[Ecotec] Cam Crank Voltage

[07GTS]

I don't think it's 5v disconnected. I believe the sensors has a resistor that pulls the 12 volt down to 5....

I'm going to run with Haltech's advice that it takes 12 volt in. It's going to be a massive job if it's wrong, because my 12 volt is in the engine bay and my 5 volt supply is from the ECU and they need to be shielded wires.

they should pull down to zero, could be 5v to 0 or even 12v to 0, they are looking for a pulse so it needs to be at zero or extremely close, they work two ways the sensor is zero then pulses out 5 or 12v, or there is already on the signal wire 5 or 12v and the sensor pulls it down to zero,

easy way to test is plug sensor in or just wire it up off the vehicle and then put metal to the front of it with multimeter on the signal wire (dc volts) and earth and it should pull to zero with the metal in front and then remove metal and it will go back to the reference voltage 5 or 12v

 

[Draimond]

Just to throw a spanner in the works I did some testing.
You know, I'm only just realising now that I didn't directly ground the DFI modual... so these readings probably don't mean anything... hahaha

 

[07GTS]

what earth were u using for those tests for multimeter ? should be using the sensor earth middle pin then check the power and output pins to see what they read, cos it an above earth type sensor other earths may not read right

 

[Draimond]

I was using the main chassis / engine ground... aka the batteries negative terminal.
See the other two photos, the multimeters negative probe is under the alligator clamp on the negative terminal.

 

[Draimond]

I'd still like to get this all worked out and documented. But plan B... which is looking like plan A at the moment, will be to crank the engine with injectors disabled once the Haltech install is finished and just data log the cam and crank input. Making sure to set those AVI's to 12V first. Once I know what my high and low voltage levels are coming out of the two trigger sensors, I can then make a config to suit.

Side note, I'm slightly surprised I've never heard anything about the trigger system on these cars being problematic. Not only are the signal wires for the trigger system unshielded but they're right next to what I'm told are supposed to be some pretty noisy wires.
Obviously the L27, L36, L67 never got the breadth of r&d that RB's for an example have had. But still.
It's just weird being told something is absolutely critical in theory yet mostly absent in practise.

 

[07GTS]

try that same test using the sensor earth middle pin, being it was showing a voltage with another earth could be an issue ? it should have been showing zero or small millivolts from noise, if the other two pins voltage changes using that middle as earth then its not earthing properly check between chassis/battery earth and that middle earth pin see if its dead short or has resistance

 

[Immortality]

Are both pins M and L from the DFI module grounded to the battery?

 

[Immortality]

Note, I'm slightly surprised I've never heard anything about the trigger system on these cars being problematic. Not only are the signal wires for the trigger system unshielded but they're right next to what I'm told are supposed to be some pretty noisy wires.
Obviously the L27, L36, L67 never got the breadth of r&d that RB's for an example have had. But still.
It's just weird being told something is absolutely critical in theory yet mostly absent in practise.

The DFI is a complete self contained ignition control unit so I'd image there is some good filtering going on inside the unit and the coil control circuits are isolated from the sensor circuits.

As long as the power supply to the sensors is clean it shouldn't be a major issue. I had the unfortunate experience of having a very reputable dyno shop fit and wire a electric dizzy to a old car of mine. Instead of using the clean power feed from the ECU they used 12volts directly from the coil positive post. At idle my timing was varying 6° or more with the timing light on the balancer. I chased that fault for ages and only discovered the wiring **** up when I cut the wiring loom up to get it out of the car! To say I wasn't pleased with outfit would be an understatement but it sent me down the rabbit hole of learning to it myself.

 

[Draimond]

Are both pins M and L from the DFI module grounded to the battery?

No that's what I was saying before...
Because I did this test on a work bench and not in the car, the DFI modual isn't bolted to the engine so it wouldn't be grounded.
(Assuming the DFI modual grounds to the engine through it's metal base)

I'll do it all again with the DFI modual grounded.

 

[Draimond]

That's making more sense.

Still weird that the signal input wire would have voltage. I would have thought the voltage input would be altered by the hall effect sensor and the resulting voltage would be sent up the signal wire.