Gimme a shout if you need the scope to bottom out the timing issues.
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Paul Nugent
Webmaster http://S2central.net
Administrator http://S2forum.com
1994 S2 Coupe ABY - aka Project Lazarus
2001 A6 allroad 2.5TDi - family tank
2003 S4 Avant 4.2 V8 - daily burble
Purveyor of HomeFries and Exclusive agent for Samco hose kits (S2/RS2)
There are only 10 kinds of people that understand binary - those that do, and those that don't
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Hi Paul,
Originally posted by S2central.net View PostAnd they say Motronic is complicated - LOL... Seriously though - good luck Des... trying to work out if the reference pin needs to be magnetic or not.
On motronic the crank reference signal has to arrive within the 'hall window' -
looks like VEMs is same in this regard when I skim this thread. Don't forget I still have your sillyscope here - that would be useful here to 'see' what signals you get on a cold crank. I was using it today helping a friend condemn an O2 probe on a 996.
Incidentally its probably easiest to do that with engine running on motronic. just "back probe" the pins at the connector with the rubber boot pulled back a bit. works good, BTDT.
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@marc - I had never tried to see how much motronic would accept there for misalignment - but the reference mark is supposed to arrive within the window. Clearly Mr Bosch designed some room for movement there.Paul Nugent
Webmaster http://S2central.net
Administrator http://S2forum.com
1994 S2 Coupe ABY - aka Project Lazarus
2001 A6 allroad 2.5TDi - family tank
2003 S4 Avant 4.2 V8 - daily burble
Purveyor of HomeFries and Exclusive agent for Samco hose kits (S2/RS2)
There are only 10 kinds of people that understand binary - those that do, and those that don't
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Update then. So I checked the timing marks and sensors. Everything was where it was ment to be. I swapped the two crank sensors for another set. And now the problem is almost cured! I say almost as when cold there is still the odd trigger fault maybe 2 times a minute.
Any ideas? What should the clearence between sensor and pin be. Cheers.
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This will be useful for comparison - http://www.s2forum.com/forum/showthr...d=1#post498878
See you tomorrow AM DesPaul Nugent
Webmaster http://S2central.net
Administrator http://S2forum.com
1994 S2 Coupe ABY - aka Project Lazarus
2001 A6 allroad 2.5TDi - family tank
2003 S4 Avant 4.2 V8 - daily burble
Purveyor of HomeFries and Exclusive agent for Samco hose kits (S2/RS2)
There are only 10 kinds of people that understand binary - those that do, and those that don't
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Interesting... clearly you are getting some rogue pulses. Motronic must have superior filtering to avoid the rogues. It would seem that VEMS is purely triggering on the pulse edges, but if it also had a pulse threshold detection that would nicely filter out the rogues.
It should also be possible the create an external circuit that pre-processes the G4 pulse to clean it up before the VEMS ECU. Analog stuff isn't really my bag, but I would be drawn to some sort of comparator circuit with a threshold level that is used to gate the good pulse... Look at difference in voltage of the good and bad pulses. It might even be worth using a potential divider to reduce the amplitude on both pulse types - this might bring the rogue pulses inside a window where they are correctly ignored by VEMS... whilst keeping the good pulses large enough for healthy detection.
Aren't oscilloscopes brilliant though !!!!Paul Nugent
Webmaster http://S2central.net
Administrator http://S2forum.com
1994 S2 Coupe ABY - aka Project Lazarus
2001 A6 allroad 2.5TDi - family tank
2003 S4 Avant 4.2 V8 - daily burble
Purveyor of HomeFries and Exclusive agent for Samco hose kits (S2/RS2)
There are only 10 kinds of people that understand binary - those that do, and those that don't
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Des, if it makes a difference, that pin looks definitelly bigger than the piece we made on my flywheel. BUT i cannot be sure if that could cause the problem, as this is something completelly new here.
i aggree about the trigger setting. Mine is set to 58 as well, although on older version (1.1.27)
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Originally posted by diesel des View PostOk so now my car runs on VEMS but gets some trigger faults causing PING in engine. Look at the scope. Blue is crank pin, yellow the cam. The 7A flywheel gives 2 small extra pulses before and after the main crank pulse confusing vems.
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This is great feedback guys. Ok Marc, yea both the vems ecu's have the cam invert BUT on the wiki page the guys are now saying that it might cause a problem. What ya think??
http://www.vems.hu/wiki/index.php?ac...%2FDesmondAudi
Paul, yea im sure the input could be processed to help vems out, but thats yet another box of bits which i could do without. And vems is ment to be a simple plug in setup, even with the 7a flywheel, so i think the software can be sorted to deal with this.
Jamo, thats interesting about the teath setup. I will ask Peter my supplier to confirm. Also will check about the injectors.
Cheers guys.
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If vems is plug and play then why is hall cam signal inverted ?Paul Nugent
Webmaster http://S2central.net
Administrator http://S2forum.com
1994 S2 Coupe ABY - aka Project Lazarus
2001 A6 allroad 2.5TDi - family tank
2003 S4 Avant 4.2 V8 - daily burble
Purveyor of HomeFries and Exclusive agent for Samco hose kits (S2/RS2)
There are only 10 kinds of people that understand binary - those that do, and those that don't
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