　　2, the engine idle speed is too low after warm-up, unstable fault detection and diagnosis analysis </p><p>　　1) fault phenomenon </

90、p><p>　　Engine Idling after warm-up operation, the speed is too low, easy to flame. </p><p>　　2) the cause of the malfunction </p><p>　　(1) late ignition timing, (2) Cylinder compressi

91、on force is too low, (3) poor performance Injector (4) working conditions, bad fuel pump. Control system of the crankshaft position sensor, engine water temperature sensor bad. </p><p>　　3) diagnostic method

92、s </p><p>　　(1) check engine light is when the ignition timing, (2) to check whether the plug-pass into the trachea, (3) to check whether the gas chamber throttle plug (4) check whether the card throttle res

93、istance, (5) pull down voltage vacuum tube to the regulator to provide vacuum or pressure, check engine idle speed, (6) access to fault codes, the use of the output code</p><p>　　(E) of the engine to acceler

94、ate the adverse </p><p>　　1, repair examples:</p><p>　　Models: Buick CENTURY sedans equipped V6 engine electronic control. </p><p>　　Fault phenomenon: moving to accelerate the poor

95、idle when serious jitter, when the intake manifold backfire. </p><p>　　Troubleshooting: </p><p>　　Replacement of spark plugs and gasoline vapor filter, and clean air filter, fault still. Petrol

96、injection system cleaning agents and special equipment EFI automatic cleaning device cleaning, no effect; removed injector, fault remains after cleaning. </p><p>　　Removed the air filter, hand gambling live

97、import filter valve body so that the main channel to reduce the intake area, increasing the concentration of the mixture, resulting in idle stability, not speed up the return fire, apparently as a mixture over fault Dilu

98、te due. </p><p>　　Testing fuel pressure, start the engine and change speed, the pressure value in the normal range. Due to air flow sensor is an important factor in the impact of air-fuel ratio, unplug the p

99、lug, start the engine, idle speed stability, and speed up performance is also good, so check the air flow sensor, wiring is not broken, but online has fouling. Removal of fouling and cleaning after the recovery, troubles

100、hooting. </p><p>　　2, the engine speed up the bad fault detection and diagnosis analysis </p><p>　　1) fault phenomenon </p><p>　　Accelerate when the engine speed is not easy to rais

101、e, or the engine "chug" sound. </p><p>　　2) the cause of the malfunction and repair </p><p>　　Fuel system: (1) fuel tube deformation, (2) testing the fuel pump work is normal, (3) test

102、ing the fuel pressure regulator fuel and maintain the pressure, (4) to check the fuel injection injector and tightness. </p><p>　　Check the ignition system and ignition coil spark plug is damaged, the igniti

103、on timing is inaccurate. </p><p>　　Electronic Control System: (1) check the throttle body, (2) Intake Manifold switching valve, (3) solenoid valve camshaft adjustment, (4) Engine electronic control unit, (5)

104、 sensor status.</p><p>　　ECU has to check whether the fault. </p><p>　　Mechanical systems: (1) the cylinder pressure is not normal, (2) cylinder pad washed out, (3) air filter blocked the road w