The 10 Most Scariest Things About Audi G28
The 10 Most Scariest Things About Audi G28
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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 situated at the top of the transmission, above the flywheel ring gear. It transmits a signal to the ECU through the grey wire T55/49 and then to the tachometer located on the instrument cluster.
1. Engine Speed Sensor
The grey wire is located on the outside of the transmission, 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 signals to the G5 Tachometer located in the instrument cluster.
The sensor is used as a reference for comparing with the G40 Camshaft Position Sensor. The ecu must be aware of when the crankshaft has reached TDC and also the position of the camshaft, so that it can activate the spark and injectors.
If this sensor fails the ECU will show a P00160 code which means the Crank Shaft and Intake Camshaft aren't in sync and could indicate the chain stretching or a jump link on the upper timing chain. However, the error code won't appear on its own without additional information from other sensors (G4 and G40).
Testing is a bit challenging since there are two pins for the connector and they have different functions however the best method of testing it is to measure resistance between the sensor and the ECU. It should read around 1000 ohms when the sensor is in full operation. Look for evidence of coolant or oil in the connector bay if you have problems with this part.
2. Injectors
Yesterday, while accelerating at full speed from the highway paytoll, I experienced massive power loss like the engine is running out of gas or the injectors aren't firing any more. This morning i pull out the spark plugs, three were soaked with gazoline and the 4th one was dry. I put tissue over each hole in the injector and when i turn the engine on without sparks, the three with gazoline jump out. The fourth one remains shut. I tested the ground connection of ECU pins 14,30, and 48/55. I got 0ohm. I'm assuming that the issue is elsewhere.
I also tried to reset the PID with no success. The car will start when the G28 is disconnected, but audi a1 key it works fine when the G28 connected. However, the intermittent misfire problem continues to occur at higher RPM. The temperature sensor for coolant (G62) shows the wrong temp value -49c even when i unplug it. Also, i noticed that the oil pressure gauge in the cockpit is showing 2 bar when the actual pressure is 0.0 when i rev the engine.
I'm not sure what to do, as i think i've pretty much ruled out everything else. However, i'm afraid that i might have missed something. Please let me know if you have any ideas! TIA!
3. Fuel Pump
The fuel pump in the g28 receives a signal from the RPM sensor. The GM-style sensor is identical to the G4 and both are used 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 by putting your DMM in resistance mode and take measurements between pins 1 (with the bump on the connector end up) and 2 (2nd from the left on the black end of the connector). They should be infinite Ohms.
4. ECU
The ECU in our 20vt turbo (3B AAN ABY ADU) engines requires to know the position and speed the crankshaft to make decisions regarding timing of fuel injectors, etc. 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 shutdown.
Some of the signs of a malfunctioning G28 sensor are an inaccurate gearbox rev counter and gears that shift faster than normal, and/or a misfire when you're in gear. It is possible that the sensor is failing and needs to be replaced if you notice any of these signs. They're cheap and easy to find, especially if read more they're a Bosch sensor like ours. Alternately, GM's version this part is an excellent choice.
5. Tachometer
A malfunctioning engine sensor can cause a myriad of issues within your vehicle. It's an essential component of the Audi's transmission since it relays information to the ECU about how fast or slow the vehicle's crankshaft is rotating. If the sensor fails, it will affect the performance of the transmission as well as the rest of the car's components.
The G5 engine speed sensor is situated on the edge of the transmission above the get more info flywheel ring gear. It sends a signal directly to the ECU at pin T55/49 through get more info a grey wire. The ECU uses this signal to regulate the amount of fuel and boost, as well as timig. It also transmits it to the G5 Tachometer in instrument cluster. You can check for sensor failure by examining the continuity from the sensor to the tachometer. You can also 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 more info well as pin T26a/12. You should see approximately 1000 ohms of resistance between those points. This part is common across the Audi 80-100-200-RS2 range, from the 1985 MC all the way up to the 1997 UrS An and 1995 RS2 DU You may also find them in wrecking yards.