7 Simple Changes That'll Make The Biggest Difference In Your Audi G28
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 on the outside of the transmission just above the flywheel gear. It sends a signal to the ECU via an uncolored wire (T55/49) which is then sent to the tachometer within the instrument cluster.
1. Engine Speed Sensor
The grey wire is located on the edge of transmission, just above the flywheel ring. The sensor transmits an electrical signal through the grey wire to pin T55/49. The ECU then utilizes this information to regulate the boost, fuel, and timig. It also sends an alert to the G5 Tachometer within the instrument cluster.
The sensor is used to link with the G40 Camshaft position Sensor. The ecu must know when the crankshaft is TDC and where the camshaft is so it can activate 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 are out of sync and possibly indicating chain stretch or a jumped link on the upper timing chain. However the code will not appear on its own, without additional information from other sensors (G4 and G40).
It's a bit 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 by measuring the resistance between the ECU and the sensor. It should read about 1000 ohms when the sensor is in full operation. If you're having issues with this sensor, look for signs of coolant or oil in the connector bay.
2. Injectors
Yesterday, when accelerating from highway paytoll at full speed I noticed a massive reduction in power. look at here now was as if the engine was running out of gas. Or my injectors were not firing. I pulled out the spark plugs this morning and found that 3 were soaked in gasoline, and the fourth was dry. When i crank the engine without sparks, I put a piece of tissue on top of each injector hole and the 3 that were drenched in gazoline leap out, however the 4th one stays closed. I inspected the ground connection on ECU pins 14/55,30/55 and 48/55 i get zero Ohm. I'm assuming that the issue is elsewhere.
I also tried to reset the PID without success. The car will start when the G28 is disconnected, but it is running fine with the G28 connected. However the intermittent misfire issue still occurs at higher RPM. The coolant temperature sensor (G62) shows the wrong temp value -49c even when i unplug it. I also noticed that the oil pressure gauge in the cockpit shows 2 bar while the actual pressure is 0.0 when i rev the engine.
I don't know what to do. I believe that I've ruled everything else out. I'm worried that i might have missed something. If anyone has suggestions, please chime in! TIA!
3. Fuel Pump
The fuel pump of the g28 receives signals from the RPM sensor. The GM-style transmitter is identical to the G4 sender and both work on the 80,100,200, UrS, and RS2 vehicles. You can easily find a spare in a wrecking shop or a parts store. It is simple to test them: simply switch your DMM into resistance mode and test the distance between pins 1 and 2 (with the bump on the connector's edge facing up). They must be infinite ohms.
4. ECU
The ECU in our 20vt turbo (3B AAN ABY) engines requires to know both the position and speed the crankshaft in order to make a decision about fuel injector timing, etc. To do this, it utilizes a Crank Position Sensor (G4) and an Engine Speed Sensor (G28). If either of these sensors go bad you will get codes on the diagnostic scanner which could cause engine shut down.
Some of the signs of a failing G28 sensor are an inaccurate gearbox rev counter the gears are shifting faster than normal, and/or a misfire when you are in gear. It is probable that the sensor is failing and needs to be replaced if you notice any of these symptoms. The good news is they are very affordable and easily accessible, especially if you're looking at a Bosch unit which is what we have. Alternately, the GM version of this unit is also a great option.
5. Tachometer
A faulty engine speed sensor could be the reason behind many problems in your vehicle. It's an essential component of your Audi's transmission, because it communicates to the ECU about how fast or slow the vehicle's crankshaft is turning. This sensor can cause the transmission to malfunction and other components in the car to be affected.
The G5 engine sensor is located at the edge of the transmission, just above the flywheel ring. It transmits signals via a gray wire to the ECU pin T55/49. The ECU utilizes this signal to control the amount of fuel and boost, and also timig. It also transmits it to the G5 Tachometer located in the instrument cluster. You can check the sensor for failure by examining the continuity between it and the tachometer, between the ECU pin T55/49 and the instrument cluster connection on pin T6a/1 (trace [79trace [79]) and between T6a/1 and the instrument cluster pin T26a/12. It should show approximately 1000 ohms of resistance between these two points. This is a common feature across the Audi 80-100-200-RS2 model, ranging from the 1985 MC all the way up to the 1997 UrS AN and the 1995 RS2 Du You may also find some good ones in wrecking yards.