The 10 Most Scariest Things About Audi G28
The 10 Most Scariest Things About Audi G28
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How to Replace an Audi G28 Engine Speed Sensor
Charles the Humble Technician shows you how to replace the G28 Engine Speed Sensor. The sensor is situated on the edge of the transmission above the flywheel ring gear. It sends a message to the ECU through the grey wire T55/49 and then to the tachometer in the instrument cluster.
1. Engine Speed Sensor
The grey wire is located at the edges of the transmission, just above the flywheel ring. The sensor transmits a signal via the grey wire to pin T55/49. The ECU utilizes this information to control fuel and boost. It also sends signals 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 must know when the crankshaft reached TDC, and the location of the camshaft in order to activate 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 line with the Intake Camshaft. It could also indicate the possibility of a chain stretch or jumpy chain link in the upper chain. The code won't show without the additional information supplied by other sensors (G4 or G40).
Testing is a bit challenging as there are two different pins for the connector and they perform different functions but the most effective method of testing it is to measure resistance between the sensor and the ECU. It should read around 1000 ohms when it is operating at its maximum. If you're experiencing issues with this component, look for signs of coolant or oil in the connector bay.
2. Injectors
Yesterday accelerating full speed from highway paytoll, I experienced an abrupt drop in power like the engine is out of gas or the injectors aren't firing any more. I took out the spark plugs this morning and found that 3 were soaked in gasoline, and the 4th was dry. I put tissue over each injector hole, and when i start the engine without sparks, the 3 with gazoline jump right out. The 4th one stays shut. I tried to test the ground connections of ECU pins 14,30, and 48/55. I found 0ohm. I assume that the problem is in another location.
I also tried to reset the PID but with no luck. The car can start if the G28 is disconnected and is running fine when it is plugged in, but still has the intermittent misfire issue at higher here 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 bars while the actual pressure is zero.
I'm not sure what to do, as i think i've pretty much completely ruled out all other website possibilities. But i am afraid I might have missed something. If anyone has any suggestions, please let me know! TIA!
3. Fuel Pump
The fuel pump in the g28 is activated by a signal from the RPM sensor. The check here GM-style transmitter is identical to the G4 sender and works on the 80,100,200, UrS, and RS2 vehicles. It is easy to find the spare in a salvage shop or a parts store. Test them out - put your DMM in resistance mode and measure between pins 1 (with the bump on the more info connector end up) and 2 (2nd from the left on the black end of the connector). They should be infinite Ohms.
4. ECU
Our 20vt turbo (3B AAN, ABY and ADU) engines are equipped with an ECU that must be aware of the speed and position of the crankshaft in order to make decisions regarding timing of the fuel injectors, etc. To do this, it uses a Crank Position Sensor (G4) and an Engine Speed Sensor (G28). If either of these sensors go wrong, you will receive codes on the diagnostic scanner that could cause engine shut down.
The signs of a failed G28 sensor include an inaccurate rev counter in the gearbox, gears shifting quicker than normal and/or a misfire when you are in gear. If you experience any of these issues, it is likely your sensor is failing and should be replaced. They're cheap and easy to find, especially if they're a Bosch unit like ours. Alternatively, the GM version of this unit is also a great option.
5. Tachometer
A malfunctioning engine sensor can cause a number of problems in your vehicle. It is an important part of the transmission of your Audi since it sends information to the ECU on how fast or slow the engine is turning. If this sensor fails, it can disrupt the performance of the transmission, as well as the other car's components.
The G5 engine sensor is located at the edge of transmission, above the flywheel ring. It transmits a signal via gray wire to ECU pin T55/49. The ECU is then able to process this signal to control fuel, timig, and boost as well as transmitting it to the G5 tachometer in the instrument cluster. You can test the sensor for any failure by checking the continuity between it and the tachometer, between the ECU pin T55/49 and the instrument cluster connection to pin T6a/1 (trace how to open audi car key [79trace [79]) and between T6a/1 and the instrument cluster pin T26a/12. It should show approximately 1000 ohms of resistance between those two pins. This is a standard component across the Audi 80 100, 200, UrS and RS2 range from 1985 MC to the 1997 UrS AAN and 1995 RS2 ADU, so the best parts could be found in wrecking yards.