Bad replacement G28 sensor probable.

[Jim Hollander at Hot Grips Mfg., Inc.]

Yes, the meter was set on 2k ohms scale, zero'd out before the test.  I see 
now what happened.  I started with a good G4 and a bad G28 originally, 
sitting side by side in that bracket.  I received a bad NEW G28 from the 
parts counter, and in my struggle to remove the original bad G28, I must 
have damaged the wires where they come out of the G4.  Removing that first 
G28 was ridiculous.  It wouldn't push out, couldn't heat up the aluminum 
bracket without damaging the G4 next to it, took a Dremel tool to cutting 
off the original stuck bad G28, then pushed out the guts of it with an air 
hammer.  No easy way to hold the aluminum bracket while using LP torch to 
heat it, it just got crude and maddening.  So I end up with 3 bad sensors. 
Just one of those situations where a lack of patience and circumstances 
conspire to make the whole situation take much more time than it should. 
Frustration and a painful lower back working on it for hours took its toll.

> Message: 4
> Date: Mon, 22 Nov 2010 14:35:24 -0700
> From: "Mike Sylvester" <mike at urq20v.com>
> Subject: RE: Frequency of faulty NEW engine rpm speed sensor G28 ?
> To: "Jim Hollander at Hot Grips Mfg.,Inc." <Jim at hotgrips.com>
> Cc: 200q20v at audifans.com
> Message-ID:
> <20101122143524.195365548da1c44eaf4974b0054c21d8.23c604be73.wbe at email00.secureserver.net>
>
> Content-Type: text/plain; charset="utf-8"
>
> Are you sure your ohm meter is working and that you have it on the
> correct setting?
> That seems more likely than 2 bad G28s and a bad G4.
>
> Mike
>
> www.urq20v.com
>
>> -------- Original Message --------
>> Subject: Frequency of faulty NEW engine rpm speed sensor G28 ?
>> From: "Jim Hollander at Hot Grips Mfg., Inc." <Jim at hotgrips.com>
>> Date: Mon, November 22, 2010 4:29 pm
>> To: <200q20v at audifans.com>
>>
>>
>> My Vag-Com identified a faulty engine rpm sensor G28 on my '91 200 TQ 20v 
>> so
>> I ordered a new one.  Bentley Manual advised to check that ohms between
>> terminal 1 and 2 be approximately 1000 ohms, with terminals 1-3 at open
>> circuit, and 2-3 open circuit as well.  When I got the G28 sensor I was
>> curious and checked the new one with my ohm-meter and the reading on all
>> combinations between the 3 terminals was an open circuit.  I wondered if 
>> the
>> reason there was no ohms reading between terminals 1 and 2  might be 
>> because
>> the sensor needed to be positioned over the flywheel teeth to get a 
>> correct
>> reading.  But if there is a coil inside the sensor shouldn't there be
>> approx. 25 ohms at all times regardless of proximity to flywheel teeth?
>>
>> I installed the sensor, and the reading did not change once it was in 
>> proper
>> position.  I plugged in the Vag-Com and still the code showed a engine 
>> rpm
>> sensor with no signal (bad sensor).
>>
>> What is the frequency of a new G28 sensor being bad, any feel for this...
>> anyone?
>>
>> My other question is:  There are two sensors (G28 and G4) on that 
>> aluminum
>> cast bracket that sits above the flywheel teeth.  Is the only difference
>> between them the color of the connector being tan or black, with their 
>> size
>> and ohms, functionality being identical otherwise?  In other words, if I
>> kept track of the connectors, can they be interchangeable?
>>
>> Removing the old engine rpm speed sensor G28 was no picnic, and a bit of
>> abuse befell the other sensor  G4 (black wire end connector at the 
>> bracket
>> behind the engine on the firewall) next to it, because after installing 
>> the
>> new (bad) engine rpm speed sensor G28 my Vag-Com now showed both a bad
>> engine rpm sensor G28 and a bad ignition timing sensor G4 too.
>>
>> It was very discouraging going from one a bad G28 to a bad G28 AND a bad 
>> G4
>> sensor.  But if these G28 NEW sensors often come in bad, then it all 
>> makes
>> sense.  Should I just order another G28 and insist on checking the ohms
>> between terminals 1 and 2 at the parts counter before accepting it? Of
>> course I will bring a copy of Bentley page 28.41 where the 1000 ohm test 
>> is
>> described.
>>
>> Jim
>