Audi G28: The Good, The Bad, And The Ugly
Audi G28: The Good, The Bad, And The Ugly
Blog Article
How to Replace an Audi G28 Engine Speed Sensor
In this video Charles the Humble Mechanic shows how to replace the G28 engine speed sensor. This sensor is located near the edges of the transmission above the flywheel ring gear. It transmits a signal to the ECU via the grey wire T55/49 and then to the tachometer located on the instrument cluster.
1. Engine Speed Sensor
It is located on the outside of the transmission just above the flywheel ring gear the G28 Engine Speed Sensor sends a signal to ECU pin T55/49 through the grey wire. The ECU then uses this information to control the boost, fuel, and timig. It also sends an alert to the G5 Tachometer located in the instrument cluster.
The sensor is used to link the G40 Camshaft position Sensor. The ecu needs to know when the crankshaft is TDC and where the camshaft is located so that it can trigger spark and injectors in the right way.
If this sensor fails the ECU will display an error code P00160 which indicates that the Crank Shaft and Intake Camshaft are not in sync and could indicate the chain is stretched or a jump link on the upper chain of timing. The code won't appear without the additional information provided by other sensors (G4 or G40).
It can be a bit difficult to test as there are several pins on the connector and they all have different functions. The best way to do it is to measure the resistance between the ECU and the sensor. It should read approximately 1000 ohms if the sensor is operating at its maximum. Check for signs of coolant, or oil in the connector bay if you are experiencing issues with this part.
2. Injectors
Yesterday, while accelerating at full speed from the highway paytoll i had an abrupt drop in power like the engine is running out of gas or the injectors are not firing at all. Today, i pulled out the spark plugs. Three were drenched with gazoline the fourth one was dry. I put a piece of tissue over each injector hole, and when i start the engine without sparks, the ones with gazoline jump right out. The fourth one remains closed. I tested the ground connection of ECU pins 14,30, and 48/55. I got zero ohm. So i assume the problem is somewhere else.
I also tried to reset the PID but without success. The car will start when the G28 is unplugged, and it is running fine with the G28 plugged in. However, the intermittent misfire problem still occurs at higher RPM. The coolant sensor (G62) even when unplugged, still shows temperatures of -49c. Also i noticed that the gauge for oil pressure in the cockpit is showing 2 bar, whereas the actual pressure is 0.0 if i crank up the engine.
I'm not sure what to do. I believe that I've eliminated everything else. I'm concerned that i may have missed something. Please let me know should you have any suggestions! TIA!
3. Fuel Pump
The fuel pump of the g28 gets a signal from the RPM sensor. The GM-style sender is the same as the G4 and both function in the 80, 100, 200, UrS and RS2 cars which is why you can easily locate one at a wrecking yard or from a parts store. It is simple to test them: simply switch your DMM into resistance mode and test the distance between pins 1 and 2 (with the bump at the connector end facing upwards). They should be infinite Ohms.
4. ECU
The ECU in our 20vt turbo (3B AAN ABY) engines must be aware of the position and speed the crankshaft to make decisions regarding 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 sensors, the diagnostic scanner will show the codes that could trigger the engine shutting down.
A damaged G28 sensor can cause an inaccurate speed counter for your gearbox or a gearbox that shifts faster than normal, or a misfire while in the gear. It is probable that your sensor is failing and needs to be replaced if you experience any of these signs. The audi car keys good news is they are quite affordable and easy to find particularly if you're looking at an Bosch model, which is what we have. Alternatively, the GM version of this component is also a good option.
5. Tachometer
A failing engine sensor could cause a number of problems in your car. It's a crucial component of the transmission of your Audi, as it transmits information to the ECU about how fast or slow the engine is spinning. If this sensor fails, it will disrupt the performance of the transmission more info as well as the other car's components.
The G5 engine sensor is located near the edge read more of the transmission, over the flywheel ring. It sends a signal via gray wire to ECU pin T55/49. The ECU then processes this signal to control fuel, timig, and boost and then sends it on to the G5 audi key replacement tachometer in the instrument cluster. You can test the sensor for failure by checking continuity between it and the tachometer, between ECU pin T55/49 and the instrument cluster connection on pin T6a/1 (trace [79]) and between pin T6a/1 and the instrument cluster pin T26a/12. You should see around 1000 ohms of resistance between those points. This part is common across the Audi 80-100-200-RS2 model, ranging from the 1985 MC up more info to the 1997 UrS An and 1995 RS2 Du You may also find good ones in wrecking yards.