[urq] Starting issues... Hall Sender?

[Ado Sigal]

You are indeed right Claus, thanks for clarifying it, the difference is 
one uses electromagnet and the other  permanent magnet, my mistake, I 
call them both Hall. The rest of advice is OK.
BTW, had to drop in the VR for 0.4mm after changing the flywheel on my 
present Urq, in order to get reliable signal from the pin sensor, of 
course three empty batteries after.

Cheers,

Ado
.

Claus Vegener wrote:

> Hall senders is not the same as VR (variable reluctans).
> The standard senders for the pins at the back of our 5I engines are VR 
> senders which as described
> are magnetic pickups with no external power and giving a fallen slope 
> curve with a height depending
> of the speed of the wheel. (only the impulse is used).
> A Hall is another type of sender. Used in the distributor and requires 
> at least 5 Volt as supply to work.
> Also used at an AAN engine as camsensor inside the upper camgear wheel.
> A Hall sender gives a more constant signal as it is not that much 
> depending of the speed of the moving metal theeths
> in front of it or through the air-gap in Audi applications.
>
> How I know this --- battling months with VR sender at my 034EFI system.
> Would not count 60-2 wheel at al speeds and vibrations
> Problems solved with the use of a universal Hall.
>
> Claus
> Urq 1983 20V 034EFI stage II
> Audi 200 20V Avant 1990
>
> ----- Original Message ----- From: "Ado Sigal" <a.sigal at bluewin.ch>
> Cc: <urq at audifans.com>
> Sent: Thursday, June 07, 2007 5:40 AM
> Subject: Re: [urq] Starting issues... Hall Sender?
>
>
>> Hall sensors are simple coil on magnet design and you can check any of
>> them simply for continuity, and no contact with the body. Weak signal is
>> usually ferrous debris on the magnets, or distance between the pin and
>> the sensor. If the sensor is stuck, its not the oxide fusion problem,
>> because the sensor body is SS and top is plastic, so gentle shock and
>> some lube will do, but you shouldn't twist it, but pry it out
>> vertically, starting with a thin knife and more lube and it will come
>> out. Naturally, check if is OK first and check the plug contacts for
>> corrosion. Symptom of working before but not after stationary period
>> suggest the corrosion, so check all three sensor plugs first.
>> SS and RMS sensor you can energize by flicking screwdriver over its
>> magnets, which should give you a measurable signal, although the
>> continuity test tells the story first. Distributor same, position it
>> when the window is just to enter the hall coil, mark the position,
>> loosen the clamp and flick it around. That should give you measurable
>> signal. Of course, return to mark and tighten.
>>
>> HTH, Ado
>>
>>
>>> The starting problem returns!
>>>
>>> I was just starting to work on some extra goodies on Gobi this
>>> weekend (early morning) when I was getting ready to run her up some
>>> ramps... she wouldn't start. Okay, been through this process before,
>>> right! Did all the usual "car does not start" diagnostics and the
>>> only thing I came up with when I was using my homemade LED test light
>>> at the ECU, was when I cranked the engine while testing the Hall
>>> Sender, the light stayed on constant, not flickering like the manual
>>> stated. Then I checked the Reference Mark Sensor (with LED) and
>>> thought the pulsing signal was a very weak. I have since replaced the
>>> Speed Sensor with the same symptom (weak signal) and she fired right up.
>>>
>>> Okay, now that you know the background. Here's what I must ask. If
>>> the test light for the Hall Sender doesn't flicker, does that mean
>>> it's faulty and needs to be replace (not sure how to do this yet) or,
>>> is it a faulty Reference Mark Sensor? If it's the RMS, I can't budge
>>> the damn thing! I think the aluminum sleeve has fused with the tranny.
>>>
>>> Any advice on this? I need to get her back on the road for the next
>>> event in two weeks.
>>>
>>>
>>>
>>>
>>
>>
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>
>