Many Of The Most Exciting Things Happening With Audi G28
Many Of The Most Exciting Things Happening With Audi G28
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How to Replace an Audi G28 Engine Speed Sensor
In this video, Charles the Humble Mechanic shows how to replace the G28 engine speed sensor. The sensor is located at the top of the transmission, above the flywheel ring gear. It sends a message to the ECU via a grey wire T55/49, then to the tachometer located on the instrument cluster.
1. Engine Speed Sensor
The grey wire is located on the outside of the transmission, above the flywheel ring. This sensor sends an electrical signal through the grey wire to pin T55/49. The ECU utilizes this information to control fuel and boost. It also sends a signal to the G5 tachometer inside the instrument cluster.
The sensor is used to link with the G40 Camshaft position Sensor. The ecu needs to know when the crankshaft is TDC and where the camshaft is located so that it can trigger spark and injectors in the right way.
If this sensor fails the ECU will throw an error code P00160 which indicates that the Crank Shaft and Intake Camshaft aren't in 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).
Testing can be a bit difficult because there are two connector pins and they perform different functions however the best method to test it is to measure resistance between the sensor and the ECU. It should read about 1000 ohms when it is in full operation. If you're experiencing issues with this component, look 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 experienced massive power loss like the engine is running out of gas or the injectors are not firing at all. Today, i pulled out the spark plugs. Three were soaked with gazoline and the fourth one was dry. I put tissue over each injector hole and when i start the engine without sparks, the three with gazoline jump out. The fourth one remains closed. I tested the ground connection on ECU pins 14/55, 30/55 and 48/55. I get zero ohm. I assume that the problem is somewhere else.
I also tried to reset PID without success. The car is able to start when the G28 is disconnected and is running fine when it is connected however it has intermittent misfire issues at higher RPM. The temperature sensor for coolant (G62) shows the wrong temp value that is -49c even after unplugging it. I also noticed that the oil pressure gauge in the cockpit is showing 2 bar when the actual pressure is 0.0 when i rev the engine.
I'm not sure what to do. I feel like i've pretty much eliminated everything else. I'm afraid i may have missed something. Please let me know If you have any suggestions! TIA!
3. Fuel Pump
The fuel pump of the g28 receives a signal from the RPM sensor. The GM-style transmitter 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 wrecking yard or in a local parts store. It is easy to test them: simply 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) more info engines are equipped with an ECU that needs to be aware of the speed and position of the crankshaft to make a decision about timing of the fuel injectors, etc. To accomplish this, it utilizes a Crank Position Sensor (G4) and an Engine Speed Sensor (G28). If either of these goes badly, you will see codes on the diagnostic scanner which can cause the engine to shut down.
Some of the signs of a malfunctioning G28 sensor are an inaccurate rev counter in the gearbox the audi replacement key gears are shifting faster than normal and/or misfiring when in gear. It is likely that your sensor is failing and requires to be replaced if you notice any of these signs. The good news is they are very cheap and easy to find, especially if you're looking at a Bosch unit which is what ours are. Alternatively, GM's version of this part would be a good option.
5. Tachometer
A faulty engine speed sensor could here be the cause of a slew of issues with your car. It's a vital component of the Audi's transmission as it sends information to the ECU about how fast or slow the car's crankshaft is rotating. If the sensor fails, it will cause problems for the transmission as well as the rest of the car's components.
The G5 engine speed sensor is situated on the outside of the transmission, above the flywheel new audi key ring gear. It sends a signal to the ECU at pin T55/49 through a grey wire. The ECU uses this signal to control the flow of fuel and boost as well as timig. It also sends it 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, between the ECU pin T55/49 and the instrument cluster connection on pin T6a/1 (trace [79]) and between pin T6a/1 and the instrument cluster pin T26a/12. You more info should observe approximately 1000 ohms resistance between those points. This is a common feature across the Audi 80-100-200-RS2 range, from the 1985 MC up to the 1997 UrS AN and the 1995 RS2 DU, so you might find some good ones in wrecking yards.