外文翻譯電控發(fā)動機(jī)常見故障的分析

1、畢業(yè)設(shè)計(jì)(論文)外文資料翻譯系部： 機(jī)械工程系 專 業(yè)： 機(jī)械工程及自動化 姓 名： 學(xué) 號： (用外文寫)外文出處： the analysis of engines trouble 附 件： 1.外文資料翻譯譯文；2.外文原文。 指導(dǎo)教師評語： 譯文基本能翻譯表達(dá)出原文的內(nèi)容，條理較為分明，語句基本通順，總體譯文質(zhì)量尚可，但少數(shù)專業(yè)術(shù)語翻譯不夠準(zhǔn)確，一些語句比較生硬。 簽名： 年 月 日注：請將該封面與附件裝訂成冊。附件1：外文資料翻譯譯文電控發(fā)動機(jī)常見故障的分析摘要: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(shù)要求越來越高。本文結(jié)合汽車維修的實(shí)例，對汽車發(fā)動機(jī)電控燃油噴射系統(tǒng)

2、的在維修過程中常見故障的檢測與診斷方法進(jìn)行分析與探討。 關(guān)鍵詞：電控發(fā)動機(jī)、維修、故障、檢測、診斷 隨著汽車工業(yè)的不斷發(fā)展，汽車制造技術(shù)的進(jìn)步，電子技術(shù)在汽車上應(yīng)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(jì)性、可靠性、安全性、排放凈化和舒適性。汽車在運(yùn)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(yùn)行尤為重要。 一、電控發(fā)動機(jī)的組成與工作原理 發(fā)動機(jī)電控汽油噴射系統(tǒng)一般由進(jìn)氣系統(tǒng)、燃油供給系統(tǒng)、點(diǎn)火系統(tǒng)、控制系統(tǒng)組成。整個電控系統(tǒng)是以發(fā)動機(jī)電子控制器

3、(簡稱ecu)為控制核心，以空氣量和發(fā)動機(jī)轉(zhuǎn)速計(jì)算出基本噴油持續(xù)時間，根據(jù)傳感器檢測與發(fā)動機(jī)工況有關(guān)的參數(shù)，對基本噴油持續(xù)時間進(jìn)行修正，以噴油器，點(diǎn)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(jī)各種工況相匹配的最佳混合氣成分、噴油時刻和點(diǎn)火時刻。 二、電控發(fā)動機(jī)常見故障及檢修方法分析 發(fā)動機(jī)電控汽油噴射系統(tǒng)只要有油有電，噴油時間和點(diǎn)火時間準(zhǔn)確，發(fā)動機(jī)便可發(fā)動著火。如果出現(xiàn)故障，在起動發(fā)動機(jī)時，可能會出現(xiàn)發(fā)動機(jī)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(bǔ)償系統(tǒng)不良、水溫傳感器，空氣流量計(jì)工作不良及控制電路不良等

4、原因引起。下面以幾個檢修實(shí)例來作具體分析： （一）發(fā)動機(jī)起動困難 1、維修實(shí)例 車型：上海帕薩特b5轎車。 故障現(xiàn)象：發(fā)動機(jī)熱車時啟動正常，而冷車時，特別是早晨第一次啟動時，啟動困難。 診斷與排除:從故障癥狀分析，故障應(yīng)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(jī)，檢查燃油系統(tǒng)工作壓力，正常。關(guān)閉燃油壓力表上的截止閥，同時停止發(fā)動機(jī)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。 由于燃油壓力表上的截止閥已關(guān)閉，所以分析引起燃油系統(tǒng)泄漏的原因有：（1）燃油泵單向閥泄漏。（2）管路泄漏。 經(jīng)檢查外部管路

5、無泄漏處，分析應(yīng)為燃油單向閥泄漏，更換燃油泵后，故障仍未排除。 分析燃油管路仍有泄漏處。外部管路已檢查過，內(nèi)部管路呢？檢查油箱內(nèi)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。 2、發(fā)動機(jī)起動困難的故障檢測與診斷分析 1）故障現(xiàn)象 發(fā)動機(jī)起動困難有兩種主要情況:一是發(fā)動機(jī)在溫度低時不易著車，溫度升高時容易著車。二是發(fā)動機(jī)冷車起動正常，但熱車后起動時難以起動。 2）故障原因 燃油系統(tǒng)故障：(1)燃油泵工作不正常；(2)噴油器不良；(3)進(jìn)氣管路漏真空；(4)怠速控制閥關(guān)閉不嚴(yán)。 點(diǎn)火系統(tǒng)故障:(1)空氣流量或進(jìn)氣壓力傳感器；(2)ne(轉(zhuǎn)速信

6、號)g1g2；(3)節(jié)氣門位置，水溫傳感器；(4)空擋np；(5)點(diǎn)火模塊；(6)點(diǎn)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是否有故障。 3）檢測與診斷方法： (1)測量蓄電池電壓；(2)檢查普助空氣控制閥工作情況；(3)調(diào)取故障碼，檢測發(fā)動機(jī)溫度傳感器，異常應(yīng)更換；(4)將發(fā)動機(jī)溫度傳感器接頭斷開后起動發(fā)動機(jī)，若不正常，檢查溫度傳感器電路及傳感器；(5)檢查調(diào)壓管是否堵塞。（二）發(fā)動機(jī)無快、怠速 1、維修實(shí)例 車型：克萊斯勒 故障現(xiàn)象：當(dāng)?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。 故障原因

7、：（1）檢查節(jié)氣門本體的導(dǎo)線線束，觀察膠帶捆綁著的任何部位是否絕緣損壞。 （2）用電線束將導(dǎo)線束牢置于閥蓋上的pcv接頭。 （3）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(jī)不良或接線松脫。 2、發(fā)動機(jī)無快、怠速的故障檢測與診斷分析 1）故障現(xiàn)象 發(fā)動機(jī)啟動后無快、怠速。 2）故障原因 點(diǎn)火系統(tǒng)：點(diǎn)火正時失準(zhǔn)。 進(jìn)氣系統(tǒng)：（1）旁通進(jìn)氣管是否堵塞；（2）輔助空氣控制閥工作不正常?？刂葡到y(tǒng)，發(fā)動機(jī)水溫傳感器不良。 3）診斷方法 （1）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(jìn)氣管是否堵塞；（3）檢查并調(diào)整點(diǎn)火正

8、時；（4）拔下調(diào)壓管真空管，給調(diào)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(jī)溫度接頭，再啟動，若不正常，檢查傳感器及其電路。 （三）發(fā)動機(jī)暖機(jī)前怠速不穩(wěn) 1、維修實(shí)例： 車型：豐田皇冠3.0 故障現(xiàn)象:起動后冷機(jī)運(yùn)轉(zhuǎn)時，怠速運(yùn)轉(zhuǎn)不穩(wěn)。調(diào)整怠速螺釘，故障依然存在。 故障分析與排出：該車裝有電子控制診斷裝置?？捎闷錂z查故障，方法是：打開車頭蓋，在進(jìn)氣歧管附近找到一個標(biāo)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(dǎo)線連接兩個插孔，然后將點(diǎn)火開關(guān)置于on擋，此時不必啟動發(fā)動機(jī)，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

9、規(guī)律地閃爍4次和1次，表示故障代碼為41。查閱有關(guān)資料，表明節(jié)氣門位置傳感器有故障。 該車節(jié)氣門位置傳感器為電位計(jì)輸出型結(jié)構(gòu)，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(fù)正常。啟動發(fā)動機(jī)，再細(xì)調(diào)怠速螺釘，其轉(zhuǎn)速可穩(wěn)定在750r/min左右，消除電腦中的記憶，再復(fù)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(dǎo)線即可，該車節(jié)氣門位置傳感器隨著節(jié)氣門轉(zhuǎn)動而改變電位計(jì)上可變電阻，控制器則從變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

10、路或斷路，都會引起發(fā)動機(jī)不易起動，怠速不穩(wěn)或熄火。2、發(fā)動機(jī)暖機(jī)前怠速不穩(wěn)的故障檢測與診斷分析 1）故障現(xiàn)象 發(fā)動機(jī)啟動后冷機(jī)運(yùn)轉(zhuǎn)時，怠速運(yùn)轉(zhuǎn)不穩(wěn)。 2）故障原因 進(jìn)氣系統(tǒng)：（1）混合氣濃度，輔助空氣控制閥。 點(diǎn)火系統(tǒng)：點(diǎn)火正時失準(zhǔn)?？刂葡到y(tǒng)：發(fā)動機(jī)水溫傳感器不良，egr系統(tǒng)：egr控制閥卡住不能關(guān)閉，egr電磁閥常斷。 3）診斷方法 （1）利用點(diǎn)火正時燈檢查發(fā)動機(jī)點(diǎn)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(diào)節(jié)器真空管，給調(diào)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(jī)怠速狀態(tài)檢查egr電磁線圈的端電壓；（6

11、）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(jī)水溫傳感器接頭后起動發(fā)動機(jī)，檢查怠速運(yùn)轉(zhuǎn)情況，若不良，檢查發(fā)動機(jī)水溫傳感器及其電路。（四）發(fā)動機(jī)暖機(jī)后怠速過低、不穩(wěn)定 1、維修實(shí)例 車型：福特天霸vin：1fapd36x5ph121840l42.3l，m/t 故障現(xiàn)象：此車能起動，發(fā)動機(jī)啟動后1min就熄火。在熄火前發(fā)動機(jī)燈會閃爍幾次，重新起動，發(fā)動機(jī)起動后馬上熄火。 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(jī)防火墻內(nèi)，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(fù)極棒接自診輸出端（sto），當(dāng)點(diǎn)

12、火開關(guān)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(diǎn)火開關(guān)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(jìn)氣溫度傳感器線路不良。 故障排除：拆下進(jìn)氣溫度傳感器，測量其電阻，在不同溫度下應(yīng)有不同的阻值。 假如電阻正常，測量信號端電壓源(即25號腳接線)，其電壓應(yīng)在5v左右。另外，當(dāng)點(diǎn)火開關(guān)off時，46號共同搭鐵線與車身搭鐵的電阻應(yīng)在5歐以下。檢查結(jié)果，26號線開路，修好此線路，車輛恢復(fù)正常。 分析：進(jìn)氣溫度傳感器（act）裝在進(jìn)氣歧管上，或裝在空氣器濾芯旁邊，用以檢測進(jìn)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(yīng)，將不同

13、的溫度下電阻的變化，轉(zhuǎn)變成信號電壓。溫度越高，信號電壓越低，噴油量越少。 2、發(fā)動機(jī)暖機(jī)后怠速過低、不穩(wěn)定故障檢測與診斷分析 1）故障現(xiàn)象 發(fā)動機(jī)暖機(jī)后怠速運(yùn)轉(zhuǎn)時，轉(zhuǎn)速過低，容易熄火。 2）故障原因 （1）點(diǎn)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。控制系統(tǒng)中曲軸位置傳感器，發(fā)動機(jī)水溫傳感器不良。 3）診斷方法 （1）用正時燈檢查發(fā)動機(jī)點(diǎn)火正時；（2）檢查旁通進(jìn)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(diào)壓器真空管，給調(diào)壓器提供真空或加壓，檢查發(fā)動機(jī)怠速；（6）調(diào)取故障碼，利用輸出代碼。（五）發(fā)動機(jī)加速不良 1、維修實(shí)

14、例： 車型：別克century牌轎車，裝備v6電控發(fā)動機(jī)。 故障現(xiàn)象：行駛中加速不良，怠速時嚴(yán)重抖動，急加速時進(jìn)氣管回火。 故障分析與排除： 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(shè)備自動清洗電噴裝置清洗，仍無效果；拆下噴油器，清洗后故障仍舊。 拆下空氣濾清器，用手賭住氣門閥體的進(jìn)口濾網(wǎng)，使主通道的進(jìn)氣面積減少，增加混合氣濃度，結(jié)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。 測試燃油壓力，啟動發(fā)動機(jī)并改變轉(zhuǎn)速，壓力值在正常范圍內(nèi)。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(jī)，怠速穩(wěn)定，加速性能也良好，故再檢查空氣流量傳感器，接

15、線未斷，但線上有積垢。清除積垢并清洗后復(fù)原，故障排除。 2、發(fā)動機(jī)加速不良的故障檢測與診斷分析 1）故障現(xiàn)象 加速時，發(fā)動機(jī)轉(zhuǎn)速不易提高，或發(fā)動機(jī)“突突”響。 2）故障原因及檢修 燃油系統(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(diào)節(jié)器和保持壓力；（4）檢查噴油器的噴油量和密封性。 檢查點(diǎn)火系統(tǒng)中火花塞和點(diǎn)火線圈是否損壞，點(diǎn)火正時是否失準(zhǔn)。 電控系統(tǒng)：（1）檢查節(jié)流閥體；（2）進(jìn)氣歧管轉(zhuǎn)換閥；（3）凸輪軸調(diào)節(jié)電磁閥；（4）發(fā)動機(jī)電控單元；（5）傳感器狀態(tài)。 檢查ecu是否有故障。 機(jī)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(jìn)氣管路是否漏

16、氣；（4）燃油質(zhì)量不合格。 總結(jié)：上述為電控發(fā)動機(jī)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(dāng)發(fā)動機(jī)出現(xiàn)上述常見故障現(xiàn)象，又確定不了故障原因時，應(yīng)找出每種故障可能的原因，逐一進(jìn)行排除，直到最后確診并修復(fù)。電控汽車故障分析與診斷應(yīng)遵循“詢問、查閱資料、直觀檢查、調(diào)取故障碼、檢測和試驗(yàn)”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。 隨著汽車技術(shù)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(shù)人員只有不斷學(xué)習(xí)現(xiàn)代汽車技術(shù)相關(guān)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(xué)會使用各種檢測儀器設(shè)備，不斷總結(jié)維修

17、經(jīng)驗(yàn)，提高維修技術(shù)水平，才能適應(yīng)汽車維修技術(shù)日新月異的發(fā)展。 附件2：外文原文（復(fù)印件）electronic control engine troubleshooting analysisabstract: the variety of electronic control system and its constant use of sound, making detection and maintenance technical requirements for motor vehicles getting higher and higher. in this paper, example

18、s of vehicle maintenance on the automobile engine electronic control fuel injection system during maintenance work common fault detection and diagnosis methods of analysis and discussion. key words: electronically controlled engine, maintenance, fault detection, diagnosis with the continuous develop

19、ment of the automotive industry, automobile manufacturing technology, electronic technology in the automotive application of increasingly wide. electronic-controlled fuel injection system as a core component of the vehicle, its performance is a direct impact on the driving force to cars, economy, re

20、liability, safety, emission purification and comfort. car is running, as a result of vibration, high temperature, dust and other reasons, electronic-controlled fuel injection system will probably give rise to a variety of failures. therefore, the master automotive electronic control system maintenan

21、ce, fault detection and troubleshooting, to ensure the normal operation of motor vehicles is particularly important. first, the engine electronic control the composition and working principle engine electronic control fuel injection system general by the intake system, fuel supply system, ignition s

22、ystem, control system. the entire electronic control system is based on the electronic engine controller (ecu) for the control of the core, the air quantity and engine speed to calculate the basic fuel injection duration, according to sensor detection and engine operating conditions on the parameter

23、s, the basic fuel injection duration amended so as to fuel injection, ignition and electronic components, such as idle speed control valve to control the object, to guarantee access to a variety of working conditions with the engine to match the best mixture components, fuel injection time and ignit

24、ion time. second, electronic control engine troubleshooting and maintenance methods engine electronic control fuel injection system as long as there is 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 m

25、otor, the engine may be difficult to start, idle, such as instability 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 compensation system, water

26、temperature sensors, air flow meter and control the work of non-performing circuit caused bad. below a few examples of maintenance for a specific analysis:(1) engine start-up difficulties 1, maintenance examples models: shanghai passat b5 sedans. fault phenomenon: hot car engine to start normally, a

27、nd when cold, especially in the morning when starting the first time, start difficulties. diagnosis and rule out the possibility: from fault symptoms analysis, fault should be in the fuel supply system. in the fuel pipe connected to a dedicated fuel pressure gauge to check fuel pump check valve leak

28、 tightness, start the engine, check fuel system pressure, normal. close the fuel pressure gauge on the valve, 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, note the s

29、ystem has leaked department. as the fuel pressure 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. external pipeline inspection without leakage, the analysis should be a one-way valve for the fuel leak, replace

30、 the fuel pump, the fault has not yet ruled out. analysis of the fuel pipe still leaking department. external piping has been checked, the 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

31、the fuel tube has an aging crack, this pipeline will be replaced, troubleshooting. 2, engine start-up difficulties of fault detection and diagnosis analysis 1) fault phenomenon engine start-up difficulties, there are two main situations: first, the engine temperature is low is not easy in the car, w

32、hen temperatures easily the car. second, cold engine start-up of normal cars, but the hot car difficult to start after the starter. 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 spee

33、d control valve close lax. 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 primary, secondary or short-circuit is broken, (7) high-tension line, the damping

34、 resistance or leakage, (8) whether the spark discharge gap leakage, (9) to check whether there is any fault ecu. 3) detection and diagnosis methods: (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 sensor

35、s detect abnormal 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 voltage regulator tube.(b) no engine fast idle 1, maintenance examples vehic

36、le: chrysler fault phenomenon: when idle or fast idle instability and on the 25th when the fault code, fault code on the 25th will checkengine lights. fault reasons: (1) check the throttle body wire harnesses, tape tied observation of whether any part of the damaged insulation. (2) electric wire har

37、ness will be placed in jail beam pcv valve cover joints. (3) if the fault code exists on the 25th, the use of scanner red box directory clearcodes clear fault code, if the fault code again, is the idle speed motor may be surmised that a bad or loose wiring. 2, the engine no faster idle fault detecti

38、on and diagnostic analysis 1) fault phenomenon start the engine and no fast idle. 2) the cause of the malfunction ignition system: ignition timing inaccurate. intake system: (1) whether the bypass plug into the trachea (2) auxiliary air control valve is not working correctly. control systems, engine

39、 water temperature sensor bad. 3) diagnostic methods (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 regulator to regulator provide vacuum or pressure, chec

40、k 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.(c) warm-up before the engine idle speed instability 1, repair examples: vehicle: toyota crown 3.0 fault phenomenon: after starting running

41、cooler, the idle running unstable. adjust idle speed screw, fault still exists. fault analysis and discharge: the car equipped with a diagnosis of electronic control devices. available for their inspection failure, is: open bonnet, in the vicinity of air intake manifolds to find a box marked with th

42、e diagnosisde. open the diagnosis of plastic cover, in its socket to find the back of the 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

43、situ. fault dashboard warning lights began flashing regularly 4 times and one times, that fault code 41. check out the information that has throttle position sensor fault. car throttle position sensor output for potentiometer-type structure, there are four posts, namely vc (power pin) idl (idle feet

44、), 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 the engine, and then fine-tune idle screw, and its speed can be stabilized at around 750r/min, the eliminat

45、ion of computer memory, and then show the code review of computer failures, fault display code no longer appears that the fault has been ruled out. finally removed the diagnosis box on the wires can be short, the car throttle position sensor with the throttle while turning the potentiometer to chang

46、e the variable resistor, the controller changes the voltage signal from that a throttle opening and position. if the throttle position sensor short circuit or open circuit will cause the engine difficult to start, idle, or flame instability. 2, engine warm-up before the idle instability analysis of

47、fault detection and diagnosis 1) fault phenomenon start the engine running after the cooler, the idle running unstable. 2) the cause of the malfunction intake system: (1) mixture concentration, auxiliary air control valve. ignition system: ignition timing inaccurate. control system: engine water tem

48、perature sensor bad, egr system: egr control valve jammed shut down should not, egr solenoid valve often broken. 3) diagnostic methods (1) the use of ignition timing light to check the engine ignition timing, (2) check the auxiliary air control valve work is normal, (3) unplug the oil pressure regul

49、ator vacuum tube to the regulator to provide vacuum or pressure, check the idle 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 vo

50、ltage, (6) check throttle position sensor, (7) check the water temperature sensor and its circuit, (8) unplug the engine temperature sensor connector after the start-up engine, check the idle speed operation, and if bad, check engine temperature sensor and its circuit. (d) after the engine warm-up i

51、dling too low and unstable 1, maintenance examples models: ford tianba vin: 1fapd36x5ph121840l42.3l, m / t 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 immediately after the flame

52、. 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) and signal back to lose client to inter-line jumper, connect voltage meter, then the battery anode rod cathode, anode rod

53、 from the patient then output (sto), when the ignition switch on, followed by the number of oscillating voltage meter, you can read the fault code. clear fault code, then in the ignition switch on after the fault code when going to shows, cross-wiring can be dismantled immediately, car fault code re

54、ad out for the intake air temperature sensor circuit bad. troubleshooting: remove intake air temperature sensor, measuring its resistance, at different temperatures have different resistance. if the resistance of the normal, measuring signal terminal voltage source (that is, on the 25th pin cable),

55、its voltage should be around 5v. in addition, when 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. analysis: intake air temperatur

56、e 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 injection quantity, so that the air fuel mixing ratio is more suitable in combustion. it uses thermistor sensors for different temperat

57、ure resistivity changes into voltage signals. the higher the temperature, the lower voltage signal, the less amount of fuel injection. 2, the engine idle speed is too low after warm-up, unstable fault detection and diagnosis analysis 1) fault phenomenon engine idling after warm-up operation, the speed is too low, easy to flame. 2) the cause of the malfunction (1) late ignition timing, (2) cylinder compression force is too low, (3) poor performance injector (4) working conditions, bad fuel pump. control system of the crankshaft position s