7 Simple Changes That'll Make The Difference With Your Audi G28
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 situated on the outside of the transmission just above the flywheel gear. It transmits a signal to the ECU via the grey wire (T55/49) and then to the tachometer within the instrument cluster.
1. Engine Speed Sensor
The sensor is located at the edge of the transmission above the flywheel ring gear the G28 Engine Speed Sensor sends an electrical signal to ECU pin T55/49 via a grey wire. The ECU uses this information to regulate boost and fuel. It also sends signals to the G5 tachometer inside the instrument cluster.
The sensor is used as a reference point to connect with the G40 Camshaft Position Sensor. The ecu must know when the crankshaft reached TDC and also the position of the camshaft, to trigger the spark and injectors.
If this sensor fails when it fails, the ECU will display an error code P00160. This means that the Crank Shaft is not in alignment with the Intake Camshaft. It could also be a sign of a chain stretch or a jumped chain link in the upper chain of timing. However, the error code won't appear on its own without additional information from other sensors (G4 and G40).
Testing can be a bit difficult because there are two pins for the connector and they serve different purposes but the best method to test it is by measuring resistance between the sensor and the ECU. It should read approximately 1000 ohms when the sensor is at full operation. Look for signs of coolant or oil in the connector bay if you have issues with this part.
2. Injectors
Yesterday, while accelerating at full speed from the highway paytoll, I experienced an abrupt drop in power like the engine is running out of gas or injectors are not firing anymore. This morning i pull out the spark plugs, 3 were drenched with gazoline the 4th one was dry. When i crank the engine with no sparks i put tissue on the top of each hole in the injector, the 3 drenched with gazoline jump out but the 4th one stays shut. I checked the ground connection of ECU pins 14,30 and 48/55. I found 0ohm. I assume that the problem is elsewhere.
I also tried to reset the PID without success. The car will start if the G28 is disconnected and it runs perfectly when it is plugged in but it still has the intermittent misfire issue at higher RPM. The coolant sensor (G62), even if it is not plugged in, shows temperatures of -49c. I also noticed that the oil gauge in the cockpit shows 2 bars when the actual pressure is 0.
I'm not certain what to do, as i think i've pretty much ruled out everything else. But i'm worried that I might have missed something. If anyone has any suggestions, please let me know! TIA!
3. Fuel Pump
The fuel pump in the g28 receives signals from the RPM sensor. The GM-style sensor is identical to 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 wrecking yard or at a parts store. Test them out by putting your DMM in resistance mode and measure the resistance between pins 1 (with the bump on the connector's end up) and 2 (2nd from the left on the black connector's side). They should be infinite ohms.
4. ECU
Our 20vt turbo (3B AAN, ABY and ADU) engines are equipped with an ECU that has to know the position and speed of the crankshaft in order to make a decision about timing of the fuel injector, for example. To do this, it utilizes a Crank Position Sensor (G4) and an Engine Speed Sensor (G28). If you encounter a problem with either one of these, the diagnostic scanner will display codes that could lead to an engine shut down.
A malfunctioning G28 sensor can cause an inaccurate speed counter for your gearbox, a gearbox that shifts faster than normal, and/or an unfire when in the gear. It is probable that your sensor is failing and needs to be replaced if you experience any of these symptoms. audi key replacement near me are cheap and easy-to-find especially in the case of an Bosch unit like ours. You can also choose the GM version of this unit is also a good option.
5. Tachometer
A faulty engine speed sensor could be the reason behind numerous problems in your vehicle. 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. This sensor could cause the transmission to fail and other components in the car to be affected.
The G5 engine speed sensor is located on the edge of the transmission just above the flywheel ring gear. It sends a signal to the ECU at pin T55/49, via a grey wire. The ECU uses this signal to regulate the amount of fuel and boost, as well as timig. It also relays it to the G5 Tachometer in instrument cluster. You can check for sensor failure by examining the continuity of the sensor to the tachometer. You can also check 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. You should see the resistance to be around 1000 ohms between these points. This is a common feature across the Audi 80-100-200-RS2 range, from the 1985 MC all the way up to the 1997 UrS AN and the 1995 RS2 Du, so you might find some good ones in wrecking yards.