14 Smart Ways To Spend Extra Audi G28 Budget
14 Smart Ways To Spend Extra Audi G28 Budget
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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. The sensor is located at the top of the transmission, above the flywheel ring gear. It transmits a signal to the ECU via the grey wire (T55/49) which is then sent to the tachometer located in the instrument cluster.
1. Engine Speed Sensor
The grey wire is situated on the edge of transmission, just above the flywheel ring. The sensor sends a signal via the grey wire to pin T55/49. The ECU uses 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 for comparing with the G40 Camshaft Position Sensor. The ecu must know when the crankshaft is TDC and the location of the camshaft so it can start spark and injectors accordingly.
If this sensor fails, the ECU will throw a P00160 code which means the Crank Shaft and Intake Camshaft are out of sync and could indicate the chain is stretched or a jump link on the upper timing chain. However the code will not be displayed on its own without additional information from other sensors (G4 and G40).
Testing is a bit tricky since there are two connector pins and they serve different purposes however the best method to test it is to measure resistance between the sensor and the ECU. When the sensor is fully operational, it should read around 1000 ohms. Examine for signs of coolant, or oil in the connector bay if there are issues with this component.
2. Injectors
Yesterday accelerating full speed from highway paytoll, I experienced an abrupt drop in power as if the engine was running out of gas or the injectors aren't firing any more. I took out the spark plugs this morning, three were drenched in gasoline and the 4th was dry. When i crank the engine, there are no sparks, I put a piece of tissue on top of each injector hole, the 3 drenched with gazoline jump out but the 4th one stays closed. I tried to test the ground connections of ECU pins 14,30 and 48/55. I found 0ohm. I think the issue is in another location.
I also tried to reset the PID but with no luck. The car will start when the G28 is disconnected, but it runs fine with the G28 plugged in. However, the intermittent misfire problem continues to occur at higher RPM. The coolant sensor (G62), even when it is unplugged, shows a temperature of -49c. Also, i noticed that the oil pressure gauge in the cockpit shows 2 bar when the actual pressure is 0.0 when I crank up the engine.
I'm not sure what to do, but i feel i have pretty much ruled out everything else. However, i'm afraid that I might have missed something. If anyone has suggestions, please share them! TIA!
3. Fuel Pump
The fuel pump on the g28 is activated by a signal from the RPM sensor. The GM-style transmitter is similar to the G4 sender and works on the 80,100,200, UrS, and RS2 vehicles. You can easily find a spare in a wrecking shop or parts store. It is easy to test them - just put your DMM into resistance mode and determine the distance between pins 1 and get more info 2 (with the bump at the connector end facing upwards). They should be infinite Ohms.
4. ECU
The ECU of our 20vt turbo (3B AAN ABY) engines must be aware of the position and speed of the crankshaft in order to make a decision about timing of fuel injectors, etc. It uses a Crank Position Sensor G4 and an Engine Speed Sensor G28 to accomplish this. If you are experiencing issues with either of these, the diagnostic scanner will show codes that could lead to an engine shut down.
A damaged G28 sensor could cause an inaccurate speed counter for the gearbox or a gearbox that shifts faster than normal, or an unfire when in gear. It is possible that the sensor is failing more info and needs more info to be replaced if you experience any of these signs. The good thing is that they are quite affordable and easy to find particularly if you're looking at a Bosch sensor, which is what ours get more info are. If you prefer, GM's version of this part is a good option.
5. Tachometer
A damaged engine sensor could cause a myriad of issues in your vehicle. It's a vital component of your Audi's transmission, since it relays information to the ECU about how the car's crankshaft is rotating. This sensor can cause the transmission to malfunction and other car components to be affected.
The G5 engine sensor is located at the outskirts more info of the transmission, just above the flywheel ring. It sends an electrical signal through an uncolored wire to the ECU pin T55/49. The ECU is then able to process this signal to regulate the flow of fuel, timig and boost as well as sends it on to the G5 tachometer inside the instrument cluster. You can test the sensor for failure by examining the continuity between it and the tachometer, between the ECU pin T55/49 and the instrument cluster connection to pin T6a/1 (trace [79]) as well as between T6a/1, and the instrument cluster pin T26a/12. You should observe around 1000 ohms of resistance between these two points. This is a common part that is found across the Audi 80, 100 200, UrS and RS2 range from 1985 MC to the 1997 UrS AAN and 1995 RS2 ADU, so the best ones might be availble in wrecking yards.