20 Myths About Audi G28: Dispelled
20 Myths About Audi G28: Dispelled
Blog Article
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 near the transmission's edge over the flywheel gear. It transmits a signal to the ECU via an uncolored wire (T55/49) and then to the tachometer in the instrument cluster.
1. Engine Speed Sensor
The grey wire is situated 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 utilizes this information to control fuel and boost. It also sends an alert to the G5 Tachometer in instrument cluster.
The sensor is used as a reference for comparing with the G40 Camshaft Position Sensor. The ecu needs to know when the crankshaft is TDC and where the camshaft is so it can trigger spark and injectors accordingly.
If this sensor fails the ECU will display an error code P00160 which indicates that the Crank Shaft and Intake Camshaft are out of sync and could indicate the chain stretching or a jump link on 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 is a bit tricky because there are two connector pins, and they have different functions however the best method to test it is to measure resistance between the sensor and the ECU. It should read around 1000 ohms when it is operating at its maximum. Check for evidence of coolant or oil in the connector bay if you have issues with this part.
2. Injectors
Yesterday, as i was accelerating off the highway paytoll at full speed I noticed a significant drop in power. It was as if the engine was running out of gas. Or my injectors weren't firing. I pulled out the spark plugs this morning, three were soaked with gasoline and the 4th was dry. When I start the engine, there are no sparks, I put a piece of tissue on the top of each hole in the injector, the 3 drenched with gazoline jump out but the 4th stay closed. I checked the ground connection of ECU pins 14,30 and 48/55. I found 0ohm. Therefore, i think the issue is in another place.
I also tried to reset the PID without success. The car will start when the G28 is disconnected, but it runs fine with the G28 plugged in. However, here the intermittent misfire problem continues to occur 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 is showing 2 bar when the actual pressure is 0.0 when I crank up the engine.
I'm not sure what to do. I think I've ruled everything else out. But i'm worried that I might have missed something. If anyone has any ideas please let me know! TIA!
3. Fuel Pump
The fuel pump in the g28 receives signals from the RPM sensor. The GM-style sender is identical to the G4 and both function in the 80, 100 200, UrS and RS2 cars so you can easily find one at a junkyard or from a parts store. It is simple to test them - put your DMM in resistance mode and measure between pins 1 (with the bump on the connector end up) and 2 (2nd from the left on the black connector's end). They must be infinite Ohms.
4. ECU
The ECU of our 20vt turbo (3B AAN ABY) engines requires to know the position and speed of the crankshaft to determine fuel injector timing, etc. In order to do this it uses a Crank Position Sensor (G4) and an Engine Speed Sensor (G28). If you are experiencing here issues with either one of these, the diagnostic scanner will display codes that could cause an engine shutdown.
The signs of a failing G28 sensor are an inaccurate gearbox rev counter and gears that click here shift faster than normal, and/or a misfire when you're in gear. If you experience any of these issues it is most likely that your sensor is failing and should be replaced. They are cheap and easy-to-find especially when they're a Bosch sensor like ours. Alternatively, GM's version of this part is a good option.
5. Tachometer
A malfunctioning engine sensor can cause a number of problems within your vehicle. It's an essential component get more info of the Audi's transmission as it sends information to the ECU about how the car's crankshaft is spinning. If this sensor fails, it will affect the performance of the transmission and the other car's components.
The G5 engine speed sensor is located at the edge of the transmission above the flywheel ring gear and sends a signal to the ECU at pin T55/49 via an uncolored wire. The ECU uses this signal to control fuel and boost, and also to timigrate. It also sends it to the G5 Tachometer in instrument cluster. You can check for sensor failure by examining the continuity of the sensor to the tachometer. Additionally, you can verify continuity between pin T55/49 of the ECU and pin T6a/1 of the instrument cluster (trace [79trace [79]), and between pin T6a/1 and pin T26a/12. It should show approximately 1000 ohms of resistance between those two pins. This is a standard part across the check here Audi 80, 100, 200, UrS and RS2 range from 1985 MC until the 1997 UrS AAN and 1995 RS2 ADU so good parts could be found in wrecking yards.