Increase VN V6 S1 DFI Tacho Signal output ??

Holden/Delco Tuning. ALDL, OBD 1.5. Circa 1989 to 2004.
S1VNV6Hilux
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Increase VN V6 S1 DFI Tacho Signal output ??

Post by S1VNV6Hilux »

Does anyone no of a way to increase the signal output on the vn v6 series 1 dfi? I need more than 5v output to get my Marks 4wd tacho interface to work. I know i can fix this by installing a series 2 dfi module. But i am just wondering if there is a simple inexpensive way of doing it?
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VL400
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Re: Increase VN V6 S1 DFI Tacho Signal output ??

Post by VL400 »

I have used relay coils to provide a higher voltage spike for some conversions. You need to use a non-resistor type relay and rip out the switch mechanism inside it - otherwise it buzzes :P

Make up this little circuit, it can all fit inside the relay housing too..
https://pcmhacking.net/forums/viewtopi ... lay#p21551
S1VNV6Hilux
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Re: Increase VN V6 S1 DFI Tacho Signal output ??

Post by S1VNV6Hilux »

Cheers VL400 - i was looking and looking through posts but couldn't find anything. your a bloody legend!! :punk:
S1VNV6Hilux
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Re: Increase VN V6 S1 DFI Tacho Signal output ??

Post by S1VNV6Hilux »

Does anyone else out there have a different way of doing this? or have maybe used this method on a VN S1 V6 and knows it works without causing any issues ?
VK_3800
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Re: Increase VN V6 S1 DFI Tacho Signal output ??

Post by VK_3800 »

So installing a series 2 module isn't the simplest and most inexpensive option...? They seem to be plentiful around here and its only one plug.

Or are you saying that it might be a long shot?
S1VNV6Hilux
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Re: Increase VN V6 S1 DFI Tacho Signal output ??

Post by S1VNV6Hilux »

VK_3800 wrote:So installing a series 2 module isn't the simplest and most inexpensive option...? They seem to be plentiful around here and its only one plug.

Or are you saying that it might be a long shot?

Series 2 DFI solves the problem - cost medium
VL400's solution will definitely increase the signal - cost ultra low - but i was looking for people who have used this to boost the signal and their opinions on it and weather or not it interferes with the sine wave
OR if anyone else had come up with a similar circuit design to VL400 because there is always more than one way to skin a cat as the saying goes. Thanx for you input :thumbup:
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charlay86
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Re: Increase VN V6 S1 DFI Tacho Signal output ??

Post by charlay86 »

I can't think of anything simpler that uses fewer components than this basic design.
There is no sine wave here to interfere with; the circuit works because it is using a square wave to switch the transistor.
when the transistor conducts, a magnetic field is generated in the coil.
when the transistor switches off, the magnetic field in the coil collapses and produces a negative high voltage signal that is fed into the tacho input.
S1VNV6Hilux
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Re: Increase VN V6 S1 DFI Tacho Signal output ??

Post by S1VNV6Hilux »

charlay86 wrote:I can't think of anything simpler that uses fewer components than this basic design.
There is no sine wave here to interfere with; the circuit works because it is using a square wave to switch the transistor.
when the transistor conducts, a magnetic field is generated in the coil.
when the transistor switches off, the magnetic field in the coil collapses and produces a negative high voltage signal that is fed into the tacho input.
thanx for the input :thumbup: i was concerned about the sine wave from the sensor but from what i can gather the dfi module converts it to a square wave?? i could be wrong again ? the connection i need to boost is pin G on the the dfi from the CAS sensor and then it goes into the Marks 4wd tacho interface then to my tacho - the purpose is to convert my 4cly hilux tacho to work with the vn v6. i always willing to learn :?
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DieselBob
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Re: Increase VN V6 S1 DFI Tacho Signal output ??

Post by DieselBob »

Have a look here
https://pcmhacking.net/forums/view ... =31&t=1015
The G input is from the hall effect sensor, this is not a definite switched voltage but more of a ramped signal.
There a circuits in the DFI to clean this and make it more digitally friendly.
The G input shows 18 pulses per rev. not really usable as an input for a aftermarket tacho.
The H Input shows 3 pulses per rev. might be a better option..
The E output is a dash feed and a diagnostic connection for a handheld workshop tacho....
Hope this helps....
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VL400
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Re: Increase VN V6 S1 DFI Tacho Signal output ??

Post by VL400 »

Ahh so your not using the tacho out on pin E....

Unless its different on S1, from my testing the 18x signal is a pretty well defined square wave - but you do prob miss out on some filtering inside the DFI module. You could use it as a tacho signal with a divide by N box - which is what the marks 4wd box is doing, divide by 9 for 4 cyl tacho. Anyone know the electrical difference on S1 vs the later style?