[urq] reference sensor bench testing

Sat Aug 29 16:55:38 PDT 2009

Peter,

not sure on the 20V if there is an insitu test for the sensor but there is for the UrQ and it failed that. I Ohmed it and it is about 110 Ohms off a similar MC sensor, 850 vs the MC 970.  I'd consider both pretty close to the 1,000 Ingo referred to. (the MC unit is physically much shorter and has a slightly bigger in diameter, I'd guess you could shim an UrQ unit to work in later cars, but not vice versa)    I'll go back to the car when I can and ohm the "good" speed sensor.  Your 20V experience seems like it may be the first fire up after a transplant?  My car was running one minute and wouldn't start literally a minute later.  As many tbelts go/skip on start that is entirely plausible as I have not yet physically checked TDC marks but will when I can have someone with experience help.  Alterantively I tried to swap the speed sensor over (as they are the same) but didn't have the necessary tool to get a got grip on it to pull out.  (the car broke down at an intown parking garage)  At least it is free moving and won't present the issues Louis Alain had!

Mike

Date: Sat, 29 Aug 2009 17:26:16 -0600
Subject: Re: [urq] reference sensor bench testing
From: audionly at gmail.com
To: mdeltergo at hotmail.com
CC: ingo.rautenberg at gmail.com; urq at audifans.com

The pin moves a magnet in the sensor. An ohm meter won't pick up the signal of the pin. You need a scope to see the differential. Make sure you get one to do the testing before you go any further. I/we have been down this road before with Dennis Graber's 20V. After everything was said and done we found that somewhere between the flywheel mark (through the crank, through the crank timing gear, through the timing belt, through the cam ) to the timing mark on the distributor had lost 3 or 4 degrees even though the marks said both were on top dead center.  We kept thinking it was the reference sensor because of the readings. We eventually advanced the distributor a couple of degrees and the car fired right up. As we speak; Dennis is trying to find out where the slip happened.

Regards,

Peter

On Sat, Aug 29, 2009 at 5:08 PM, Mike Del Tergo <mdeltergo at hotmail.com> wrote:

Ingo,

I had thought that the reference pin swinging by generated and electrical field of some measurable output and thought there might be another way to generate a field and measure.  I will Ohm the unit for starters.

Thx

Mike

> To: mdeltergo at hotmail.com; urq-bounces at audifans.com; urq at audifans.com
> Subject: Re: [urq] reference sensor bench testing
> From: ingo.rautenberg at gmail.com
> Date: Sat, 29 Aug 2009 22:02:19 +0000

>
> It's basically the same for as for the V8, 5ktq, etc.
>
> I forget the order, but there are 3 pins in the connector and the center pin -- when connected to one of the side pins with a multimeter should ohm out to 1k ohm. If it doesn't, it's bad. Sometimes the sensor can be flaky at only higher temps, so this method really only works to tell you if you have an absolutely dead sensor.
>
> HTH
>
>
> Ingo Rautenberg
>
> -----Original Message-----
> From: Mike Del Tergo <mdeltergo at hotmail.com>
>
> Date: Sat, 29 Aug 2009 21:49:22
> To: <urq at audifans.com>
> Subject: [urq] reference sensor bench testing
>
>
>
> Has anyone run across a way to bench test the flywheel reference sensors Audi uses? One in my UrQ tests bad through the harness but of course it is not unheard of to lose the reference pin so I wanted to bench test before ponying up for OEM.
> Mike
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