Not sure what I missed - Engine Troubleshooting


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Not sure what I missed

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Trowa346
New User

Feb 1, 2012, 4:27 PM

Post #1 of 4 (1381 views)

Not sure what I missed	Sign In

2002
volkswagen
gulf
2.0
106k

before the car wouldn't start anymore it would randomly die. Now it won't stay running. will turn over like it wants to start. Error code I got was P0321

I've replaced my spark plugs, wires and coil pack. Car starts but runs real rough. Not like it was before when I had the problem. Black smokecomes the tail pipe. some white in the front. Not sure if there is something I'm or missed.

Discretesignals
Ultimate Carjunky / Moderator
Discretesignals profile image

Feb 1, 2012, 6:02 PM

Post #2 of 4 (1340 views)

Re: Not sure what I missed	Sign In

That code is for the engine rpm speed sensor (crankshaft position sensor). The sensor is a hall effect sensor which produces a digital square wave signal to be used by the ECU to determine the crankshaft's speed and position. Without the signal or proper signal from the sensor, the ECU will not be able to fire the ignition coils and injectors, therefore the engine won't start or stall if the engine is running.

The ideal way to check the sensor's output is by using an oscilloscope. If there is no signal or the signal is corrupted, you will be able to tell watching the waveform signal while cranking the engine.

You can also ohm the sensor out by disconnecting the sensor and checking resistance on pins 2 and 3 in the sensor's connector . The resistance should be around 730-1000 ohms. Also check for shorts between pins 1 and 2 and pins 1 and 3. If anything is out of spec, the sensor is faulty.

For more information on hall effect sensors watch this video:

http://www.youtube.com/watch?v=Exz4f4RfBFY

Since we volunteer our time and knowledge, we ask for you to please follow up when a problem is resolved.

(This post was edited by Discretesignals on Feb 1, 2012, 6:04 PM)

Trowa346
New User

Feb 3, 2012, 1:51 AM

Post #3 of 4 (1291 views)

Re: Not sure what I missed	Sign In

Found out what it was after fixing what I did and I was getting ready to what you said and noticed my fuel injector was loose. After I fixed that everything runs perfect. Thank you for your time.

Discretesignals
Ultimate Carjunky / Moderator
Discretesignals profile image

Feb 3, 2012, 6:01 AM

Post #4 of 4 (1284 views)

Re: Not sure what I missed	Sign In

That's interesting. If you have any problems, let us know.

Since we volunteer our time and knowledge, we ask for you to please follow up when a problem is resolved.

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