Audi G28: The Ugly Truth About Audi G28
Audi G28: The Ugly Truth About Audi G28
Blog Article
How to Replace an Audi G28 Engine Speed Sensor
Charles the Humble Technician shows how to replace the G28 Engine Speed Sensor. This sensor is situated near the transmission's edge over the flywheel gear. It sends a message to the ECU via a grey wire T55/49, then to the tachometer on the instrument cluster.
1. Engine Speed Sensor
Located on the edge of the transmission just above the flywheel ring gear G28 Engine Speed Sensor sends signals to ECU pin T55/49 via an uncolored wire. The ECU then uses this information to control the flow of fuel, timig and boost. It also sends an indication to the G5 tachometer in the instrument cluster.
The sensor serves as a reference to correlate with the G40 Camshaft Position Sensor. The ecu must know when the crankshaft is TDC and where the camshaft is located so that it can start spark and injectors according to the situation.
If this sensor fails, the ECU will display an error code P00160 which indicates that the Crank Shaft and Intake Camshaft are out of sync and possibly indicating chain stretch or a jumped link on the upper timing chain. The code won't show without the additional information provided by other sensors (G4 or G40).
It can be a bit difficult to test as there are different connector pins, and each has its own functions. The most effective method to test it is by measuring the resistance between the ECU and the sensor. When the sensor is operational, it should be reading approximately 1000 ohms. Examine for signs of coolant, or oil in the connector bay if there are issues with this component.
2. Injectors
Yesterday, while accelerating from the highway paytoll at full speed, i noticed a huge decrease in power. It was like the engine was running out of gas. Or my injectors weren't firing. I pulled out the spark plugs this morning and found that 3 were soaked in gasoline, and the fourth was unclean. I put tissue over each hole in the injector and when i start the engine without sparks, the 3 with gazoline jump out. The fourth one remains closed. I checked the ground connection of ECU pins 14,30 and 48/55. I found 0ohm. I'm assuming that the issue is elsewhere.
I also tried to reset the PID but without success. The car will start when the G28 is unplugged, and it is running fine with the G28 connected. However, the intermittent misfire problem still occurs at higher RPM. The coolant sensor (G62), even when it is unplugged, shows temperatures of -49c. I also noticed that the oil gauge in the cockpit shows 2 bars while the website actual pressure is zero.
I'm not sure what to do. I feel like i've pretty much eliminated everything else. But i am afraid I might have missed something. If anyone has any suggestions, please share them! TIA!
3. Fuel Pump
The fuel pump in the g28 receives a signal from the RPM sensor. The GM-style transmitter is identical to the G4 sender and works on the 80,100,200, UrS, and RS2 vehicles. You can easily locate the spare in a salvage shop or parts store. It is easy to test them website - just switch your DMM into resistance mode and determine the distance between pins 1 and 2 (with the bump on the connector's edge facing up). They should be infinite Ohms.
4. ECU
Our 20vt turbo (3B AAN, ABY and ADU) engines are equipped with an ECU that has to know the speed and position of the crankshaft to make decisions about fuel injector timing etc. It uses a Crank Position audi tt keys Sensor G4 and an Engine Speed Sensor G28 to accomplish this. If either of these sensors go bad you will get codes on the diagnostic scanner which can cause the engine to shut down.
The signs of a failed G28 sensor include an inaccurate rev counter for the gearbox, gears shifting quicker than normal and/or misfiring when you are in gear. It is possible that the sensor is failing and needs to be replaced if you notice any of these signs. The good news is they are quite affordable and easily accessible particularly if you're looking at an Bosch model, like ours. Alternatively, the GM version of this part is also a great option.
5. Tachometer
A malfunctioning engine sensor can cause a variety of issues in your vehicle. It's an essential component of your Audi's transmission, as it sends information to the ECU about how fast or slow the car's crankshaft is spinning. If this sensor fails, it can affect the performance of the transmission and the rest of the car's components.
The G5 engine sensor is located at the edge of the transmission, just above the flywheel ring. It transmits a signal via an uncolored wire to the ECU pin T55/49. The ECU is then able to process the signal to control fuel, timig, and boost as well as sends it on to the G5 tachometer inside the instrument cluster. You can determine if the sensor is in failure by examining the continuity website from the sensor to the tachometer. Also, you can examine the continuity between pins T55/49 of the ECU and pin T6a/1 of the instrument cluster (trace [79]) and between pin T6a/1 as well as pin T26a/12. There should be the resistance to be around 1000 ohms between these points. This is a typical part 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 audi a4 spare key wrecking yards.