Audi G28 10 Things I'd Love To Have Known In The Past
Audi G28 10 Things I'd Love To Have Known In The Past
Blog Article
How to Replace an Audi G28 Engine Speed Sensor
Charles the Humble Technician teaches how to replace the G28 Engine Speed Sensor. This sensor is located on the outside of the transmission over the flywheel gear. It transmits a signal to the ECU through the grey wire T55/49 and then to the tachometer in the instrument cluster.
1. Engine Speed Sensor
Located on the edge of the transmission above the flywheel ring gear the G28 Engine Speed Sensor sends signals to ECU pin T55/49 using an uncolored wire. The ECU then utilizes this information to regulate the flow of fuel, timig and boost. It also sends an indication to the G5 Tachometer located in the instrument cluster.
The sensor is used to correlate with the G40 Camshaft position Sensor. The ecu has to be aware of when the crankshaft has reached TDC and also where the camshaft lies to trigger the spark and injectors.
If this sensor fails, the ECU will throw the P00160 error, which means the Crank Shaft and Intake Camshaft are not in sync, possibly indicating chain stretch or a jumped link on the upper chain of timing. However the code will not be displayed on its own without additional information from other sensors (G4 and G40).
It can be a bit difficult to test since there are different connector pins, and each one has different functions. The best method for doing this is to measure the resistance between the ECU and the sensor. It should read around 1000 ohms if the sensor is at full operation. Look for signs of coolant or oil in the connector bay if you have issues with this component.
2. Injectors
Yesterday, when i was accelerating to the fullest speed from highway paytoll, I experienced a big cut in power as if the engine was running out of gas or injectors aren't firing at all. In the morning, i removed the spark plugs. Three were drenched with gazoline the fourth was dry. I put a piece of tissue over each hole in the injector and when i start the engine with no sparks, the 3 that have gazoline pop right out. The fourth one remains shut. I tested the ground connection on ECU pins 14/55, 30/55 and 48/55. I get 0ohm. I think the issue is somewhere else.
I also tried to reset the PID but with no luck. The car will start when the G28 is disconnected, but it is running fine with the G28 audi replacement car keys plugged in. However, the intermittent misfire problem continues to occur at higher RPM. The temperature sensor website for coolant (G62) shows the wrong temperature of -49c even when i unplug it. I also noticed that the oil gauge in the cockpit shows 2 bar but the actual pressure is zero.
I'm not sure what to do. I feel like i've pretty much ruled everything else out. But i'm worried that I may have missed something. If anyone has suggestions, please share them! TIA!
3. Fuel Pump
The fuel pump on the g28 here is activated by a signal from the RPM sensor. The GM-style transmitter is similar to the G4 sender and both work on the 80,100,200, UrS, and RS2 vehicles. You can easily locate an extra in a wrecking shop or parts store. Test them out to do - just put your DMM in resistance mode and measure between pins 1 (with the bump on the connector's end up) and 2 replacement key for audi a4 (2nd from the left on the black end of the connector). They must be infinite Ohms.
4. ECU
Our 20vt turbo (3B AAN, ABY and ADU) engines have an ECU that must know the position and speed of the crankshaft to make a decision about fuel injector timing etc. In order to do this it utilizes a Crank Position Sensor (G4) and an Engine Speed Sensor (G28). If either of these goes wrong, you will receive codes on the diagnostic scanner which can lead to engine shutdown.
Some of the signs of a malfunctioning G28 sensor include an inaccurate rev counter in the gearbox, gears shifting quicker than normal and/or misfiring when you're in gear. It is probable that your sensor is failing and needs to be replaced if you encounter any of these signs. They're cheap and easy to find especially when they're a Bosch model like ours. Alternately, the GM version of this component is also a good choice.
5. Tachometer
A failing engine sensor could cause a number of problems within your vehicle. It's an essential component of the Audi's transmission since it relays information to the ECU about how the car's crankshaft is rotating. This sensor could cause the transmission to malfunction and other components of the car to be affected.
The G5 engine speed sensor is situated on the edge of the transmission above the flywheel ring gear and sends a signal to the ECU at pin T55/49 through an uncolored wire. 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 inside the instrument cluster. You can check for sensor failure by examining the continuity of the sensor to the tachometer. Also, you can examine the continuity between pins here T55/49 of the ECU and pin T6a/1 of the instrument cluster (trace [79]), and between pin T6a/1 and pin T26a/12. You should observe around 1000 ohms of resistance between these two points. This is a common feature across the Audi 80-100-200-RS2 model, ranging beginning with the 1985 MC and up to the 1997 UrS An and 1995 RS2 DU You may also find some good ones in wrecking yards.