What Do You Think? Heck Is Audi G28?
What Do You Think? Heck Is 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 located on the outside of the transmission just above the flywheel 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 situated on the edge of transmission, just above the flywheel ring. The sensor transmits signals through the grey wire to pin T55/49. The ECU then uses this information to control fuel, timig and boost. It also sends an indication to the G5 Tachometer in instrument cluster.
The sensor is used as a reference point to connect with the G40 Camshaft Position Sensor. The ecu must be aware when the crankshaft is TDC and the location of the camshaft so it can activate 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 possibly indicating chain stretch or a jumped link on the upper timing chain. The code will not appear without the additional information supplied by other sensors (G4 or G40).
It can be a bit difficult to test as there are several connector pins, and each one has different functions. The best way to do it is to measure the resistance between the ECU and the sensor. When the sensor is operational, it should be reading about 1000 ohms. Check for signs of coolant, or oil in the connector bay if you are experiencing issues with this part.
2. Injectors
Yesterday, as i was accelerating off the highway paytoll at full speed I noticed a massive drop in power. It was as if the engine had run out of gas. Or, my injectors weren't firing. I pulled out the spark plugs this morning, three were drenched in gasoline and the 4th was dry. When I crank the engine without sparks, i place a tissue on the top of each hole in the injector and the 3 drenched with gazoline pop out, but the 4th stay shut. I checked the ground connection on ECU pins 14/55,30/55 and 48/55 I got zero ohm. So i assume the problem is in another place.
I also tried to reset the PID without success. The car can start if the G28 is disconnected and runs fine when it is connected, but still is experiencing intermittent misfires at higher RPM. The temperature sensor for the coolant (G62) shows the wrong temp value that is -49c even after unplugging 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 crank up the engine.
I'm not more info certain what to do, i think i've pretty much completely ruled out all other possibilities. I'm concerned that i may have missed something. If anyone has suggestions, please chime in! TIA!
3. Fuel Pump
The fuel pump in the g28 gets 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. It is easy to find an extra audi replacement car keys in a wrecking shop or parts store. It is easy to test them: simply switch your DMM into resistance mode and determine the distance between pins 1 and 2 (with the bump at the connector's end facing up). They must be infinite Ohms.
4. ECU
Our 20vt turbo (3B, AAN, ABY and ADU) engines have an ECU that has to be aware of the speed and position of the crankshaft in order to make a decision about timing of the fuel injector, for example. It uses a Crank Position Sensor G4 and an Engine Speed Sensor G28 to accomplish this. If either of these goes wrong, you will receive codes on the diagnostic scanner that could cause engine shut down.
A malfunctioning G28 sensor could cause an inaccurate speed counter for the gearbox and a gearbox which shifts more quickly than normal, and/or a misfire while in the gear. If you have any of these issues it is likely that your sensor is deteriorating and needs replacing. The good thing is that they are very affordable and easily accessible, especially when you're looking at a Bosch sensor, like ours. Alternatively, GM's version of this part is an option.
5. Tachometer
A malfunctioning engine sensor can cause a variety of issues within your vehicle. It's an essential component of your Audi's transmission, because it communicates to the ECU about how the car's crankshaft is turning. If the sensor fails, it could affect the performance of the transmission and the read more other car's components.
The G5 engine speed sensor is situated on the outside of the transmission, above the flywheel ring gear and sends a signal directly to the ECU at pin T55/49 via a grey wire. The ECU utilizes this signal to regulate the amount of fuel and boost, and also timig. It also relays it to the G5 Tachometer located in the instrument cluster. You can test for sensor failure by how much is a replacement audi key examining the continuity from the sensor to the tachometer. You can also verify continuity between pin T55/49 of the ECU and pin T6a/1 of the instrument cluster (trace [79]), and between pin T6a/1 as well as pin T26a/12. You should detect a resistance of approximately 1000 ohms in these areas. read more This is a common feature across the Audi 80-100-200-RS2 series, starting from the 1985 MC all the way up to the 1997 UrS An and 1995 RS2 Du, so you might find good ones in wrecking yards.