How to Replace an Audi G28 Engine Speed Sensor
Charles the Humble Technician shows how to replace the G28 Engine Speed Sensor. This sensor is located at the edge of transmission just above the flywheel 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 situated on the outside of the transmission, directly above the flywheel ring. The sensor sends a signal via the grey wire to pin T55/49. The ECU then utilizes this information to regulate the boost, fuel, and timig. It also sends an indication to the G5 Tachometer located in the instrument cluster.
The sensor serves as a reference for comparing with the G40 Camshaft Position Sensor. The ecu must be aware when the crankshaft is TDC and where the camshaft is so it can activate spark and injectors accordingly.
If this sensor fails when it fails, 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 chain. The code will not appear without the additional information provided by other sensors (G4 or G40).
It is a little tricky to test as there are several pins on the connector and each has its own functions. The most effective method to test it is by measuring the resistance between the ECU and the sensor. When the sensor is operational, 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 i was accelerating to the fullest speed from highway paytoll, I experienced an abrupt drop in power like the engine is running out of gas or injectors are not firing at all. I pulled out the spark plugs this morning and found that 3 were soaked with 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 three with gazoline jump right out. The 4th one stays closed. I checked the ground connection on ECU pins 14/55, 30/55 and 48/55. I got zero Ohm. So i assume the problem is in another place.
I also tried to reset the PID without success. The car can start when the G28 is not plugged in and it runs perfectly when it is plugged in however it has the intermittent misfire issue at higher RPM. The temperature sensor for the coolant (G62) shows the wrong temp value -49c even when i unplug it. I also noticed that the gauge for oil pressure in the cockpit shows 2 bar when the actual pressure is 0.0 when i rev the engine.
I'm not sure what to do, but i believe that i've eliminated everything else. I'm worried that i might have missed something. Please let me know should you have any suggestions! TIA!
3. Fuel Pump
The fuel pump in the g28 is activated by a signal by the RPM sensor. The GM-style transmitter is the same as the G4 and they both work in the 80, 100, 200, UrS and RS2 cars which is why you can easily locate one at a junkyard or from a parts store. It is simple to test them - simply put your DMM into resistance mode and determine the distance between pins 1 and 2 (with the bump at the connector's end facing upwards). They must be infinite Ohms.
4. ECU
Our 20vt turbo (3B AAN, ABY and ADU) engines are equipped with an ECU that needs to know the speed and position of the crankshaft in order to make decisions regarding timing of the fuel injectors, etc. It makes use of a Crank Position Sensor G4 and an Engine Speed Sensor G28 to accomplish this. If you have a problem with either of these, the diagnostic scanner will display codes that could cause an engine shutdown.
A damaged G28 sensor could cause an inaccurate speed counter for your gearbox and a gearbox which shifts more quickly than normal, and/or an unfire when in gear. It is possible that your sensor is failing and needs to be replaced if you experience any of these symptoms. They're cheap and easy to find particularly in the case of an Bosch model like ours. Alternately, GM's version this component is an option.
5. Tachometer
A failing engine sensor could cause a number of problems in your car. It's an essential component of the Audi's transmission since it relays information to the ECU about how the car's crankshaft is rotating. If this sensor fails, it will cause problems for the transmission, as well as the other car's components.
The G5 engine sensor is located near the edge of the transmission, just above the flywheel ring. It sends a signal via a gray wire to the ECU pin T55/49. The ECU uses this signal to control the amount of fuel and boost, and also timig. It also sends it to the G5 Tachometer located in the instrument cluster. You can test the sensor for failure by examining the continuity between it and the tachometer, between ECU pin T55/49 and the instrument cluster connection on pin T6a/1 (trace [79trace [79]) and between pin T6a/1 and the instrument cluster pin T26a/12. You should see approximately 1000 ohms of resistance between those two pins. simply click the up coming article is a common feature across the Audi 80-100-200-RS2 range, beginning with the 1985 MC and up to the 1997 UrS AN and 1995 RS2 Du, so you might find good ones in wrecking yards.