Tachometer

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blackstack
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Tachometer

Post by blackstack »

I have a swiss 710m.

Electronic ignition.

I installed a VDO tachometer that does not work properly.

The tach responds to different engine speeds but never goes past the 500 rpm mark. To me it looks like it is reading a tenth of what it should read.

I have checked the dip switches and wiggled and/or cleaned all the connections to no avail.

Any ideas?

Thanks
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pcolette
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Post by pcolette »

I found that some of the VDO tachs have the dip switches in reverse order. You are probably set for 8 cylinders. Instead of ON/OFF/OFF try OFF/OFF/ON. This worked for me when I had the same issues you described.

Paul
Paul C.
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'73 Swiss 710M
'89 Puch 230GE
krick3tt
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tachometer

Post by krick3tt »

I bought a VDO tach and had to get a resister to make it operate properly, from 24v down to 12v. A friend sent me a step by step pictorial installation guide. The tach worked for awhile but would flop back and forth from 500 to 6000 rpm's I had to send it back. Now the one I have works well, I used the same guide that my friend sent both times.
It makes a difference where you tap off the input from the electronics for the dist., at least it did for me.

I also bought an electronic speedometer that died after 2000 miles. Not real happy with VDO stuff. I put the mechanical speedo back in and although it is a bit off because of the 33 inch tyres it still reads and works. I just have to do a bit of math sometimes to get the 8% discrepancy for the tyres. Figuring MPH from KM is no problem, just multiply by 6 for a reasonable guess.
Jim LaGuardia
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Post by Jim LaGuardia »

That 12v VDO tach is a pile of crap :shock:
Spend the extra few bucks and get a 24v one from aircraft spruce.
Every 12v VDO tach I have installed or adjusted are not accurate.
They are usually 300-500 rpm off.
Cheers, Jim LaGuardia
http://smg.photobucket.com/albums/v510/Goatwerks/
"Arch Magus of Machines."
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pcolette
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Post by pcolette »

Jim,
Is there one in particular that you recommend from Aircraft Spruce?

Paul
Paul C.
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'73 Swiss 710M
'89 Puch 230GE
blackstack
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Dippy Tach

Post by blackstack »

Hey Paul !!

I reversed the dip switch settings as you suggested and.............IT'S ALIVE !!! I have to laugh because I am dumb as a sack of rocks about electricity ..I compare everything to pipes and valves and waterflow...when it didn't work when we put it in I told my son to switch the dip settings 'cause "the valve must be backwards" and he gave me hell and a bunch of electrical theory..i can't wait to rub it in.!!

I wonder if there is a table comparing speed to rpm in the various gears ..or at least in 5th?

Reads about 600 at idle so am guessing it isn't too far off.

I use a GPS for a speedometer...I was thinking of getting a programmable from VDO but maybe not what with the bad reviews

Thanks again,
Bob Gray
Jim LaGuardia
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Post by Jim LaGuardia »

Good to hear you got it working. It seems that the 12v VDO tach is more responsive/accurate when truck is equiped with Pertronix module VS points.
Here is a lnk to a nice tach/hr meter.
http://www.aircraftspruce.com/catalog/i ... ometer.php
Cheers, Jim LaGuardia
http://smg.photobucket.com/albums/v510/Goatwerks/
"Arch Magus of Machines."
krick3tt
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tachometer

Post by krick3tt »

Looking at the Aircraft Spruce tach specs, there was mention of saving settings. Does power have to be maintained, similar to a radio to save channel settings, for this feature to be effective?

When I remove the battery key all settings on the radio are gone, don't even use them.
Jim LaGuardia
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Post by Jim LaGuardia »

Spec sheet says non volitile memory. So loss of power does not effect settings.
Looks like a nice unit and can handle up to 33 vdc.
Cheers, Jim LaGuardia
http://smg.photobucket.com/albums/v510/Goatwerks/
"Arch Magus of Machines."
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ako
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Re:

Post by ako »

Jim LaGuardia wrote:Good to hear you got it working. It seems that the 12v VDO tach is more responsive/accurate when truck is equiped with Pertronix module VS points.
Here is a lnk to a nice tach/hr meter.
http://www.aircraftspruce.com/catalog/i ... ometer.php
Jim,

The link you provided is a 404. Could you please confirm which tacho you recommend out of this lot?

http://www.aircraftspruce.com/menus/in/tachometers.html

Thanks
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TechMOGogy
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Re: Tachometer

Post by TechMOGogy »

72 Pathfinder | 75 710M 2.7i | 96 350GDT Worker
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ako
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Re: Tachometer

Post by ako »

TechMOGogy wrote:Just use this one from SAV
http://www.pinzgauer.com/showdetails.ph ... no=SAV1404
I saw that one, but from above Jim said this :
Jim LaGuardia wrote:That 12v VDO tach is a pile of crap :shock:
Spend the extra few bucks and get a 24v one from aircraft spruce.
Every 12v VDO tach I have installed or adjusted are not accurate.
They are usually 300-500 rpm off.
I figured I would listen to someone who knows a lot more than me. :mrgreen:
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Re: Tachometer

Post by Stekay »

http://www.issprogauges.com/Classic-0-5 ... r85090.htm

It's nice to have a big easy to read face that's not over scaled. 5000 RPM and just twist the signal wire around the coil wire.
'76 710K
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Re: Tachometer

Post by pinzinator »

Has anyone seen a 24 volt digital tach?
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rmel
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Re: Tachometer

Post by rmel »

I have a 50mm digital VDO 12V, but they do have a line 12/24v but they are 85mm.


http://www.vdo-instruments.com/instrume ... eters.html
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