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New setup - should I see +5v at SYNC sensor?

PostPosted: Mon Oct 15, 2012 10:10 pm
by Forg
I've got a newly set-up M84, and was given advice on how to setup the CRIP by a guy who seems to generally know what he's doing; he's done quite a few Mx00-series, possible not an M84 though.

Anyhoo, I have a 12-tooth wheel for CAS, and a single tooth for SYNC in the dizzy. It was suggested I set the engine up at TDC, manually wind the crank back about 90 degrees or so (between two teeth), fit the dizzy so that turning the engine forward would trigger a SYNC, turn the engine again until the first REF signal fired; and the CRIP is the number of degrees left until the crank gets to TDC.

Now I was told I should see the CAS and REF signals trigger; the falling edge or leading edge, as I manually turn the engine. I had the ECU connected to the PC, but saw nothing; I'm seeing 40kPa from the MAP (which probably means wrong sensor config), temps for air & engine look OK, TPS is working; but I'm seeing nothing triggered as I turn the engine so those REF & SYNC teeth go past their various sensors. Both REF and SYNC are showing a fairly steady 3.71V to 3.73V, barely wavering at any time.

The REF plug is a bit painful to get to; but I've put a multimeter on the SYNC plug and it's recording no voltage at all. Is this my problem; should I be seeing voltage at the SYNC (and REF) plug if the ECU's "on" but there's been no attempt at cranking & no RPM etc?

Re: New setup - should I see +5v at SYNC sensor?

PostPosted: Tue Oct 16, 2012 5:42 am
by stevieturbo
If you mean manually as in turning the engine over by hand, I'd say you'd be very lucky to see any signals.

What sort of sensors are you using ? Mag or hall ?

Magnetic sensors will need rotational speed before any voltage is created to generate a signal.

Re: New setup - should I see +5v at SYNC sensor?

PostPosted: Tue Oct 16, 2012 8:55 am
by Forg
Sorry, should have been more precise; just aware of over-explaining being a problem.
tl;dr :)

Both are hall-effect, SYNC is whatever Bosch sensor is fitted to non-vacuum-advance Volvo 240 dizzies (except chopper removed & replaced with one with a single tooth), REF is a GT101 (have forgotten the brand - it looks like a black cylinder of maybe 2.5cm diameter & 8cm long). Wiring's all single-piece back to the ECU plug, both are shielded up to the dizzy, and there's a plug for the CAS wire near-ish the dizzy & a ~20cm unshielded section down to the CAS.

Maybe I should stop "worrying about it", disconnect the injector plugs and crank the engine, and see if I get RPM's? I guess RPM's indicate I'm getting REF sugnals, will the ECU through a fault of some sort if it doesn't get the expected SYNC signals while cranking?

Re: New setup - should I see +5v at SYNC sensor?

PostPosted: Wed Oct 17, 2012 7:06 pm
by PQatPIT
Forg wrote:Maybe I should stop "worrying about it", disconnect the injector plugs and crank the engine, and see if I get RPM's? I guess RPM's indicate I'm getting REF sugnals, will the ECU through a fault of some sort if it doesn't get the expected SYNC signals while cranking?

Ref and sync sensors should be set as hall sensors. Btw, Ref/Sync Capture function in Utilities menu is very handy tool. With that you can really see what kind of crank and cam signals ecu sees.

Also there is quite a big list of position sensor errors ecu can diagnose. Fiddle with software, it's all there including explanations in popup help files.

Also I suggest that you check out all those Motec Webinar videos now on YouTube. There is lots of great info on how to setup ecu properly. :)