"Ask Me Anything": Ten Answers To Your Questions About Audi G28
"Ask Me Anything": Ten Answers To Your Questions 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 near the edges of the transmission, above the flywheel ring gear. It transmits a signal the ECU via a grey wire (T55/49) and then to the tachometer located in the instrument cluster.
1. Engine Speed Sensor
The grey wire is situated on the outside of the 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 boost, fuel, and timig. It also sends a signal to the G5 tachometer in the instrument cluster.
The sensor is used to correlate with the G40 Camshaft position Sensor. The ecu must be aware when the crankshaft is TDC and where the camshaft is located so that it can trigger spark and injectors accordingly.
If this sensor fails the ECU will throw the P00160 error, which means the Crank Shaft and Intake Camshaft aren't in sync and possibly indicating the chain stretching or a jump link on 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 various pins on the connector, and they all have different functions. The most effective method to test it is to measure the resistance between the ECU and the sensor. When the sensor is functional, it should read about 1000 ohms. If you're experiencing issues with this part, check for evidence of coolant or oil in the connector bay.
2. Injectors
Yesterday, when accelerating from highway paytoll at maximum speed, i noticed a huge reduction 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, 3 were drenched in gasoline and the fourth was unclean. I put a piece of tissue over each hole in the injector and when i start the engine without sparks, the ones with gazoline jump right out. The 4th one remains shut. I inspected the ground connection on ECU pins 14/55,30/55 and 48/55 i get 0ohm. Therefore, i think the issue is somewhere else.
I also tried to reset PID but without success. The car is able to start when the G28 is disconnected and is running fine when it is connected but it still has intermittent misfire issues 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 bar but the actual pressure is 0.
I'm not sure what to do, as i think i've pretty much ruled out everything else. But i am afraid I may have missed something. If anyone has any suggestions, please chime in! TIA!
3. Fuel Pump
The fuel pump on the g28 is activated by a signal from the RPM sensor. The GM-style sensor is identical to the G4 and both function in the 80, 100, 200, UrS and RS2 cars which is why you can easily locate one at a salvage yard or in a local parts store. It is easy to test them - just switch your DMM into resistance mode and test the distance between pins 1 and 2 (with the bump at the connector's end facing upwards). They must be infinite Ohms.
4. ECU
The ECU in our 20vt turbo (3B AAN ABY ADU) engines must know the position and speed the crankshaft in order to make a decision about timing of fuel injectors, etc. It utilizes a Crank Position Sensor G4 and an Engine Speed Sensor G28 to accomplish this. If either of these goes wrong, you will receive codes on the diagnostic scanner which can lead to engine shutdown.
The signs of a malfunctioning G28 sensor include an inaccurate gearbox rev counter, gears shifting quicker than normal and/or a misfire when website in gear. If you have any of these issues it is likely your sensor is going bad and needs replacing. They're cheap and easy to find particularly when they're a Bosch model like ours. You can also choose the GM version of this unit is also a great option.
5. Tachometer
A failing engine sensor could cause a myriad of issues in your car. It's a vital component of your Audi's transmission, since it relays information to the ECU about how the car's crankshaft is spinning. When this sensor fails, it will affect the performance of the transmission and the other car's components.
The G5 check here engine speed sensor is located at the edge of the transmission just above the flywheel ring gear and sends a signal to the ECU at pin T55/49 through a grey wire. The ECU utilizes this signal to control the flow of fuel and boost as well as timig. It also transmits more info it to the G5 Tachometer located 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 check here T55/49 and the instrument cluster connection to pin T6a/1 (trace [79trace [79]) and between T6a/1 and the instrument cluster pin check here T26a/12. You should detect a resistance of approximately 1000 ohms between these points. This is the same across the Audi 80-100-200-RS2 range, from the 1985 MC up to the 1997 UrS An and 1995 RS2 DU You may also find them in wrecking yards.