外文翻译电控发动机常见故障的分析

《外文翻译电控发动机常见故障的分析》由会员分享，可在线阅读，更多相关《外文翻译电控发动机常见故障的分析（21页珍藏版）》请在装配图网上搜索。

1、外文翻译电控发动机常见故障的分析毕业设计(论文)外文资料翻译 系 部： 机械工程系 专 业： 机械工程及自动化 姓 名： 学 号： 外文出处： The Analysis of Engines Trouble (用外文写) 附 件： 1.外文资料翻译译文；2.外文原文。 指导教师评语： 译文基本能翻译表达出原文的内容，条理较为分明，语句基本通顺，总体译文质量尚可，但少数专业术语翻译不够准确，一些语句比较生硬。 签名： 年 月 日 注：请将该封面与附件装订成册。 附件1：外文资料翻译译文 电控发动机常见故障的分析 摘要:各种电子控制系统的使用及其不断的完善，使得汽车检测维修技术要求越来越高。本文结

2、合汽车维修的实例，对汽车发动机电控燃油喷射系统的在维修过程中常见故障的检测与诊断方法进行分析与探讨。 关键词：电控发动机、维修、故障、检测、诊断 随着汽车工业的不断发展，汽车制造技术的进步，电子技术在汽车上应用越来越广泛。电控燃油喷射系统作为汽车的核心组成部分，其性能的好坏直接影响到汽车的动力性、经济性、可靠性、安全性、排放净化和舒适性。汽车在运行过程中，由于震动，高温，灰尘等原因，电控燃油喷射系统很可能会出现各种故障。因此，掌握汽车电控系统的保养、故障检测及排除方法，对保证汽车的正常运行尤为重要。 一、电控发动机的组成与工作原理 发动机电控汽油喷射系统一般由进气系统、燃油供给系统、点火系统、

3、控制系统组成。整个电控系统是以发动机电子控制器(简称ECU)为控制核心，以空气量和发动机转速计算出基本喷油持续时间，根据传感器检测与发动机工况有关的参数，对基本喷油持续时间进行修正，以喷油器，点火电子组件和怠速控制阀等为控制对象，保证获得与发动机各种工况相匹配的最佳混合气成分、喷油时刻和点火时刻。 二、电控发动机常见故障及检修方法分析 发动机电控汽油喷射系统只要有油有电，喷油时间和点火时间准确，发动机便可发动着火。如果出现故障，在起动发动机时，可能会出现发动机难起动、怠速不稳或加速不良等现象，这是较常见的故障，原因可能是燃油泵不泵油或泵油量不足、喷油器、冷起动喷嘴及油路堵塞、怠速补偿系统不良、

4、水温传感器，空气流量计工作不良及控制电路不良等原因引起。下面以几个检修实例来作具体分析： 发动机起动困难 1、维修实例 车型：上海帕萨特B5轿车。 故障现象：发动机热车时启动正常，而冷车时，特别是早晨第一次启动时，启动困难。 诊断与排除:从故障症状分析，故障应在燃油供给系统。在燃油管上接上专用的燃油压力表，检查燃油泵单向阀的密封性，启动发动机，检查燃油系统工作压力，正常。关闭燃油压力表上的截止阀，同时停止发动机工作，此时燃油压力表上的指示值约为400KP。观察10min后，压力约为70KPa，说明系统有泄漏处。 由于燃油压力表上的截止阀已关闭，所以分析引起燃油系统泄漏的原因有：燃油泵单向阀泄漏

5、。管路泄漏。 经检查外部管路无泄漏处，分析应为燃油单向阀泄漏，更换燃油泵后，故障仍未排除。 分析燃油管路仍有泄漏处。外部管路已检查过，内部管路呢？检查油箱内燃油出油口至油箱出油管接头间的一段透明橡胶管，发现燃油管上有一处老化裂纹，将此段油管更换后，故障排除。 2、发动机起动困难的故障检测与诊断分析 1）故障现象 发动机起动困难有两种主要情况:一是发动机在温度低时不易着车，温度升高时容易着车。二是发动机冷车起动正常，但热车后起动时难以起动。 2）故障原因 燃油系统故障：(1)燃油泵工作不正常；(2)喷油器不良；(3)进气管路漏真空；(4)怠速控制阀关闭不严。 点火系统故障:(1)空气流量或进气压

6、力传感器；(2)Ne(转速信号)G1G2；(3)节气门位置，水温传感器；(4)空挡NP；(5)点火模块；(6)点火线圈初级，次级是否断或短路；(7)高压线，阻尼电阻或漏电；(8)火花放电间隙是否漏电；(9)检查ECU是否有故障。 3）检测与诊断方法： (1)测量蓄电池电压；(2)检查普助空气控制阀工作情况；(3)调取故障码，检测发动机温度传感器，异常应更换；(4)将发动机温度传感器接头断开后起动发动机，若不正常，检查温度传感器电路及传感器；(5)检查调压管是否堵塞。 发动机无快、怠速 1、维修实例 车型：克莱斯勒 故障现象：当怠速不稳或无快怠速并有25号故障码时，25号故障码将使CHECKEN

7、GINE灯亮。 故障原因： 检查节气门本体的导线线束，观察胶带捆绑着的任何部位是否绝缘损坏。 用电线束将导线束牢置于阀盖上的PCV接头。 如果25号故障码存在，使用SCANNER红盒子目录下的CLEARCODES清除故障码，若故障码再现，可推测是怠速电机不良或接线松脱。 2、发动机无快、怠速的故障检测与诊断分析 1）故障现象 发动机启动后无快、怠速。 2）故障原因 点火系统：点火正时失准。 进气系统：旁通进气管是否堵塞；辅助空气控制阀工作不正常。控制系统，发动机水温传感器不良。 3）诊断方法 检查辅助空气控制阀工作是否正常及其电路；检查旁通进气管是否堵塞；检查并调整点火正时；拔下调压管真空管，

8、给调压器提供真空或加压，检查混合比反馈传感系统；拔下发动机温度接头，再启动，若不正常，检查传感器及其电路。 发动机暖机前怠速不稳 1、维修实例： 车型：丰田皇冠3.0 故障现象:起动后冷机运转时，怠速运转不稳。调整怠速螺钉，故障依然存在。 故障分析与排出：该车装有电子控制诊断装置。可用其检查故障，方法是：打开车头盖，在进气歧管附近找到一个标有Diagnosisde的小盒。开启诊断的塑料盖，在其背面插座找到TE1及E1的插孔。用一根短导线连接两个插孔，然后将点火开关置于ON挡，此时不必启动发动机，不必踩油门踏板，使节气门保持原位。仪表板上的故障警告灯开始有规律地闪烁4次和1次，表示故障代码为41

9、。查阅有关资料，表明节气门位置传感器有故障。 该车节气门位置传感器为电位计输出型结构，上有4个接线柱，分别为VcIDL，VTA和E2。检查该传感器接线没发现断脱，但检查接插件时发现其上有锈蚀。对接插件除锈后，电路恢复正常。启动发动机，再细调怠速螺钉，其转速可稳定在750r/min左右，消除电脑中的记忆，再复查电脑故障显示码，故障显示码不再出现，表明故障已排除。最后拆下诊断盒上的短导线即可，该车节气门位置传感器随着节气门转动而改变电位计上可变电阻，控制器则从变化的电压信号中得知节气门的开度与位置。若节气门位置传感器短路或断路，都会引起发动机不易起动，怠速不稳或熄火。 2、发动机暖机前怠速不稳的故

10、障检测与诊断分析 1）故障现象 发动机启动后冷机运转时，怠速运转不稳。 2）故障原因 进气系统：混合气浓度，辅助空气控制阀。 点火系统：点火正时失准。控制系统：发动机水温传感器不良，EGR系统：EGR控制阀卡住不能关闭，EGR电磁阀常断。 3）诊断方法 利用点火正时灯检查发动机点火正时；检查辅助空气控制阀工作是否正常；拔下油压调节器真空管，给调节器提供真空或加压，检查怠速，若有变化，检查混合比反馈系统；检查废气再循环控制阀的工作状况；在发动机怠速状态检查EGR电磁线圈的端电压；检查节气门位置传感器；检查水温传感器及其电路；拔下发动机水温传感器接头后起动发动机，检查怠速运转情况，若不良，检查发动

11、机水温传感器及其电路。 发动机暖机后怠速过低、不稳定 1、维修实例 车型：福特天霸VIN：1FAPD36X5PH121840L42.3L，M/T 故障现象：此车能起动，发动机启动后1min就熄火。在熄火前发动机灯会闪烁几次，重新起动，发动机起动后马上熄火。 故障原因：用红盒子SCANNER扫描仪读故障码，也可用手动来读取。诊断接头在发动机防火墙内，将自诊断输入端与信号回输端以跨线跨接，连接电压表，正极棒接蓄电池正极，负极棒接自诊输出端，当点火开关ON后，由电压表摆动的次数，即可读取故障码。清除故障码，则在点火开关ON后，正要显示故障码时，立即拆除跨接线即可，该车读出的故障码为进气温度传感器线路

12、不良。 故障排除：拆下进气温度传感器，测量其电阻，在不同温度下应有不同的阻值。 假如电阻正常，测量信号端电压源(即25号脚接线)，其电压应在5V左右。另外，当点火开关OFF时，46号共同搭铁线与车身搭铁的电阻应在5欧以下。检查结果，26号线开路，修好此线路，车辆恢复正常。 分析：进气温度传感器装在进气歧管上，或装在空气器滤芯旁边，用以检测进入气缸的空气温度，以修正喷油量，使空气燃油的混合比更适合于燃烧。它利用热敏电阻作感应，将不同的温度下电阻的变化，转变成信号电压。温度越高，信号电压越低，喷油量越少。 2、发动机暖机后怠速过低、不稳定故障检测与诊断分析 1）故障现象 发动机暖机后怠速运转时，转

13、速过低，容易熄火。 2）故障原因 点火正时过迟，气缸压缩力过低，喷油器性能差燃油泵工作状况不良。控制系统中曲轴位置传感器，发动机水温传感器不良。 3）诊断方法 用正时灯检查发动机点火正时；检查旁通进气管是否堵塞；检查节气门室气路是否堵塞；检查节气门是否卡阻；拔下调压器真空管，给调压器提供真空或加压，检查发动机怠速；调取故障码，利用输出代码。 发动机加速不良 1、维修实例： 车型：别克CENTURY牌轿车，装备V6电控发动机。 故障现象：行驶中加速不良，怠速时严重抖动，急加速时进气管回火。 故障分析与排除： 更换火花塞和汽油滤清汽器，清洗空气滤清器，故障依旧。用汽油喷射系统清洗剂及专用设备自动清

14、洗电喷装置清洗，仍无效果；拆下喷油器，清洗后故障仍旧。 拆下空气滤清器，用手赌住气门阀体的进口滤网，使主通道的进气面积减少，增加混合气浓度，结果怠速稳定，加速也不再回火，显然故障为混合气过稀所致。 测试燃油压力，启动发动机并改变转速，压力值在正常范围内。因空气流量传感器是影响空燃比的重要因素，拔下其插头，启动发动机，怠速稳定，加速性能也良好，故再检查空气流量传感器，接线未断，但线上有积垢。清除积垢并清洗后复原，故障排除。 2、发动机加速不良的故障检测与诊断分析 1）故障现象 加速时，发动机转速不易提高，或发动机“突突”响。 2）故障原因及检修 燃油系统：燃油管变形；检测燃油泵工作是否正常；检测

15、燃油燃油压力调节器和保持压力；检查喷油器的喷油量和密封性。 检查点火系统中火花塞和点火线圈是否损坏，点火正时是否失准。 电控系统：检查节流阀体；进气歧管转换阀；凸轮轴调节电磁阀；发动机电控单元；传感器状态。 检查ECU是否有故障。 机械系统：汽缸压力不正常；缸垫冲坏；空气滤清器堵塞，进气管路是否漏气；燃油质量不合格。 总结：上述为电控发动机常见故障，每一类故障又表现出不同的故障现象，并且各自有不同的故障原因。当发动机出现上述常见故障现象，又确定不了故障原因时，应找出每种故障可能的原因，逐一进行排除，直到最后确诊并修复。电控汽车故障分析与诊断应遵循“询问、查阅资料、直观检查、调取故障码、检测和试

16、验”检修过程和规律，采用逐一排除的方法，将确定故障的范围一步步缩小，最终找到故障部位。 随着汽车技术的不断发展，对汽车维修人员的要求也越来越高，汽车维修技术人员只有不断学习现代汽车技术相关知识和理论，更好的掌握汽车电子控制系统的保养，故障判断及排除方法，学会使用各种检测仪器设备，不断总结维修经验，提高维修技术水平，才能适应汽车维修技术日新月异的发展。 附件2：外文原文 Electronic Control Engine Troubleshooting Analysis Abstract: The variety of electronic control system and its cons

17、tant use 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 system during maintenance work common fault detection and diagnosis metho

18、ds of analysis and discussion. Key words: electronically controlled engine, maintenance, fault detection, diagnosis With the continuous development of the automotive industry, automobile manufacturing technology, electronic technology in the automotive application of increasingly wide. Electronic-co

19、ntrolled fuel injection 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 temperature, dust and other reasons, electronic-controll

20、ed fuel injection system will probably give rise to a variety of failures. Therefore, the master automotive electronic control system maintenance, fault detection and troubleshooting, to ensure the normal operation of motor vehicles is particularly important. First, the engine electronic control the

21、 composition and working principle Engine Electronic Control 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, the air quantity

22、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 injection, ignition and electronic components, such as idle speed control valve to control the obj

23、ect, to guarantee access to a variety of working conditions with the engine to match the best mixture components, fuel injection time and ignition time. Second, Electronic Control Engine Troubleshooting and Maintenance Methods Engine Electronic Control Fuel Injection System as long as there is oil h

24、as 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 or accelerated undesirable phenomenon, it is a more common fault, probably due to the f

25、uel 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 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: (

26、1) engine start-up difficulties 1, maintenance examples Models: Shanghai Passat B5 sedans. Fault phenomenon: hot car engine to start normally, and when cold, especially in the morning when starting the first time, start difficulties. Diagnosis and rule out the possibility: from fault symptoms analys

27、is, 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 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

28、 pressure gauge at this time the instructions on the value of approximately 400KP. Observed after 10min, the pressure is about 70KPa, note the system 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 v

29、alve leaking. (2) pipeline leak. External pipeline inspection without leakage, the analysis should be a one-way valve for the fuel leak, replace 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?

30、 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 replaced, troubleshooting. 2, engine start-up difficulties of fault detection and diagnosis analysis

31、 1) fault phenomenon Engine start-up difficulties, there 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 starter. 2) the cause of the malf

32、unction 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 lax. Ignition system failure: (1) intake air flow or pressure sensors, (2) Ne (speed signal) G1G2, (3) throttle position, temperature

33、sensors, (4) neutral NP (5) ignition module, (6) ignition coil primary, 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. 3) detection and diagnosis methods: (1) me

34、asuring 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 abnormal changes should be made, (4) the engine temperature sensor connector will be disconnected after the start-up engine, If normal, check the t

35、emperature sensor circuit and sensor, (5) to check whether the plug voltage regulator tube. (B) no engine fast idle 1, maintenance examples Vehicle: 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. Faul

36、t reasons: (1) check the throttle body wire harnesses, tape tied observation of whether any part of the damaged insulation. (2) electric wire harness 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 fa

37、ult 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 Detection and Diagnostic Analysis 1) fault phenomenon Start the engine and no fast idle. 2) the cause of the malfunction Ignition System: ignition timing inaccura

38、te. 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. 3) diagnostic methods (1) check the auxiliary air control valve work is normal and its circuit, (2) to check whether the plu

39、g-pass into the trachea, (3) check and adjust ignition timing, (4) Unplug the vacuum tube regulator 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 cir

40、cuit. (C) warm-up before the engine idle speed instability 1, repair examples: Vehicle: Toyota Crown 3.0 Fault phenomenon: after starting running cooler, the idle running unstable. Adjust idle speed screw, fault still exists. Fault Analysis and discharge: the car equipped with a diagnosis of electro

41、nic control devices. Available for their inspection 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 jack TE1 and E1. With a short wire to connect the two jacks, and

42、 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. Fault dashboard warning lights began flashing regularly 4 times and one times, that fault code 41. Check out the information that has throttle posit

43、ion sensor fault. Car throttle position sensor output for potentiometer-type structure, there are four posts, namely Vc (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 connec

44、tor, 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 elimination 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. Finall

45、y removed the diagnosis box on the wires can be short, the car throttle position sensor with the throttle while turning the potentiometer to change the variable resistor, the controller changes the voltage signal from that a throttle opening and position. If the throttle position sensor short circui

46、t or open circuit will cause the engine difficult to start, idle, or flame instability. 2, engine warm-up before the idle instability analysis of fault detection and diagnosis 1) fault phenomenon Start the engine running after the cooler, the idle running unstable. 2) the cause of the malfunction In

47、take System: (1) mixture concentration, auxiliary air control valve. Ignition System: ignition timing inaccurate. Control System: Engine water temperature sensor bad, EGR System: EGR control valve jammed shut down should not, EGR solenoid valve often broken. 3) diagnostic methods (1) the use of igni

48、tion 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 idle speed, if so, what changes, check the mixing ratio feedback system, (4) ex

49、haust gas recirculation control valve to check the status of work, (5) in the engine idling state examination EGR electromagnetic coil terminal voltage, (6) check throttle position sensor, (7) check the water temperature sensor and its circuit, (8) Unplug the engine temperature sensor connector afte

50、r 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 idling too low and unstable 1, maintenance examples Models: Ford Tianba VIN: 1FAPD36X5PH121840L42.3L, M / T Fault phenomenon: the car can start, start the

51、engine on the flame after 1min. In the flame flickering lantern engine several times before, re-start, engine start-up immediately after the flame. 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 se

52、lf-diagnosis input (ST1) 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 oscillating voltage meter, you can read the fault code. Clear

53、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 read out for the intake air temperature sensor circuit bad. Troubleshooting: Remove intake air temperature sensor, measuring its resistance, at different te

54、mperatures have different resistance. 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, when the ignition switch OFF, the 46 line and the body of common Ground Ground resistance should be below 5

55、in Europe. Inspection results, on the 26th line of open circuit, repair the lines, the vehicle returned to normal. 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 amen

56、d the fuel 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 voltage signal, the less amount of fuel injection. 2, the engine idle

57、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 In

58、jector (4) working conditions, bad fuel pump. Control system of the crankshaft position sensor, engine water temperature sensor bad. 3) diagnostic methods (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 thr

59、ottle plug (4) check whether the card throttle resistance, (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 (E) of the engine to accelerate the adverse 1, repair examples: Models: Buick CE

60、NTURY sedans equipped V6 engine electronic control. Fault phenomenon: moving to accelerate the poor idle when serious jitter, when the intake manifold backfire. Troubleshooting: Replacement of spark plugs and gasoline vapor filter, and clean air filter, fault still. Petrol injection system cleaning

61、agents and special equipment EFI automatic cleaning device cleaning, no effect; removed injector, fault remains after cleaning. Removed the air filter, hand gambling live import filter valve body so that the main channel to reduce the intake area, increasing the concentration of the mixture, resulti

62、ng in idle stability, not speed up the return fire, apparently as a mixture over fault Dilute due. 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 plug, start t

63、he 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, troubleshooting. 2, the engine speed up the bad fault detection and diagnosis analysis 1) fault phen

64、omenon Accelerate when the engine speed is not easy to raise, or the engine chug sound. 2) the cause of the malfunction and repair Fuel system: (1) fuel tube deformation, (2) testing the fuel pump work is normal, (3) testing the fuel pressure regulator fuel and maintain the pressure, (4) to check the fuel injec