Why You Should Concentrate On Making Improvements To Audi G28
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 near the edges of the transmission, above the flywheel ring gear. It sends a message to the ECU through the grey wire T55/49 and then to the tachometer in the instrument cluster.
1. Engine Speed Sensor
The grey wire is situated at the edges of the transmission, above the flywheel ring. The sensor transmits an electrical signal through the grey wire to pin T55/49. The ECU utilizes this information to regulate the amount of fuel and boost. It also sends an indication to the G5 tachometer in the instrument cluster.
advanced key audi serves as a reference to correlate with the G40 Camshaft Position Sensor. The ecu has to know when the crankshaft reached TDC, and the position of the camshaft, to trigger the spark and injectors.
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 possibly indicating the chain is stretched or a jump link on the upper chain of timing. The code will not appear without the additional information supplied by other sensors (G4 or G40).
Testing is a bit challenging because there are two pins for the connector and they serve different purposes however the best way to test it is to measure resistance between the sensor and the ECU. When the sensor is operational, it should read around 1000 ohms. If you are having problems with this sensor, look for evidence of coolant or oil in the connector bay.
2. Injectors
Yesterday, when accelerating from 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. Today, i pulled out the spark plugs, 3 were drenched in gazoline, the fourth one was dry. I put tissue over each injector hole and when i turn the engine on without sparks, the ones with gazoline jump right out. The 4th one stays shut. I tried to test the ground connections of ECU pins 14,30, and 48/55. I found zero ohm. Therefore, i think audi a1 key is in another place.
I also tried to reset the PID but without success. The car can start when the G28 is unplugged and runs fine when it is connected however it has the intermittent misfire issue at higher RPM. The coolant temperature sensor (G62) shows the wrong temperature value of -49c even when i unplug it. Also, i noticed that the oil pressure gauge in the cockpit shows 2 bar while the actual pressure is 0.0 when i rev the engine.
I'm not certain what to do, i feel i have pretty much ruled out everything else. I'm worried that i might have missed something. If anyone has suggestions, please share them! TIA!
3. Fuel Pump
The fuel pump of the g28 gets a signal from the RPM sensor. The GM-style sender is identical to the G4 and they both work in the 80 100 200, UrS and RS2 cars which is why you can easily locate one at a junkyard or at a parts store. It is simple to test them - simply switch your DMM into resistance mode and determine the distance between pins 1 and 2 (with the bump on the connector's edge facing upwards). They must be infinite Ohms.
4. ECU
The ECU in our 20vt turbo (3B AAN ABY ADU) engines requires to know both the position and speed the crankshaft in order to make a decision about timing of fuel injectors, etc. To accomplish this, it utilizes a Crank Position Sensor (G4) and an Engine Speed Sensor (G28). If you are experiencing issues with either of these sensors, the diagnostic scanner will display the codes that could trigger an engine shut down.
Some of the signs of a failed G28 sensor are an inaccurate rev counter in the gearbox, gears shifting quicker than normal, and/or a misfire when you are in gear. If you are experiencing any of these issues it is likely your sensor is going bad and requires replacement. They're cheap and easy to find, especially if they're an Bosch unit like ours. Alternately, GM's version this part would be a good option.
5. Tachometer
A failing engine speed sensor could be the reason behind many issues in your car. It's a crucial component of the transmission in your Audi, as it transmits information to the ECU regarding how fast or slow the engine of the car is spinning. This sensor can cause the transmission to malfunction and other car components to be affected.
The G5 engine speed sensor is located at the outside 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 is then able to process this signal to control fuel, timig and boost as well as sends it on to the G5 tachometer in the instrument cluster. You can test the sensor for any failure by checking the continuity between it and the tachometer. You can also check continuity 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 the resistance to be around 1000 ohms in these areas. This is the same across the Audi 80-100-200-RS2 series, starting from the 1985 MC all the way up to the 1997 UrS AN and the 1995 RS2 DU So, you may find them in wrecking yards.