10 Quick Tips About 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 located on the outside of the transmission, above the flywheel gear. It transmits a signal to the ECU through a grey wire T55/49, then to the tachometer located on the instrument cluster.
1. Engine Speed Sensor
The grey wire is located at the edges of the transmission, just above the flywheel ring. The sensor transmits signals through the grey wire to pin T55/49. The ECU utilizes this information to regulate boost and fuel. It also sends a signal to the G5 Tachometer located in the instrument cluster.
The sensor serves as a reference to correlate with the G40 Camshaft Position Sensor. The ecu must know when the crankshaft is TDC and where the camshaft is so it can start spark and injectors in the right way.
If this sensor fails, the ECU will display a P00160 error message. This indicates that the Crank Shaft is out of sync with the Intake Camshaft. It could also be a sign of the possibility of a chain stretch or jumpy chain link in the upper chain of timing. The code won't show without the additional information provided by other sensors (G4 or G40).
spare audi key cost can be a bit difficult to test because there are several connector pins, and they all have different functions. The most effective method to test it is to measure the resistance between the ECU and the sensor. When the sensor is operational, it should read approximately 1000 ohms. If you're having issues with this sensor, look for signs of oil or coolant in the connector bay.
2. Injectors
Yesterday accelerating full speed from highway paytoll i had an abrupt drop in power as if the engine was running out of gas or 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. When I crank the engine with no sparks, I put a piece of tissue on the top of each of the injector holes, the 3 drenched with gazoline leap out, however the 4th one stays shut. I inspected the ground connection on ECU pins 14/55, 30/55 and 48/55. I get zero ohm. Therefore, i think the issue is elsewhere.
I also tried to reset the PID without success. The car will start when the G28 is unplugged, and it runs fine with the G28 plugged in. However, the intermittent misfire problem continues to occur at higher RPM. The temperature sensor for the coolant (G62) shows the wrong temp value -49c, even if I unplug it. I also noticed that the gauge for oil pressure in the cockpit shows 2 bar, whereas the actual pressure is 0.0 when I crank up the engine.
I'm not certain what to do, as i feel i have pretty much eliminated everything else. However, i'm afraid that I might have missed something. If anyone has any suggestions, please chime in! TIA!
3. Fuel Pump
The fuel pump in the g28 can be activated by a signal by the RPM sensor. The GM-style transmitter is similar to the G4 sender, and both operate on the 80,100,200, UrS, and RS2 vehicles. It is easy to find the spare in a salvage shop or parts store. It is simple to test them - just switch your DMM into resistance mode and measure 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 have an ECU that must know the speed and position of the crankshaft in order to make decisions regarding fuel injector timing etc. To do this, it uses a Crank Position Sensor (G4) and an Engine Speed Sensor (G28). If you are experiencing issues with either of these, the diagnostic scanner will display codes that could lead to the engine shutting down.
A malfunctioning G28 sensor could cause an inaccurate speed counter for your gearbox or a gearbox that shifts more quickly than normal, or an unfire when in gear. If you are experiencing any of these issues it is most likely that your sensor is deteriorating and requires replacement. They're inexpensive and easy to locate especially if they're an Bosch model like ours. Alternately, the GM version of this component is also a good option.
5. Tachometer
A malfunctioning engine speed sensor could be the cause of many issues in your vehicle. It's an essential component of the Audi's transmission as it sends information to the ECU about how fast or slow the car's crankshaft is spinning. If the sensor fails, it can cause problems for the transmission and the rest of the car's components.
The G5 engine sensor is located at the outskirts of the transmission, over the flywheel ring. It transmits signals via an uncolored wire to the ECU pin T55/49. The ECU is then able to process the signal to control the flow of fuel, timig and boost and then transmitting it to the G5 tachometer in the instrument cluster. You can test for sensor failure by checking continuity from the sensor to the tachometer. Additionally, you can examine the continuity between pins T55/49 of the ECU and pin T6a/1 of the instrument cluster (trace [79]) and between pin T6a/1 as well as pin T26a/12. You should observe around 1000 ohms of resistance between those points. This part is common across the Audi 80-100-200-RS2 series, starting from the 1985 MC all the way up to the 1997 UrS AN and 1995 RS2 DU, so you might find good ones in wrecking yards.