Why The Biggest "Myths" About Audi G28 Could Actually Be True
Why The Biggest "Myths" About Audi G28 Could Actually Be True
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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. This sensor is situated on the outside of the transmission just above the flywheel gear. It sends a message to the ECU through a grey wire T55/49, then to the tachometer on the instrument cluster.
1. Engine Speed Sensor
The grey wire is located on the edge of transmission, just above the flywheel ring. The sensor sends an electrical signal through the grey wire to pin T55/49. The ECU then uses this information to control fuel, timig and boost. It also sends an indication to the G5 Tachometer in instrument cluster.
The sensor serves as a reference to correlate 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 according to the situation.
If this sensor fails, the ECU will show an error code P00160 which indicates that the Crank Shaft and Intake Camshaft are not in sync and possibly indicating the chain is stretched or a jump link on the upper timing chain. However, the error code won't appear on its own without additional information from other sensors (G4 and G40).
Testing is a bit tricky as there are two different connector pins, and they serve different purposes but the most effective method to test it is to measure the resistance between the sensor and the ECU. It should read approximately 1000 ohms if the sensor is at full operation. If you are having problems with this part, check for evidence of coolant or oil in the connector bay.
2. Injectors
Yesterday accelerating full speed from highway paytoll, I experienced massive power loss like the engine is out of gas or the injectors are not firing at all. This morning i pull out the spark plugs, three were soaked with gazoline and the 4th one was dry. I put tissue over each injector hole and when I turn the engine on without sparks, the three with gazoline jump right out. The 4th one stays closed. I tested the ground connection on ECU pins 14/55, 30/55 and 48/55. I get zero ohm. So i assume the problem is elsewhere.
I also tried to reset the PID without success. The car will start when the G28 is disconnected, but it works fine when the G28 connected. However the intermittent misfire issue 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 bar when the actual pressure is 0.
I'm not certain what to do, but i believe that i've eliminated everything else. I'm afraid i may have missed something. Please let me know if you have any ideas! TIA!
3. Fuel Pump
The fuel pump in the g28 is activated by a signal by the RPM sensor. The GM-style sensor is identical to the G4 and both are used in the 80, 100 200, UrS and RS2 cars which is why you can easily locate one at a junkyard or at a 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 end facing up). They should be infinite Ohms.
4. ECU
Our 20vt more info turbo (3B AAN, ABY and ADU) engines have an ECU that must know the speed and position of the crankshaft to make decisions regarding timing of the fuel injector, for example. It utilizes a Crank Position Sensor G4 and an Engine Speed Sensor G28 to achieve this. If either of these go wrong, you will receive codes on the diagnostic scanner that can cause the engine to shut down.
Some of the symptoms of a failed G28 sensor are an inaccurate rev counter for the gearbox check here and gears click here that shift faster than normal and/or misfiring when you are in gear. If you experience any of these problems, it is most likely that your sensor is failing and should be replaced. They are cheap audi spare key and easy-to-find particularly if they're a Bosch sensor like ours. You can also choose the GM version of this part is also a great option.
5. Tachometer
A malfunctioning engine sensor can cause a myriad of issues in your car. It is an important part of the transmission in your Audi because it relays information to the ECU regarding how fast or slow the engine of the car is spinning. When this sensor fails, it can cause problems for the transmission, as well as the other car's components.
The G5 engine speed sensor is situated on the outside of the transmission, above the flywheel ring gear. It here sends a signal to the ECU at pin T55/49 through a grey wire. The ECU uses this signal to control the amount of fuel and boost, and also timig. It also transmits it to the G5 Tachometer in instrument cluster. You can test for sensor failure by examining the continuity of the sensor to the tachometer. Additionally, you can verify continuity between pin T55/49 of the ECU and pin T6a/1 of the instrument cluster (trace [79trace [79]) and between pin T6a/1 as well as pin T26a/12. It should show around 1000 ohms of resistance between those two pins. This part is common 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 some good ones in wrecking yards.