Problems starting when warm
#12
Re: Good question. i don't know the answer.
There are three sensor which must be working in order for the engine to start.
1. Hall Sensor (Located in the right side distributor) Engine will run, but there is a loss in power.
2. Crank position sensor (Tell the ECU when number one piston is approaching TDC. The sensor is timed for 62 degree before TDC). Unlike the 5 cylinder engine the V8 doesn't have a cold start valve. Instead the ECU start the sequence of firing the injectors base on the signal from the crank position sensor.
3. Speed sensor tells the ECU the engine speed.
1. Hall Sensor (Located in the right side distributor) Engine will run, but there is a loss in power.
2. Crank position sensor (Tell the ECU when number one piston is approaching TDC. The sensor is timed for 62 degree before TDC). Unlike the 5 cylinder engine the V8 doesn't have a cold start valve. Instead the ECU start the sequence of firing the injectors base on the signal from the crank position sensor.
3. Speed sensor tells the ECU the engine speed.
#13
Re: Is'nt the crank sensor used when the engine is running to tell the ecu the timing is right?
Don't forget to check the hall effect sensor on the distributor (at least on 5cyl cars). It too can cause a no-start or intermittant start problem. BTDT.
#14
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Audi V8 reference sensors
The crank position sensor is used by the engine when it is running, but will default to a value when the engine was started if it should fail while the engine is running. The engine will remain running. Once the engine is turned off the engine will not start until the sensor has cooled down.
How do you tell which sensor is which when you get in there?
How do you tell which sensor is which when you get in there?
#15
Crank sensor
The crank position sensor is used by the engine when it is running, but will default to a value when the engine was started if it should fail while the engine is running. The engine will remain running. Once the engine is turned off the engine will not start until the sensor has cooled down.
How do you tell which sensor is which when you get in there?
How do you tell which sensor is which when you get in there?
The crank sensor reads a "pin" on the flywheel as it passes over the crank sensor. The speed sensor is located above the the flywheel and reads the teeth on the flywheel to determine engine speed. Remove the sensor and look into the hole, if you can see the flywheel teeth then it is the speed sensor. I agree that it is most likely the crank sensor causing your problem. You can also raise the hood to allow for the hot air to escape, this will help to get the car started in an emergency. Both sensors speed and crank are magnetic sensors and as we remember from High School physics, a magnet loses it magnetic property when heated.
HTH
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