Japan Vehicles Diagnostics

aauto from California in iATN message писал(а):... Any help will be appreciated. Car came in with cylinder misfires on bank #1. Feels like a lean misfire. According to short and long trim bank one runs rich. When disconnecting battery to reset fuel trim and running engine with disconnected MAF engine runs better. Upon running the engine and disconnecting injectors one by one at bank #1 it shows power contribution much less than doing the same procedure on bank #2. Can not find a reason for this issue. Thanks in advance.
:New information: After disconnecting all AFR and 02 sensors and driving it car runs great. It is obvious now that the ECM commands lean due to AFR sensor reading rich. Disconnecting battery overnight does not bring the AFR voltage to 3.3 as I suspected. Now im not sure that should happen. So the question to you guys. Is the AFR supposed to reset to 3.3V after disconnecting battery? If yes then ECM is defective because on this ECM bank 1 shows 1.9v and bank 2 shows 3.3. So is the ECM defective or am i missing something else? What else can make the AFR voltage low (rich mixture) with lean condition for bank 1 only. We double checked AFR, O2 sensors and there heaters. Camshaft timing checked and compression checked. Will appreciate and input on this issue.
Thanks, here is a link to the scanner data screenshots
https://drive.google.com/drive/folders/ ... sp=sharing

Компрессия не выявит подгоревшие клапана,а такие случаи бывали

VVA писал(а):... Вибрация ощущается, misfires не отображается. Но 2UZ-FE 98 г.в.

alflash писал(а):... PCV или форсунки или EVAP или что?

• - MAF,
  - форсунки,
  - свечи,
  - O2S,
  - ECM,
  - проводка.
  - регулятор давления топлива (в баке),
  - VVT-i
  ...

• - PCV*,
  - EVAP,
  ...

• - катушек (их перестановкой),
  - напряжения на "опорном" контакте AFRS B1S1(проверка 3.0V вольтметром)****,
  - катализатора (проверкой давления на такте "выпуск" или хотя бы манометром)**

VVA писал(а):Вот это "сюжет" с финалом!

VVA писал(а):Жду , в понед-вторн 2UZ с "вибрацией", на хх. В прошлый раз (2мес назад)разобраться не смог и не оч актуально было, были друг. деф.
Но и вибрация , не оч. заметная.. Пропусков нет.

VVA писал(а):... Даже неисправный ЭБУ , по идее можно увидеть осциллом. Что-то ведь должно быть "не так".

• а) неисправность проявлялась через "плавание" напряжения на O2S B1S1, которое не соответствовало реальному составу смеси,
  б) напряжение на O2S B1S1 было отлично видно в Data Stream и полностью соответствовало проверке с помощью вольтметра,

alflash писал(а):.. И я не исключаю, что это не окончательный финал этой беспрецедентной истории ...

MONITOR DESCRIPTION.
The ECM uses the two sensors, mounted in front of and behind the Three−way Catalytic Converter (TWC), to monitor its efficiency.
The first sensor, the Air−Fuel Ratio (A/F) sensor (sensor 1), sends pre−catalyst information to the ECM. The second sensor, the Heated Oxygen (HO2) sensor (sensor 2), sends post−catalyst information to the ECM.
The ECM compares the information transmitted by these two sensors to determine the efficiency of the TWC performance and its ability to store oxygen.
When the TWC is functioning properly, the variation in the oxygen concentration in the exhaust gas, after it has passed through the TWC, is small. In this condition, the voltage output of sensor 2 slowly alternates between the rich and lean signal voltages. As the TWC performance efficiency deteriorates, its oxygen storage capacity decreases, and the variation in the oxygen concentration in the exhaust gas increases. As a result, the sensor voltage output fluctuates frequently.
While the catalyst monitor is running, the ECM measures the signal lengths of both sensors 1 and 2, and calculates the ratio of the signal lengths to determine the extent of the TWC deterioration. If the deterioration level exceeds the preset threshold, the ECM interprets this as the TWC malfunction. The ECM then illuminates the MIL and sets the DTC.
DTC Detecting Condition: OSC value smaller than standard value under (self) active air−fuel ratio control* (2 trip detection logic) ...
HINT:
Malfunctioning areas can be identified by performing the A/F CONTROL function provided in the ACTIVE TEST. The A/F CONTROL function can help to determine whether the Air−Fuel Ratio (A/F) sensor, Heated Oxygen (HO2) sensor and other potential trouble areas are malfunctioning.

A/F Control