3B Stock tacho not working, and wiring issue (photos)

[beejay42]

No response on this thread yet so I thought instead of further threadjacking it I would start a new one.

Question is- the PO I bought this from had recently put a tacho back in- as it had been removed at some point by a PPO.
He has plugged it in- the light works in it, but the tacho itself doesn't work.
The question is, how and where does the stock tacho pick up? Alternator, water pump??

(as seen below- there are a few things going on here electrically- the washer bottle had been removed, and the blower for the heater- both of these are going back in and needing to be wired up)

I've taken a few shots in the engine bay-
so feel free anyone to help answer my Tacho question- or simply make any observations and pointers (I am still learning about this engine).

heres the tacho- I am pretty sure it is a stock one

plugged straight in

this is where I think it is coming out (drivers side)
I have figured out (multimeter) that one of these empty sockets is for the window washer (that had also been removed) and don't know what the other one is.

wires go on to the alternator and beyond

one wire going down to an earth(??) on the block, another wire with it connected to nothing

remaining wired going over...

to here- where there is also an empty socket...

other than that,
on the passenger side there are a few more empty sockets

one of the small ones I think (?) is for the blower (that was also removed), the others I don't know.

So,
don't hold back if anyone can shed some light on the tacho issue, or just offer any general advice or observations on some of the visiable empty sockets and loose wires (or anything else for that matter)
Cheers,
Hans.

 

[brisveganbj42]

hey Hans,

The tacho pickup is on the drivers side of the bellhousing, probably up near the top..

the tacho is known to go due to the sender end getting covered with crap. on my previous Bj42 the tacho would work occasionally. You could toggle the lights on and off a bit and it would work for a while.. then it would just quit. I got a different sender with no luck.

the tacho on my current bj42 works fine.. i think it ended up being the actual tacho itself.

i can tell you now the sender from a 2h wont fit.

 

[brisveganbj42]

i thought this was the low pressure cut off switch but i think i learnt on here its the actually the oil pressure sender.

there should be another sender/switch to the left of that with similar plugs. this is the low oil pressure cutoff. if you have an edic it'll tell it to shut off the fuel.

in this photo i THINK the one missing is the temp sender.. but i am probly wrong.. iknow one is the temp sender..

anyway.. hope thats helped a bit..

 

[beejay42]

Thanks Andrew-
that has helped a lot.

I'll try to find the tacho sender in the light- do you recall how many wires went to it? One like my oil pressure sender, or two like my temp sender?

as my oil pressure gauge works- you are probably right with that being the oil pressure sender-

and, as I don't have an EDIC- I suppose that loose wire could be meant to go to the oil pressure cut off? not much need for it without an EDIC? or is it a loose earth...?
(electrical illiterate here)

with this one

as my temperature gauge works too I assume that the connected one is the temp sender- begging the question of what the other one is?


and with the alternator

is that terminal below the 'E' meant to be connected to anything?

One thing I haven't figured out (among many) is that my ammeter doesn't move off the middle-
here it is with the engine running

cheers.

 

[BillyGHusk]

Someone stated in a thread of mine the other day that the other sensor in the Thermostat housing was for the glow plug timing system....my rig is set with a manual glow so I have no idea....

The front sensor was my temp gauge as well.

Hope that helps in some small way.

 

[beejay42]

thanks Billy- that would make sense if it is correct- mine too is a manual glow system. So maybe thats another thing I don't have to concern myself with. Cheers,

 

[Moe R]

One thing I haven't figured out (among many) is that my ammeter doesn't move off the middle-
here it is with the engine running


Mine does the same thing. When I start the engine it barley moves and when the engine is running, it dosen't move at all. I put an Autometer ammeter on it and it moves more, but not alot more.

Excuse the funky colors, if I'm not on my home computer I can't get this site to work very well mod help mabe?

 

[beejay42]

Cool colors Moe
it almost goes with my one of my new experimental gear shifter knobs I just made- the one on the left

Interesting about the ammeter...
it would be good to hear from some other 3B'ers to see if this is a common trait/problem. thanks for the post,

 

[Helomech]

The sensor beside the coolant temp sender is a temperature switch that is connected to the glow timer that shuts off the glow plugs once the engine has reached a certain temperature. Looks like it's not required with your setup.

The tach sender is a magnetic pickup that is triggered by the teeth on the flywheel. You can unthread it from the bellhousing to check it's conditon. Mine has a round plug for the connector, not sure if yours will.

 

[brisveganbj42]

The tach sender is a magnetic pickup that is triggered by the teeth on the flywheel. You can unthread it from the bellhousing to check it's conditon. Mine has a round plug for the connector, not sure if yours will.

same with mine.. i think i recall it connecting over the gearbox..

both of my ammeters (on the 2 bj42's ive had) have never really worked.. ive got another one (aftermarket) but have never hooked it up.

 

[beejay42]

Thanks Mike and Andrew-

I'll try to find the tach sender tomorrow arv and see if it is connected.
If it is, I suppose the there is something wrong with the pickup- and if it isn't then I guess the fun starts trying to find the right wiring...
we'll see.

Its true- it appears my setup as is has no need of the temperature switch-

pity about the ammeters- oh well, at least it is a common problem and not just me.

So I think thats most of my queeries answered.
many thanks.

Hans.

 

[cruiser_guy]

Check the sender on the bellhousing. It should have about 400 ohms across the wires if it's good. Often the wires will break especially when you get the clutch done as they forget to disconnect them.

As for the ammeter, on my '76 FJ55, which has the stock '55 gauges and a 3B powering it, the ammeter actually has quite a bit of movement most all the time.

 

[beejay42]

Bummer-
just checked and I have no tacho sensor/sender in the bellhousing- just a hole (as pictured at the end of this thread in a photo posted by Exmodlad).

So, I guess I will have to try to source one. No real urgency on it- it would just be nice to have working.

Thanks for the help all,
Hans.

 

[brisveganbj42]

I'm pretty sure I have a spare tacho sender for the 3b Hans.

If you have trouble finding one let me know and I can sell it to you, post it down.

I'll have a dig around my parts bin on the weekend and confirm i've still got one.

 

[beejay42]

Cheers Andrew,
let me know if you come across it-
The only wreckers I know so far down here is Halls4x4...
far from cheap as far as I can tell (for me at least) and frankly I'd rather keep it in the 40family so to speak.
If you do have one and want to pass it on- then at least my $ sent to you can go straight back into your rig.

btw, I picked up the plastic ducting I needed for the heater, the valve for the coolant lines, and a pile of missing dash switches, among other things this evening- (thanks again Hamish).
Now I just need to get this dash panel painted and I am almost ready to put it all back together.
I am going to try to get the blower, the ducting and the heater core in tomorrow, and whatever else I can fit in.

 

[lostmarbles]

...Interesting about the ammeter...
it would be good to hear from some other 3B'ers to see if this is a common trait/problem. thanks for the post,

Yes. Our ammeters don't move much Hans. This appears to be an "ex-factory feature" - that could be confined to the Australia/NZ market models. (- I'm not sure whether USA-market vehicles were similarly affected.)

About all I see with mine is "regular twitching" when my hazard lights are on. Or a "a single twitch" when I flick on my headlights.

(It has been like this ever since I bought it in Perth back in September 1981.)

 

[hes21]

For my Fj and the limited expereince I have had in my Bj the ammeter is really only good for determining that something is really wrong. I only see it move when i've left something running with the engine off and it starts heavily charging. In my FJ I was also having shorting problems with my LPG system that was blowing the engine fuse. I put in a larger engine fuse and then kept an eye on the ammeter. When the short occured the ammeter would swing extremely to the right.

Good luck with getting all the heating installed!

Hamish

 

[Madeira]

Hi everyone, recovering this old thread as I am attempting to run a factory tacho with the original tach sender. My truck didn´t come with it. I recently replaced the clutch and had the sender installed in the bellhousing. Could someone please explain how the wiring goes?

 

[wormfood]

the back of the tach should have 5 wires
red
black
white/black
red/green
black/yellow

black and red are power and ground for the tach electronics and should wire in to have power like the other gauges; when the key is in the on position
red/green and white/black are for the light, so wired to the light switch like the other gauges
black/yellow is the signal from the sensor and should just be a wire straight from the sensor

the sensor should have two wires, one to the gauge and one to ground.

 

[graymudder]

the back of the tach should have 5 wires
red
black
white/black
red/green
black/yellow

black and red are power and ground for the tach electronics and should wire in to have power like the other gauges; when the key is in the on position
red/green and white/black are for the light, so wired to the light switch like the other gauges
black/yellow is the signal from the sensor and should just be a wire straight from the sensor

the sensor should have two wires, one to the gauge and one to ground.

I could swear that on my manual I see the tachometer sending unit attached to the pump...