HDJ81 looking for VSS signal Mechanical Speedometer (1 Viewer)

[thedoctorhunting]

I have a 1991 HDJ81 with a mechanical speedometer ie. it has a speedometer cable - mechanical speedo (not a VSS - Electronic speedometer).
The vehicle has a 5 speed manual transmission, and full locker assembly.
I am trying to put cruise control onto the vehicle and am therefore looking to put a VSS in series with the exisiting speedo cable or to locate a possible VSS signal that may already be on the vehicle.

I have searched the posts for a VSS signal for my vehicle and the existing posts indicate if such a signal was present it would be behind the glove box and the forum gives likely locations for the possible signal wire. I assume that since I have the mechanical speedometer cable and no VSS at the transfer case that even though the wires indicated on the forum may be present .....they will have no VSS signal.

In any case I did take a Voltmeter and tried to get a signal from the possible wires behind the glove box while the vehicle was moving, and I also cut the likely wires and found the speedometer still worked (it should since it is mechanical)......so I assume that there is no VSS signal on any of the wires behind the glove box?

I have been told that the US issue early 80's had cruise control with mechanical speedos and that the VSS signal was taken from the rear of the speedometer guage and that the signal was electrical and not mechanical? Does anyone know if this is true, and if so were on the speedometer was the signal taken etc.

Failing this possible location for taking a VSS signal for cruise control, I am thinking about getting a VSS sensor from:
Magnetic Sensors Corporation, Quality Sensor Products Since 1983

Issue with this is that I will likely have to cut my cable and somehow splice the VSS into the existing Speedo cable...anyone have any experience with this.......such as possible problems with gunk getting in or cable sticking etc.?


Thanks in advance for any help

 

[CJF]

I have been told that the US issue early 80's had cruise control with mechanical speedos and that the VSS signal was taken from the rear of the speedometer guage and that the signal was electrical and not mechanical? Does anyone know if this is true...

Not true.

91-92 80 series have a VSS inline with the speedo cable right where it plugs into the transfer case. The sole purpose of this sensor is the cruise control; you can even remove this sensor and still plug the speedo cable right into the t-case.

If you have the same AWD transfer case as a US 80, I'd guess that it's highly likely that this sensor would fit right in, although of course you'll probably have to wire it on your own.

Curtis

 

[Downey]

Here's the deal:
The VSS signal that is built into your 80 was probably generated on a printed circuit board on the back of the spedo. I'm not an FJ80 guy, so have not looked up what singal was generated, but probably it is a 4 pulse square wave (DC) used for computor/emissions operation. Electronic Spedos can be anything the manufacturer wants them to be with reguard to pulse count and polarity. Most require a 4 pulse sine wave (AC), or they are adjustable??? The no-brainer would be if you could find one that takes 2 pulse DC or 4 pulse AC, then you could simply use one of our spedo cable driven VSS's that already has the Toyota thread and drive tangs, simple bolt-in!!!

 

[thedoctorhunting]

So if I understand it correctly, the 1991, 92 Model 80's, that had cruise control, had an in line VSS that mounted to the speedometer housing on one side, and then had the speedo cable plugged in on the other side?
My housing has M22 X 1.5 male thread and my speedo cable has M 22 X 1.5 female coupler......the VSS would then match these,and have the proper tangs for the speedo cable to mesh, and like CJF has said " you can even remove this sensor and still plug the speedo cable right into the t-case".

This VSS would likely have two wires, one for 12 V Positive in, and one for 12V square wave (analog) out?

Is the pulse frequency of this VSS 2 pulses/revolution?

Does anyone have a part number or spec's.

 

[CJF]

So if I understand it correctly, the 1991, 92 Model 80's, that had cruise control, had an in line VSS that mounted to the speedometer housing on one side, and then had the speedo cable plugged in on the other side?

Correct.

My housing has M22 X 1.5 male thread and my speedo cable has M 22 X 1.5 female coupler......the VSS would then match these,

Sounds right; I haven't looked at mine that closely.

and have the proper tangs for the speedo cable to mesh, and like CJF has said " you can even remove this sensor and still plug the speedo cable right into the t-case".

To clarify what I said earlier, the speedo cable would screw right to the actual speedo housing, which is held into the t-case by a little metal tab.

This VSS would likely have two wires, one for 12 V Positive in, and one for 12V square wave (analog) out?

Is the pulse frequency of this VSS 2 pulses/revolution?

Does anyone have a part number or spec's.

For some reason 4 pulses per rev. comes to mind, but don't quote me on that.

Sorry, don't know a part number.

Curtis

P.S. More backstory: My cruise control went out a few years ago, and I tracked it to a bad speed sensor. Getting it unplugged was a pain, because the connector goes way up over the tranny before connecting to the wiring harness. So, while waiting for the new part, I just connected the cable directly to the speedo as described above; it connected the same way as if the sensor was inline, except just one connection rather than two (like joining multiple garden hoses together), and the speed gauge in the dash worked as normal. If you go this route, there *is* one other part you need: it's a little key/tab that fits either between the speedo cable and sensor, or sensor and speedo (can't remember which). It's just a $2 part that lets the sensor output lock into the speedo cable; I lost mine whan I had the old sensor out and had to order another one.

If you have a friendly dealer parts guy who will let you look at the parts schematics, this will all be much clearer.

 

[JPHockerAZ]

While I was researching which tranny I wanted for my diesel swap I noticed that the 5 speed 80's did not come with cruise control anywhere.

I like cruise control so i began reasearching how to adapt it in to a 5 speed. So far what I have found out is that the early us fj80's had a VSS attached whereas the later us FZJ80's cruise control ran off of the ECT ECU. The Part Numbers and functions for the cruise control ECU are different on the fj80 and fzj80.

SO my guess at this point is that it can be done to a 5 speed with the early VSS and the Early cruise control ECU.

P/N's for reference
Early VSS: 88261-60010
Early cruise control ECU: 88240-60050

I am sure a few other parts are needed but I wont be sure until I dive into this project myself.

Good Luck and post progress!

EDIT: The ECU requires signals from things like the brake lights, neutral start switch, all signals from the cruise control switch, and the throttle position sensor. I dont know if you planned on using the ecu and building a harness from scratch, but it seems like a donor fj80 rig would make this project easier.

 

[thedoctorhunting]

Ok.........so I purchased a "Used" Cruise Control sensor which is as CJF explained a direct bolt in on my transfer case.
The sensor has M22 X 1.5 threaded male and female ends, and comes with a "tang" that allows the sensor to mesh with the speedo pickup coming off of the transfer.......the speedo cable screws onto the other end.
My vehicle did not have a wiring harness for this sensor to plug into, and I have not been able to locate a wiring diagram for the sensor and so now I am faced with having to sort out the wiring hookup for the sensor? The sensor has three wires going into a sealed electronics bundle within the sensor, the wires are Black, Yellow and Red. I have tried putting an OHM meter across the wires, and I am now guessing that the wiring convention is:
Black....ground
Red ....12V Positive...keyed to ignition
Yellow...12V Positive modified pulse out to cruise control, probably a sine wave? and 4 pulses per revolution.

I tried putting the sensor on a bench and attaching the wires as above, and then trying to measure the voltage across the yellow and red (AC voltage) while running the sensor with an electric drill....all I got was a constant 12Volts with no voltage fluctuation.........maybe this used sensor is fried, or maybe I have the wiring screwed up, I do not have access to an occiloscope, also as the sensor is slowly rotated there is no resistance change across the yellow and red?
Incidentally this sensor is still available from Toyota and new is ~ $100......I likely should have purchased a new one?

Can anyone verify the wiring, or if you have a 91, 92 model 80 with this sensor can you tell me which wire has 12V keyed to the ignition, and which is ground?
I have tried running the yellow wire into a Rostra Global cruise control module, and the module does not respond?

Thanks for the help

 

[JPHockerAZ]

are you talking about the speed sensor that mounts to a 91 or 92?

If so the wires should be:

Black: 12v
Green/Red: sensor for ECU
White/Black: ground

hope that helps

 

[CJF]

Bench test from the FSM:

Connect terminal 1 to the positive side of the battery. Connect terminal 3 to the negative side of the battery. Check that there is continuity four times per revolution of the shaft between terminal 2 and the negative side of the battery.

Now, without the ability to post pic's, how am I going to communicate to you which terminal is which when all the FSM shows is an abstract outline of the connector?

Here goes: The way they have the connector oriented, It looks there are two terminals inline horizontally, and then one between and beneath those two. Like this:

2 1
.3

There is no mention of wire colors.

Keep us posted,

Curtis

 

[S24AGE20V]

I know this thread is somewhat ancient, but thought I would resurrect it due to the fact that Toyota has decided to discontinue the 91-93 Cruise VSS for the FJ80s and FJ81s.
I am sure there are owners out there that have sensors that have died and would still like to use their factory cruise control!

Although NOT an owner of a Land Cruiser, I have such a sensor in my Toyota conversion Lotus Europa so that I get the VVT function.

Unfortunately, since Toyota stopped making/selling replacements, I found myself needing to somehow repair my dead "packaging study" unit so I could use it.

I disassembled the VSS and removed the plastic sensor module from the zinc die-cast speedo VSS housing and confirmed it was indeed kaput. No signal on the Yellow sensor wire when Red was tied to 12V and Black wire to Ground looking at the signal from Yellow to Black when rotating the sensor magnet wheel. In fact, trying other combinations gave nothing as well, and it had inifinte resistance power to ground.

So I removed the potting from the plastic sensor housing and cleaned it out. There is a thickfilm module in there you need to take out plus the retention molded-in supports.
Be careful when removing the wiring and molded insulator, you will need it again! I used a Dremel tool for all this, plus dental picks.

Next come what to replace it with that will give the proper 0-12V square-wave output.

I found a site called www.machtach.com that sells good D-I-Y machine tachometers. A gentleman by the name of Henry Arnold sells these, plus various parts for different types of input sensors to interface to them.

I chose his "Gear Tooth Sensor" kit, which comes with the sensor (Allegro) plus a pair of bypass capacitors and a small circuit board. These parts are thru-hole design.

You will need a 1/8W or 1/4W 1K Ohm resistor to complete it plus some soft potting compound.

With a little work you can fit the gear-tooth sensor to one side of the board, the components on the other side and solder up your wiring and fit it into the die-cast case.

Be sure to test this if you have to press parts around to fit (vertically) and make sure you don't break connections or make any shorts.

If you get a 0-12V out, then you are good and can pot the board into place. Replace the cover (I made a thin gasket and also used di-electric grease on the module and then tested it again. If all is good, you are done!

The Gear Tooth Sensor kit from MachTach is about $16.00 plus S&H.

Contact Henry Arnold directly for details.

I did speak with him and if there is enough interest he might make a surface mount version board, maybe even with the resistor and caps already soldered onto it so all you have to do is install the sensor and wiring. If so, I would expect that version to cost a little more, but its then VERY easy to put in place and pot. And a far cry from a retail $175.00 unit that you cannot get any more.

Hope this information give hope and new life to Landcruisers with dead cruise VSS units so you can get your cruise control operational again.

H. Dozier

BTW.....Mods, if you feel this is worthy of its own thread, feel free to create one and move this post.

 

[Sarmajor]

You can buy the speed sensor that mounts on the LHS of the transfer case tail housing where the speedo drive is fitted from Slee. It is used in many Asian vehicle types. I have a spare in my tool box that came off an Isuzu Big Horn.

On my 92 HDJ81 there is no speedo cable, it is all electronic.
It is automatic with cruise control.
Having said that I know mine was built around August 92 when production was being geared up for the 24 valve diesel vehicles with the bigger brakes (which I have).
Toyota fit cruise control on the 5spd manual hiluxes so it can be done.


Sarmajor

 

[S24AGE20V]

If possible, could you post a link to that specific speed sensor for the forum members to go to and look and see if it fits their application?
For myself, having repaired mine, I don't need to worry. I doubt the Allegro part, having an operating temperature range of -40ºC to 150ºC will ever fail in my application, so no need ever to worry about another failure.
But others out there from posts I read while researching sensors and where to get them leads me to believe they might benefit.

H. Dozier

 

[Sarmajor]

Upon rereading this topic I believe that the sensor you are looking for is different to the one I have.
Here is the link to the Marlin Crawler sensor. I believe that it is for the electronic speedo system in 92+ 80 Series.
Vehicle Speed Sensor, MCI | Marlin Crawler, Inc.


Sarmajor