This Is The Ugly Truth About Audi G28
This Is The Ugly Truth About Audi G28
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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 on the edge of the transmission above the flywheel ring gear. It sends a signal to the ECU via an uncolored wire (T55/49) which is then sent to the tachometer in the instrument cluster.
1. Engine Speed Sensor
The grey wire is situated on the edge of transmission, above the flywheel ring. The sensor transmits a signal via the grey wire to pin T55/49. The ECU then uses this information to control the flow of fuel, timig and boost. It also sends an alert to the G5 Tachometer in instrument cluster.
The sensor serves as a reference point to connect with the G40 Camshaft Position Sensor. The ecu has to know when the crankshaft reached TDC, and the position of the camshaft, to trigger the spark and injectors.
If this sensor fails to function, the ECU will display an error code P00160. This indicates that the Crank Shaft is out of alignment with the Intake Camshaft. It could also be a sign of the possibility of a chain stretch or jumped chain link in the upper timing chain. The code won't appear without the additional information provided by other sensors (G4 or G40).
Testing is a bit challenging since there are two connector pins and they have different functions however the best method to test it is to measure the resistance between the sensor and the ECU. It should read around 1000 ohms when it is operating at its maximum. If you are having problems with this part, check for evidence of oil or coolant in the connector bay.
2. Injectors
Yesterday, while accelerating from the highway paytoll at a high speed, i noticed a huge reduction in power. It was as if the engine had run out of gas. Or, my injectors were not firing. I took out the spark plugs this morning, 3 were soaked in gasoline, and the 4th was dry. When I crank the engine with no sparks, i place a tissue on top of each injector hole, the 3 drenched with gazoline pop out, but the 4th stays shut. I inspected the ground connection on ECU pins 14/55, 30/55 and 48/55. I got zero Ohm. So i assume the problem is somewhere else.
I also tried to reset PID without success. The car will start when the G28 is disconnected, but it runs fine with the G28 connected. However the intermittent misfire issue persists at higher RPM. The coolant sensor (G62), even when unplugged, still shows an ice temperature of -49c. I also noticed that the oil gauge in the cockpit shows 2 bar when the actual pressure is 0.
I'm not certain what to do, but i feel i have pretty much completely ruled out all other possibilities. However, i'm afraid that i might have missed something. Let me know If you have any suggestions! TIA!
3. Fuel Pump
The fuel pump on the g28 is activated by a signal by the RPM sensor. The GM-style transmitter is similar to the G4 sender and both work 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 - just put your DMM into resistance mode and test the distance between pins 1 and 2 (with the bump at the connector end facing up). They must be infinite Ohms.
4. ECU
Our 20vt turbo (3B AAN, ABY and ADU) engines have an ECU that has to be aware more info of the speed and position of the crankshaft in order to make a decision about timing of the fuel injector, for example. To do this, it utilizes a Crank Position Sensor (G4) and an Engine Speed Sensor (G28). If you have a problem with either of these sensors, the diagnostic scanner will display codes that could lead to the engine shutting down.
A malfunctioning G28 sensor can cause an inaccurate speed counter for the gearbox and a gearbox which shifts more quickly than normal, and/or an unfire when in gear. audi a1 keys If you experience any of these problems, it is likely that your sensor is deteriorating and needs replacing. The good thing is that they are very affordable and easily accessible, especially in the case of a Bosch model, which is what ours are. Alternately, the GM version of this unit is also a great option.
5. Tachometer
A malfunctioning engine sensor can cause a variety of issues in your car. check here It's an website essential component of the transmission in your Audi, as it transmits information to the ECU regarding how fast or slowly the car's engine is turning. If the sensor fails, it can affect the performance of the transmission, as well as the other car's components.
The G5 engine sensor is located near the edge of check here the transmission, over the flywheel ring. It transmits a signal via a gray wire to the ECU pin T55/49. The ECU uses this signal to regulate the amount of fuel and boost, and also to timigrate. It also sends it to the G5 Tachometer in instrument cluster. You can test the sensor for failure by checking continuity between it and the tachometer, between ECU pin T55/49 and the instrument cluster connection via pin T6a/1 (trace [79]) and between pin T6a/1 and the instrument cluster pin T26a/12. You should see approximately 1000 ohms of resistance between those points. This is a standard part that is found across the Audi 80, 100, 200, UrS and RS2 range from 1985 MC through the 1997 UrS AAN and 1995 RS2 ADU. Good ones could be available in wrecking yards.