Sv21 Camry with 3sge & lts now adding a tacho gauge cluster.. finding the right wire?

[Rhyno]

Hey guys,

I have an SV21 Camry with a 3sge in it and a microtech lt10s. When I had the microtech wired up the car was running the pov spec gauge cluster with the huge analog clock. I have just sourced and fitted a cluster with a tacho that revs to 8 thousand, (just enough ) and everything works but the tacho, haha

Now when the auto elec fitted the microtech he showed me a wire with "tacho output" on it coming from the lt10s, and if I ever got a tacho to connect it to there...

So after some hunting around under the dash with a multimeter, reading through the wiring diagrams in my Gregorys manual for the Celica and Camry, and searching the interwebs, I have come up a bit blank...

There is a bit of info on the net on hooking up aftermarket or monster tacho's up to the 3sfe Celica/Camry's, but nothing on getting a standalone ecu to work with the standard tacho - all I can think it maybe looking at a write up on someone installing a standalone ecu into a Celica, and what wire they used...

Any light anyone could shed on this issue would be greatly appreciated.

Cheers,

Ryan

[jonathan yee]

I think the microtech has a spec tach out wire, look at the mtech diags find that wire.

Also generally aftermarket tachs just use either the neg or pos signal from the ign coil.

Then add power and earth.

[Rhyno]

Hi Jonathan thanks for your input,

Yes the microtech lt10s does have a tach output wire, found that no worries - If it was an aftermarket Tacho it would be no problem, but I am using a gauge cluster from another SV21 Camry that has a tacho - the problem is I don't know which wire to use to connect to the cluster as the auto elec I took it to didn't hook it up as there was no tacho at that time.

All the diagrams in the Gregorys manual are misleading (at least to me!) and I can't find any info on the interwebs.

Everything else in the cluster works, park brake, highbeam etc etc

Kind regards,

Ryan

[RA35GT]

Assuming you don't have pinouts for the tacho dash cluster?

Can you compare the two dash connectors for the extra tacho wire?

Can you dissassemble the tacho cluster itself to see which wire it gets it's signal from?

Not sure where the original tacho signal comes from on sv21's, i imagine either the ignitor or directly from the coil -. You may need to use a booster depending on the output of the microtech.

[jonathan yee]

ah, mis understood. i have a manual at home which covers a fair whack of toyota's. i'll hunt thru it to see if it has the info.

just to verify what year camry wagon? orig 3sfe engine?

[Rhyno]

Hi RA35,

Yeah no pin outs for dash cluster - it is an old Camry after all

I can compare the two, not sure what I should be looking for? There is actually 3 plugs that connects into the back of the cluster...

I tried tracing the wires from the tacho to the plugs, but was not the easiest, may just have to try and try again.

All good Jonathan, Its the pov spec CS Sv21, 1991 model. The cluster is out of an 88 I believe, I think CS as well. Both have the 3sfe engine and manual.

Thanks for your input guys

[Rhyno]

Hey agian,

Started installing a car alarm today and had to pull the dash apart to run various wires, so I thought I would have another crack at getting this tacho working. For the last three months I have just been driving by ear (and the shit line bar output on the microtech hand controller).

So I thought I would bite the bullet and pulled the cluster out and disassembled the cluster, and removed the tacho. Looking at the rear of it there is three
input wires.

So using a multimeter I found the only possible connection for the microtech output was the bottom terminal. Unfortuantly I didnt take a photo of the tach when I had it out but I took some photos of the cluster for reference.

1st one is a shot of the back of the cluster
2nd is a close up of the tacho connections, the 2 gold coloured screws mount the tacho to the cluster, and the three grey screws to the left are the connections for the tacho. I then traced the Ign- wire to the plug and connected the microtech to this terminal and had no change.

Thinking that there may be a power supply issue I checked for power on the tacho and had 12v+ across the Ign + and Earth terminals, and also 12v+ across the Ign + and Ign - terminals.

Thinking something was up I did some googling and came up with these links:
http://forum.n12turbo.com/viewtopic....0e8f282f57b0de

I then found a link to a tacho booster linked by The Witzl and I think this is what I need to build to get the lot working: http://www.toymods.org.au/forums/tec...o-adaptor.html

Interested in your thoughts and opinions.

Kind regards,

Ryan

[4th surf]

I did this years ago (on a 92 Corona wagon) but can't remember which wiring plug I had to fit the extra wire into.

Anyhow stock as RA35 correctly partly guessed the tacho signal is from the ignitor and is generally a black wire.

[dumbass]

that ig- wire is correct
but im 99% sure u need a tacho booster
i can piss stronger than the tacho signal on a microwreck

[Rhyno]

Hey guys,

Thanks for your input.

Did some more searching last night and confirmed that the Microtech uses a +5V Squarewave output for its tacho signal and the older toyota's use a collapsing negative wave from the coil.

Time to build an adaptor

[Zammo]

or just but one they not expensive

[Rhyno]

Built one last night for $1.36, using the Witzl's external guide: http://www.toymods.org.au/forums/tec...o-booster.html

Will test it tonight

[Zammo]

i take it you had the bitz laying around cause $1.36 is cheap like crack whore cheap you sure you wanna put that in a toyota

[Rhyno]

Yeah raped an 22 year old Ovlov 240 I have been parting out. The converter worked for all of about 5 seconds and died Freaking out I checked all my inputs and outputs, and found everything aok. So I figured I must have fried the transistor, and set about building a second one with Identical parts to what the Witzl used (first one had a slightly different transistor), with again the same result

So I then cracked open the relay again and hard wired it to the battery and had SFA. Haha so off to buy a new relay today and hope all is well. What you get for being cheap

Oh well I was going to need a Tach adaptor for the 'Rona anyway, so now I have one for each car haha

[Zammo]

What you get for being Crack Whore cheap

there fixed for ya