Tach Hookup - FJ60 12H-T install

[panoramic]

Creeker,
thanks for the kinbd kudos.

You are correct: We do NOT have a Fall Effect Sensor (FET).
Our OEM sensor is a simple 500 ohm pickup coil w/ magnet(s) on the flywheel.
It is NOT the var. ind. balanced bridge. as described by Honeywell. It *could* be, but I doubt it because there are definitely magnets producing the AC voltage.

On to discussing ISSPRO:

I called ISSPRO and talked with their engineering about the dial you mentioned: It will NOT work because they have a (undocumented) requirement for a *minimum* peak voltage that is too high.

ISSPRO could be made to work using:
A) A bunch of RS parts. This is not elegant or reliable and the whole solution is still on the pricey side for the gauge. I would probably also add a voltage regulator & support components. Now it is more complicated and too $$$ and I think I would rather just roll my own at this point!

...or..

B) ISSPRO said their waveform sensitivity could be adjusted, but you would have to remove the bezel to get at the circuit and you will destroy the case, void the warranty, make it look ugly... etc...Not worth it IMHO!


If you want to check with VDO and SW with the voltage & coil specs go ahead and let us know....

BTW: Pictured are my dial faces for 2H and 12HT and the ISSPRO unit - The RPM's are on target for what we need though.


Some other clarifications:
Hall Effect Sensors conduct in the presence of a magnet.
The coil produces current when the magnet MOVES past the coil.
The honeywell bridge coil changes inductance when a ferrous metal is in proximity.

I am also including the tach connections so that our Japanese brethren can help me decide what these tach wires are for!
I can guess red is 12V, but which is signal and which is ground?
Ie: "Hello, Mr. Mot-san!!! Please help decode this!
I am forwarding this thread to MOT. I hope he has a few seconds to help out.

- Eric

 

[panoramic]

Wow!, Mot is online so I got a response within 20 seconds. He is great.

The embossed Kanji symbols on the back of my tachs are silly.
They only say :from the left(red) wire, it reads "RED", "BLACK/YELLOW" and "BLACK".
That wasn't very helpful...

 

[panoramic]

Creeker,
I just wanted to be clear (since I babble) that engineering at ISSPRO (Bill Carson) indicated that their unit will not work as shipped. Also, the signal output from the Toyota Sensor is TWO wires from the coil, not one. If the sensor can be screwed in closer to the flywheel teeth, it may generate enough voltage to work. I have not removed my sensor to see this and I do not intend investigate the adjustment.

OK, telecon with ISSPRO is pointing me in the direction I think I'll go. A very nice guy, Don, advised that their Tach R8585M should be able to read the signal from the Toyota sensor.


One wire to ground, one wire to the sensor, calibrate to the number of teeth on the flywheel, and I'll be done (I hope). Now I just need to figure out where to mount a 3 3/8" gauge...

 

[Creeker]

Creeker,
I just wanted to be clear (since I babble) that engineering at ISSPRO (Bill Carson) indicated that their unit will not work as shipped. Also, the signal output from the Toyota Sensor is TWO wires from the coil, not one. If the sensor can be screwed in closer to the flywheel teeth, it may generate enough voltage to work. I have not removed my sensor to see this and I do not intend investigate the adjustment.

panoramic - thanks for the summary, and I got the gist first time around. My reaction was "Oh s***, and I thought I was done with this...". I'll see if I can voltage input requirements for other gauges.

The Toyota sensor can't be screwed in any tighter, so that isn't an option. Another alternative would be to replace the sensor. Isspro's sensors have imperial threads (3/4" x 16). That would probably necessitate tapping out the existing bell housing. No simple answers.

FWIW, the sensor is easy to get at if your truck is lifted .

 

[Creeker]

<snip>

I am not sure if there is a different unit for 12V pickup versus 24V but someone should be able to see if they are different part numbers. Any takers?

<snip>

I should also note that I actually own a 24-Volt tach from a HJ-61 and a 12-Volt tach from a Aussie 40-series. <snip>

panoramic - I've read that only the light bulb is affected by the truck's voltage.

I like the looks of the stock tachs. Is your only compatibility concern the voltage? Or is something else not working?

 

[panoramic]

Creeker,
A couple updates. Actually both Tachs are 12Volts. And I converted my 12HT from 24 to 12volts. Yes, I can use either of my tachs if/when I get the proper wiring for them but dashboard space is a consideration as well.

Where did you see the information about the OEM Tach's voltage requirements?

Another data point: I just called Nordskog - They make a really nice digital swing tach for diesel with an LED dot arc. Unfortunately, It will not just plug in either - It does NOT require signal cinditioning (They trigger at 1Volt) but it DOES need a frequency divider because they oversimplified the jumpers for the tooth count....

I am thinking about buying an el-cheapo Harbour Frieght gasoline-style tach for $20 and seeing if I can can just condition the signal the way I want. I may just double the frequency so I get an equiv. of 8k instead of 4k and that gives me full needle swing...

Fwiw: I want analog to get a quick reading for things like clutch slippage and
digital numeric readout to run PTO accessories. (Yeah, I want everything!)

 

[panoramic]

Update: I picked up a cheap harbour freight optical tachometer to check what the tooth/pulse count per revolution is. I'll sneak into the garage tonight and check!

I also acquired a Sun brand $30 ignition-based, dashboard tach from PepBoys to experiment.

Creeker, any updates on your side?

 

[Creeker]

Currently looking for a stock tach .

 

[panoramic]

Creeker,
I may have a source for some but you will STILL need to decode which wire is the signal without blowing up the gauge. Sending you a PM...

 

[freebie]

Man you guys could have had the Tiny Tach installed weeks ago and be out wheelin? you can install it in 20 minutes and there's no messing around.
Welcome to Design Technologies and Tiny-Tach, and look in the deisel section.

Cheers

 

[panoramic]

Whatever, dude!
We have already mentioned this unit (and others) in the thread. Of course it doesn't stop us from 'wheelin. Real men shift by engine sound - not a tach! Anyway.... I am doing this research for the coolness of it during non-wheelin days.

Man you guys could have had the Tiny Tach installed weeks ago and be out wheelin? you can install it in 20 minutes and there's no messing around.
Welcome to Design Technologies and Tiny-Tach, and look in the deisel section.

Cheers

 

[BlueHZT60]

Whatever, dude!
We have already mentioned this unit (and others) in the thread. Of course it doesn't stop us from 'wheelin. Real men shift by engine sound - not a tach! Anyway.... I am doing this research for the coolness of it during non-wheelin days.

Wow, I must be a tactless real man

I know ISPRO will work because I have seen it in a 60 with a 12ht. It was installed by Mountain View Motors, Bend, OR if you want to call - just ask about the red diesel 60, they will know it.

IIRC - they glued sensors on the flywheel 180 degrees opposite for the pick up, then it's simple wiring to the dash, calibration and finding a slightly oversized rubber gasket to have it look decent (not stock, but decent).

Herb Peyrol(??) also worked up a special translation-electronic doohicky (listen to me & I'm an engineer to boot), anyway, last I heard, Herb had his 60-hz tach issue planned to work, but I don't know if he actually got it working.

And finally, Rick D. knows exactly how and what works. To bad I boogered my 70-series tach. I believe I still have a 60 series 2h tach laying around - don't know if that will work, and haven't tried it yet.

I look forward to a happy outcome, then I won't be tactless.

Bob

 

[panoramic]

Hi Bob,
Interesting stuff - Thanks!

Gluing magnets on the flywheel probably requires removing the transmission/transfer case and cleaning the flywheel. Also, gluing something to a flywheel doesn't trigger the thoughts of reliability and elegance either. I still *really* like the idea of the OEM sensor install and want to pursue that angle with a aftermarket small gauge or readout.

This Herb Peyrol guy is on the same track as me wrt to a signal conditioner. If you have more detailed contact information or a link to him I would really like to see where he is so I don't duplicate his efforts. Maybe I can collaborate with him....

I have seen some of Rick_D's posts. I will PM him when I have a little time.

Wow, I must be a tactless real man

I know ISPRO will work because I have seen it in a 60 with a 12ht. It was installed by Mountain View Motors, Bend, OR if you want to call - just ask about the red diesel 60, they will know it.

IIRC - they glued sensors on the flywheel 180 degrees opposite for the pick up, then it's simple wiring to the dash, calibration and finding a slightly oversized rubber gasket to have it look decent (not stock, but decent).

Herb Peyrol(??) also worked up a special translation-electronic doohicky (listen to me & I'm an engineer to boot), anyway, last I heard, Herb had his 60-hz tach issue planned to work, but I don't know if he actually got it working.

And finally, Rick D. knows exactly how and what works. To bad I boogered my 70-series tach. I believe I still have a 60 series 2h tach laying around - don't know if that will work, and haven't tried it yet.

I look forward to a happy outcome, then I won't be tactless.

Bob

 

[BinaryDude]

I think i found a way to reuse the original tach flywheel sender with a standard tach:

Universal Diesel Alternator Tachometer Interface

this converts the the flywheel signal into an inductive signal so you can you any 4-6-8 gas tach out there. Now, my tach i just got has a W input choice, but not a flywheel input. I think i will be getting this converter when i get my HJ in...

 

[astr]

Update: I picked up a cheap harbour freight optical tachometer to check what the tooth/pulse count per revolution is...

I believe that the pickup senses the starter teeth on the flywheel. If that is the case, then you will get one sinesoidal cycle per tooth. If you count the teeth on the flywheel, you will have the conversion factor from Hz to RPM. This will be more accurate than relying on the HF tach.

 

[panoramic]

Ok,
1st: again, I picked up the gas tach so I can experiment with my own conditioning circuit - it will definitely not work 'as is'.
2nd: I just called dakota digital and asked them if our signal will work. They thought it would NOT because the voltage level is too low, but they will confirm and call me back today. I'll let everyone know.

I believe that the pickup senses the starter teeth on the flywheel. If that is the case, then you will get one sinesoidal cycle per tooth. If you count the teeth on the flywheel, you will have the conversion factor from Hz to RPM. This will be more accurate than relying on the HF tach.

I think i found a way to reuse the original tach flywheel sender with a standard tach:

Universal Diesel Alternator Tachometer Interface

this converts the the flywheel signal into an inductive signal so you can you any 4-6-8 gas tach out there. Now, my tach i just got has a W input choice, but not a flywheel input. I think i will be getting this converter when i get my HJ in...

 

[Teebag]

Panoramic,

can you clarify the following:

You are correct: We do NOT have a Fall Effect Sensor (FET).
Our OEM sensor is a simple 500 ohm pickup coil w/ magnet(s) on the flywheel.

I have also read there are magnets in the flywheel, but nothing is visible, have also been told the sensor "counts" the teeth of the flywheel, similar to the ABS toothed gear.

 

[panoramic]

MAJOR UPDATE!

After A LOT of work....

I have engineered a tachometer conditioning unit specifically for the 2H and 12HT. My prototype is pictured below. I have confirmed the accuracy with an external tach and it is dead on. I am still trying to get absolute confirmation whether the flywheel is 108 or 110 teeth, so if you know PLEASE let me know. fwiw: My unit is crystal controlled for absolute accuracy over extreme temperature ranges and is accurate to 1 RPM. It also outputs an analog signal for a needle-style analog tach.

The final box will be much smaller, but this is just for me to play with.

I am going to seek out anyone in my area with a 3B or 12BT and see if I can get some measurements from their tach so that it will work for them too.

- Eric

 

[integrin]

just coming out of hibernation here, but i wanted to chime in and say we hooked up panoramic's signal conditioner and analog/digital gauges to my 12HT's dangling receiver tonight. it works like a charm. the reading is accurate and responsive without seeming twitchy.

as much as i dig the digital display, i think i like the idea of combining panoramic's signal conditioner with my existing FJ60 gauge. i'll donate my tach to the cause after the weekend if we don't locate another for testing sooner. i'll also be pulling the gauge on my other truck (24V HJ60 with 2H) to grab the part number.

anyway, it was nice to finally put some numbers to the engine notes i've grown so familiar with. thanks for your work on this, panoramic, Creeker, etc!

 

[BitterSweet61]

Trying to work out the same problem on my fj60 to 12ht conversion but I got lost around the same time that AGeekBoy did. Wondering if you could dumb it down for me. I have the signal wire off the bell housing and my fj60 tach in the dash. What do I need to do to get it all working?