How To Outsmart Your Boss On Audi G28
How To Outsmart Your Boss On Audi G28
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. This sensor is located at the edge of transmission over the flywheel gear. It transmits a signal to the ECU via a grey wire (T55/49), then to the tachometer within the instrument cluster.
1. Engine Speed Sensor
The sensor is located at the edge of the transmission just above the flywheel ring gear, the G28 Engine Speed Sensor sends signals to ECU pin T55/49 through the grey wire. The ECU then utilizes this information to regulate the boost, fuel, and timig. It also sends a signal to the G5 Tachometer located in the instrument cluster.
The sensor is used as a reference point to connect with the G40 Camshaft Position Sensor. The ecu must know when the crankshaft is TDC and the location of the camshaft so it can trigger spark and injectors accordingly.
If this sensor fails the ECU will throw a P00160 code which means the Crank Shaft and Intake Camshaft are not in sync and possibly indicating the chain is stretched or a jump link on the upper timing chain. However, the error code won't appear on its own without additional information from other sensors (G4 and G40).
Testing is a bit tricky because there are two connector pins, and they have different functions but the best way to test it is by measuring resistance between the sensor and the ECU. When the sensor is fully functional, it should read around 1000 ohms. If you're having issues with this part, check for signs of coolant or oil in the connector bay.
2. Injectors
Yesterday, when i was accelerating to the fullest speed from highway paytoll i had an abrupt drop in power like the engine is running out of gas or injectors aren't firing any more. I pulled out the spark plugs this morning, three were drenched in gasoline and the 4th was dry. I placed a tissue over each hole in the injector and when i start the engine without sparks, the 3 that have gazoline pop right out. The fourth one remains shut. I inspected the ground connection on ECU pins 14/55,30/55 and 48/55 i get 0ohm. I'm assuming the issue is in another place.
I also tried to reset PID without success. The car will start if the G28 is unplugged and runs fine when it is plugged in but it still is experiencing intermittent misfires at higher RPM. The coolant sensor (G62), even when unplugged, still shows a temperature of -49c. I also noticed that the oil gauge in the cockpit shows 2 bar when the actual pressure is zero.
I'm not sure get more info what to click here do, as i feel i have pretty much completely ruled out all other possibilities. But i am afraid i might have missed something. If anyone has any suggestions, please share them! TIA!
3. Fuel Pump
The fuel pump of the g28 receives a signal from the RPM sensor. The GM-style sender is the same as the G4 and both are used in the 80, 100, 200, UrS and RS2 cars which is why you can easily locate one at a junkyard or from a parts store. It is easy to test them: simply put your DMM into resistance mode and test the distance between pins 1 and here 2 (with the bump on the connector's edge facing upwards). They must be infinite Ohms.
4. ECU
The ECU in our 20vt turbo (3B AAN ABY) engines needs to know the position and speed the crankshaft to make decisions regarding timing of the fuel injector, etc. It utilizes 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 that can cause the engine to shut down.
The signs of a failing G28 here sensor are an inaccurate rev counter for the gearbox the gears are shifting faster than normal, and/or a misfire when you're in gear. It is likely that the sensor is failing and needs to be replaced if you encounter any of these signs. They're inexpensive and easy to locate, especially if they're a Bosch model like ours. You can also choose the GM version of this component is also a great option.
5. Tachometer
A failing engine speed sensor could be the cause of a slew of problems in your car. It's a crucial component of the transmission of your Audi because it relays information to the ECU on how fast or slowly the engine is turning. This sensor could cause the transmission to malfunction and other components of the car to be affected.
The G5 engine speed sensor is located at the outside of the transmission just above the flywheel ring gear and sends a signal to the ECU at pin T55/49, via a grey wire. The ECU then uses and processes this signal to control fuel, timig and boost, and also sends it on to the G5 tachometer inside the instrument cluster. You can check the sensor for any failure by checking the continuity between it and the tachometer. You can also check continuity between ECU pin T55/49 and the instrument cluster connection on pin audi a4 spare key T6a/1 (trace [79trace [79]) and between T6a/1 and the instrument cluster pin T26a/12. You should detect a resistance of approximately 1000 ohms between these points. This is a typical component across the Audi 80 100 200, UrS and RS2 range from 1985 MC until the 1997 UrS AAN and 1995 RS2 ADU, so the best ones might be availble in wrecking yards.