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Trigger issues


Usav8or

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Trying to help out a friend this time and were having some issues with getting the crank and cam sensors setup on a BMW S14. Attached is a trigger scope that looks to me like neither sensor is getting much of a signal. Both the Crank and cam triggers are VAC Motorsport products, though the crank trigger wheel was special made elsewhere for some sort of clearance issue with a cover. It is still 36 minus 2, just a slightly smaller diameter. I've had to lower the arming thresholds down to .2 in order for the ECU to pickup a signal. The current setup is a BMW S14 with direct spark ignition (LS4 coils I believe) and OEM injectors. The alternator belt isn't on yet, so its powered externally at this point. I'm not a tuner by trade, but I did successfully get my E30 with an M20 going a few years ago using a G4+ Thunder. Were still in the early stages of configuring the details, but any assistance would be appreciated. Thanks

999.llgx BMW 2002 M2 Configuration.pclx

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That scope shows no signal at all.  Are you sure the capture button was only clicked when the engine was cranking - and not before?

Also, looking at a pic of the VAC cam trigger kit, it looks like an aluminimum disc with a magnet in it, so most likely the sensor is a hall effect rather than reluctor.  

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3 hours ago, Adamw said:

That scope shows no signal at all.  Are you sure the capture button was only clicked when the engine was cranking - and not before?

Also, looking at a pic of the VAC cam trigger kit, it looks like an aluminimum disc with a magnet in it, so most likely the sensor is a hall effect rather than reluctor.  

I'll try this again, and I'll ask about the trigger wheel.  Thanks, Jeff

TriggerScopeLog888.llgx

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Still nothing at all on either trig 1 or 2 in that scope.

So are you 100% sure this was captured when engine was cranking?  Because usually even if there were no trigger signals or the sensors were completely disconnected even, you would still usually see a bit of wave caused by the high starter motor current offsetting the ground, but this scope shows dead flat lines very much like it is a capture of a stationary engine.  

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Thanks, I’ll have to look at it again in a day or two. I’m not doing something right. Is there a way I can look at the capture after it’s been saved? I’ll also need to get a definitive answer on the construct on the trigger wheel they had made. I suspect it looks like the VAC wheel, but made out of steel and without a magnet, just the 2 missing teeth. Thanks again for your time and assistance. 

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7 hours ago, Usav8or said:

Is there a way I can look at the capture after it’s been saved?

It is saved as a .llgx file so just view it like any other log.  >logging>open log file.  Typically you would view it as a time plot - so create a new page, add a time plot, then add the trigger scope parameters to it.  

 

7 hours ago, Usav8or said:

I suspect it looks like the VAC wheel, but made out of steel and without a magnet, just the 2 missing teeth.

Its only the Vac cam trigger disc that has a magnet - that why I suspect the cam sensor is a hall (they should know as you would have to wire power to it if it is a hall).  The Vac crank disc is a fairly standard issue steel trigger disc, although I dont like their design much for a reluctor but it should work provided the sensor is somewhere close to the wheel and lined up.  

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The Cam sensor is a Hall sensor, and the crank is a reluctor. I've double checked the connections to both and everything checks out fine. However, it doesn't seem like either trigger is getting power during the crank. Is there a setting somewhere that will cut power to the sensors, or should there be a digital input (ignition switch) setup to tell the ecu when the ignition switch is in start or run? We're not using the ECU hold power feature on this build so the ignition switch in DI has been set to "Always on." Should it just be set to "OFF." Attached is the last trigger scope attempt of the day, hopefully I did it right this time. 

 

Thanks, Jeff

TriggerScopeLoglast2.llgx

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Trigger 1 is showing noting.  Trigger 2 is showing a constant 1.4V which suggests a wiring issue.  It should be either 0V or 4V, nothing in between.  

The ECU doesnt supply power to the sensors and there is nothing that would make the scope show no signal if there were a signal.  The Ign sw setting is fine as is.

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  • 2 weeks later...

Problem solved after some investigation. The BMW s50 cam sensor was changed from a reluctor to a 12v hall effect sensor following a TU. Now it starts and runs at idle. Next up is working out a fuel table. I don't suppose anyone has a fuel table or base map for a BMW s14 they'd like to share.

Thanks,

Jeff

runningTriggerScopeLog.llgx

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