Classic Audi Technical Mech/Tech Engine » Ur quattro flywheel sensors

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Old 12-09-21, 02:45 PM   #1
lefthooker
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Default Ur quattro flywheel sensors

One plugs into the ECU loom, the other into the engine loom. Not sure which way around they should be as the connections appear to be identical, can anyone help?

Car is a 1981 WR.
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Old 12-09-21, 08:40 PM   #2
Colin Aitchison
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They both got back to the ECU, G4 - Ignition timing sensor, fits into the left rear of the engine block and looks for the timing pin on the rear of the flywheel , G28 - Engine speed sensor, fits into the top front edge of the gear box and counts the flywheel teeth, never fitted them round the wrong way, so can not confirm if that causes problems.
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Old 13-09-21, 04:06 PM   #3
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Quote:
Originally Posted by Colin Aitchison View Post
They both got back to the ECU, G4 - Ignition timing sensor, fits into the left rear of the engine block and looks for the timing pin on the rear of the flywheel , G28 - Engine speed sensor, fits into the top front edge of the gear box and counts the flywheel teeth, never fitted them round the wrong way, so can not confirm if that causes problems.
Thanks for that. Found that they do indeed both go back to the ECU

Still need to find out which is which, probably going to end up a case of trial and error.
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Old 13-09-21, 04:22 PM   #4
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Just had a look at the wiring diagram, G4 and G28 connect to the ECU pins as follows, G4 connects to pin 12, 13 and 25, 25 is the earth shield, 12 and 13 are the siginal wires, G28 connects to pin 11, 24 and 23, 23 is the earth shield, 11 and 24 are the siginal wires. There are two or three ways to test this with an AVO. but all involve removing the cable connector from the back of the ECU for testing.
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Old 13-09-21, 04:33 PM   #5
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Quote:
Originally Posted by Colin Aitchison View Post
Just had a look at the wiring diagram, G4 and G28 connect to the ECU pins as follows, G4 connects to pin 12, 13 and 25, 25 is the earth shield, 12 and 13 are the siginal wires, G28 connects to pin 11, 24 and 23, 23 is the earth shield, 11 and 24 are the siginal wires. There are two or three ways to test this with an AVO. but all involve removing the cable connector from the back of the ECU for testing.
That's excellent info. Thanks very much for your help.
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Old 13-09-21, 05:01 PM   #6
mikes2
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They're normally colour coded.

G4 is black

G28 will be grey
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Old 14-09-21, 12:31 PM   #7
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Quote:
Originally Posted by mikes2 View Post
They're normally colour coded.

G4 is black

G28 will be grey
Thanks for that
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