Rev counter / Tacho operation from aftermarket ECU

[Turn & Burn]

I’m aware that this subject had been posted before but thought it warranted a 2nd thread.
I’ve been looking at operation of the tacho from an ECU, the standard 240/260 current sensing tacho will not function from an ECU, so I’d got in touch with Chris @Spiyda Ltd as they crop up when you research this.
He said the Z tachometer is a copy of the Smith’s RVI unit (manufactured under licence) as fitted to many British cars and recommended one of their internal boards (£42) as a direct replacement for the existing board inside the tacho.
Fitting involved disassembly of the existing tacho unit, removal of the existing board and making off 5 soldered wires, the board mounts pick up the existing internals.
Testing was a bit tricky and required purchase of a Signal Generator (only £5 off eBay) but after a bit of a learning curve everything was sorted and the tacho is spot on although my needle is a touchy sticky prob due to age. In a car that vibrates and constantly moving rpm I don’t think this will be an issue.
Not fitted in the car yet, but so far I’m pleased with the result.

 

[jonbills]

Did you get the discount Andrew?
https://zclub.net/community/index.php?threads/spiyda-discount-code.26963/#post-307821

https://zclub.net/community/index.p...hometers-based-on-the-smiths-rvi-tacho.26962/

 

[Turn & Burn]

I wasn’t aware it was available, missed that.
Tbh my post looks a bit like advertising, it’s not, but I was genuinely pleased to get it working!

 

[jonbills]

I wasn’t aware it was available, missed that.
Tbh my post looks a bit like advertising, it’s not, but I was genuinely pleased to get it working!

Absolutely, by all accounts it's a great product/service.

 

[peter_s]

Fantastic! I'm just in the process of needing this myself.

Yours looks like an 77 or 78? I thought you could just disconnect the resistor feeding into the tacho and it should work?

 

[Russell]

I still have a load of boards left from the batch I ordered - https://zclub.net/community/index.p...r-tach-to-work-with-modern-ecu-signals.23237/

 

[Turn & Burn]

Fantastic! I'm just in the process of needing this myself.

Yours looks like an 77 or 78? I thought you could just disconnect the resistor feeding into the tacho and it should work?

There’s no resistor in the tacho feed, I think that’s possibly 280z? mines a late 260z and had a single line through from the coil, this goes onto an inductive loop on the tachometer rear.

 

[peter_s]

Ok, sounds reasonable. Mine has the resistor and is a 280z. What year is your car?

 

[Turn & Burn]

Ok, sounds reasonable. Mine has the resistor and is a 280z. What year is your car?

It’s a uk spec 1977, possibly US cars were different.

 

[peter_s]

Maybe, but they should be the same if you have the fuel injection. My resistor sits where the external voltage regulator is located in the engine bay. All these inconsistencies doesn't make it easier sometimes

I probably need this kit to make it work with my aftermarket ECU. But I'll try first without.

 

[Turn & Burn]

Maybe, but they should be the same if you have the fuel injection. My resistor sits where the external voltage regulator is located in the engine bay. All these inconsistencies doesn't make it easier sometimes

I probably need this kit to make it work with my aftermarket ECU. But I'll try first without.

It’s a 260z it was on carbs

 

[peter_s]

It’s a 260z it was on carbs

That explains it. I thought the later 260Z shared the injection with the 280Z

Interestingly there is a guy here locally that has a 75 280Z, that was imported by an official Datsun dealer and sold....

 

[Fairlineguy]

When I fitted a Rb25 I wanted to retain all the original gauges.
The original 240z rev counter is an inductive loop this company make
An adaptor
https://www.technoversions.com/TachMatch.html

 

[Fairlineguy]

Worth mentioning if you using a aftermarket ecu with wasted spark cop coils . Forget the ecu tach output
If you power your coils through the original inductive loop tach wiring (same way the original coil was feed)
you tach will work

 

[RBC210]

Hi all, I’ve got a 1978 C210 skyline with an RB transplant.
Running a PLMS equipped R32 GTR ECU.
I’m keen to get the factory Tacho working with this setup and wanted to ask if your still offering this service?
I’ve got a spare Tacho I can send.

 

[AliK]

I tried the Spiyda board but didn’t have much luck with it - having a degree in it and spent a life time playing with them, I like to pretend I know my stuff with electronics. So I definitely didn’t make incorrect connections etc. but eventually gave up with it - would have been easier to have replaced a couple of caps and transistors on the original board

However, you can send your tach to Spiyda and they will for around £70 take the hassle out of it and convert it for you. Really nice chap and very helpful / good support!

I’m very tempted to try Russell’s solution next.