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MikeDanger · Joined: 21 Nov 2002 Posts: 774 Location: Denver

where does the 931 s2 get its tach signal from?
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It was either this or a giant box of legos

GeorgeV · Posted: Wed Dec 18, 2013 10:41 pm Post subject:

the distributor?
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1981 932 with mods:
http://www.924board.org/viewtopic.php?t=37921

924RACR · Posted: Wed Dec 18, 2013 11:46 pm Post subject:

Actually, no, from the coil... of course the coil's activated by the electronic ignition, which uses the crank sensor (at the flywheel) to detect rotation and timing.

If it's all working properly, you should see the tach flutter when cranking. If no operation at the tach, verify conductivity to the green wire (IIRC) at the coil.

HTH...

PS - the dizzy on the S2 only serves to distribute the spark, no other function; if you look inside, you'll see it's an empty shell...

ptheskil · Joined: 03 Aug 2004 Posts: 128 Location: Essex, UK

I beg to differ but note that my experience is with ROW vehicles. The S2 has a dedicated output from the DITC unit which drives the tacho directly. The s2 tacho is unique but can be replaced with an "ordinary" one and the wiring changed to drive it off the coil as the other models. In my experience the s2 tacho needle responds quicker to engine rpm changes than the standard ones. I am pretty sure that the DITC wiring is detailed on this forum (search) or you could try searching in an illegal online manual

If you hear a knock on the door don't answer.
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1981 931 series2 Euro spec

MikeDanger · Joined: 21 Nov 2002 Posts: 774 Location: Denver

hmmm ok, well, since I intend to use a Cam angle sensor inplace of the distributor, im trying to figure out where Id pull the signal from.

but if what you guy are saying, that the signal is NOT comming from the distributor?
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It was either this or a giant box of legos

ptheskil · Joined: 03 Aug 2004 Posts: 128 Location: Essex, UK

Correct. It does not come from the distributor. You should be able to pick up a s1 or n/a tacho for peanuts and wire it direct to the coilwhich will work with whatever ignition system you choose to users long as it is single coil single spark. I have not tried running an s2 tacho from the coil but it might work. On th otherhand it might not.
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1981 931 series2 Euro spec

924RACR · Posted: Sun Dec 22, 2013 12:05 am Post subject:

Better answer is a new crank sensor angle pickup like the ones Dan sells, since the original ones are NLA.
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