5 Laws Anyone Working In Audi G28 Should Know
5 Laws Anyone Working In Audi G28 Should Know
Blog Article
How to Replace an Audi G28 Engine Speed Sensor
In this video Charles the Humble Mechanic demonstrates how to replace the G28 engine speed sensor. The sensor is situated on the edge of the transmission just above the flywheel ring gear. It transmits a signal to the ECU through the grey wire T55/49 and then to the tachometer on the instrument cluster.
1. Engine Speed Sensor
The grey wire is located on the edge of transmission, above the flywheel ring. This sensor sends a signal via the grey wire to pin T55/49. The ECU uses this information to control the amount of fuel and boost. It also sends an indicator to the G5 Tachometer located in the instrument cluster.
The sensor serves as a reference point to connect with the G40 Camshaft Position Sensor. The ecu needs to know when the crankshaft is TDC and where the camshaft is so it can trigger spark and injectors in the right way.
If this sensor fails to function, the ECU will display a P00160 error code. This indicates that the Crank Shaft is not in sync with the Intake Camshaft. It could also indicate the possibility of a chain stretch or jumped chain link in the upper timing chain. The code will not appear without the additional information provided by other sensors (G4 or G40).
It is a little tricky to test since there are several pins on the connector and each one has different functions. The most effective method to test it is by measuring the resistance between the ECU and the sensor. If the sensor is operational, it should be reading approximately 1000 ohms. Look for signs of coolant, or oil in the connector bay if you are experiencing issues with this part.
2. Injectors
Yesterday, when i was accelerating to the fullest speed from highway paytoll, i experienced massive power loss like the engine is running out of gas or injectors aren't firing any more. This morning i pull out the spark plugs, three were drenched in gazoline, the 4th one was dry. I put a piece of tissue over each injector hole and when i start the engine with no sparks, the 3 that have gazoline pop right out. The 4th one stays shut. I inspected the ground connection on ECU pins 14/55/30/55/48/55/14/55/48/ I got 0ohm. I assume that the problem is elsewhere.
I also tried to reset PID without success. The car is able to start if the G28 is not plugged in and runs fine when it is connected but it still is experiencing intermittent misfires at higher RPM. The coolant sensor (G62) even when it is unplugged, shows temperatures of -49c. Also i noticed that the gauge for oil pressure in the cockpit shows 2 bar, whereas the actual pressure is 0.0 when I crank up the engine.
I'm not sure what to do, but i feel i have pretty much ruled out everything else. But i'm worried that i might have missed something. If anyone has suggestions, please here let me know! TIA!
3. Fuel Pump
The fuel pump in the g28 is activated by a signal sent from the RPM sensor. The GM-style transmitter is the same as the G4 and both function in the 80, 100, 200, UrS and RS2 cars so you can easily find one at a junkyard or in a local parts store. It is simple to test them - simply switch your DMM new audi key into resistance mode and measure the distance between pins 1 and 2 (with the bump on the connector's edge facing audi keys replacement up). They must be infinite Ohms.
4. ECU
The ECU in our 20vt turbo (3B AAN ABY ADU) engines requires to know both the position and speed of the crankshaft to determine timing of fuel injectors, etc. It uses a Crank Position Sensor G4 and an Engine Speed Sensor G28 to achieve this. If either of these go badly, you will see codes on the diagnostic scanner which can lead to engine shutdown.
Some of the symptoms of a failed G28 sensor are an inaccurate gearbox rev counter the gears are shifting faster than normal and/or misfiring when you're in gear. If you experience any of these issues check here it is likely your sensor is deteriorating and needs replacing. They are cheap and easy-to-find, especially if they're a Bosch sensor like ours. If you prefer, GM's version of this component is an option.
5. Tachometer
A failing engine speed sensor could be the reason behind many issues with your car. It is an important part of the transmission in your Audi because it relays information to the ECU on how fast or slow the car's engine is turning. When this sensor fails, it can disrupt the performance of the transmission and the rest of the car's components.
The G5 engine sensor is located at the outskirts of the transmission, just above the flywheel ring. It transmits a signal via an uncolored wire to the ECU pin T55/49. The ECU then uses and processes this signal to regulate the flow of fuel, timig and boost and then sends it on to the G5 Tachometer located in the instrument cluster. You can check for sensor failure by checking continuity from the sensor to the tachometer. You can also verify continuity between pin T55/49 of the ECU and pin T6a/1 of the instrument cluster (trace [79]) and between pin T6a/1 and pin T26a/12. It should show approximately 1000 ohms of resistance between those two pins. This is a common part across the Audi 80, 100, 200, UrS and RS2 range from 1985 MC until the 1997 UrS AAN and 1995 RS2 ADU. Good ones might be availble in audi replacement key wrecking yards.