figure this out!!
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Cross-Country
Joined: Aug 2005
Posts: 53
Likes: 0
figure this out!!
With the headlights on, when I turn the turn signal on the tachometer pegs back and forth as the flasher turns on and off. It doesn't do it with the headlights off. Also, when it is cold outside, the tachometer doesn't work. It sticks in one spot. but it only does this when it is cold outside.
These arent anything important, but I would like to fix it.
Any help will be appriciated.
These arent anything important, but I would like to fix it.
Any help will be appriciated.
Post Fiend
Joined: Jul 2004
Posts: 8,786
Likes: 28
From: Northern California
Fellro has a good suggestion.
I would also check the connector to the cluster. Make sure the wires are not rubbing together at the connector, and make sure the pins and connector are seatted correctly in the cluster. The pins are close together and could be moving about touching other contacts they are not supposed to. Also check the ground to the cluster. Bad grounds can cause all sorts of weird problems as you describe.
As for the tach, you could try and put a little drop of oil such as WD-40 on the shaft that goes inside the tach that the needle attaches to. If you put too much you could blow, or short out the tach though so be careful.
I would also check the connector to the cluster. Make sure the wires are not rubbing together at the connector, and make sure the pins and connector are seatted correctly in the cluster. The pins are close together and could be moving about touching other contacts they are not supposed to. Also check the ground to the cluster. Bad grounds can cause all sorts of weird problems as you describe.
As for the tach, you could try and put a little drop of oil such as WD-40 on the shaft that goes inside the tach that the needle attaches to. If you put too much you could blow, or short out the tach though so be careful.
Fleet Owner
Joined: Sep 2005
Posts: 28,609
Likes: 18
From: Lake Tahoe, Nevada
The tach not working when cold is most likely a mechanical problem in the tach.
Does the tach act up using the right and left signals?
I'm thinking that your printed circuit is not grounded properly so the signal is feeding back through the ground side of the tach. Are the signal idicator lights on the dash dim? I would expect so if I'm right about the ground.
As Piffery says, ground the firewall to the block and chassis. But also make certain that the printed circuit has a ground if that doesn't cure it.
Does the tach act up using the right and left signals?
I'm thinking that your printed circuit is not grounded properly so the signal is feeding back through the ground side of the tach. Are the signal idicator lights on the dash dim? I would expect so if I'm right about the ground.
As Piffery says, ground the firewall to the block and chassis. But also make certain that the printed circuit has a ground if that doesn't cure it.
Posting Guru
Joined: Jun 2004
Posts: 1,635
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From: Niceville, FL.
The mounting screw for the tab of the instrument voltage regulator is a good place to connect an external ground wire from the metal dash panel support or firewall.
As Bdox says, it can clear up lots of strange problems with gauges and lamps.
As Bdox says, it can clear up lots of strange problems with gauges and lamps.
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Cross-Country
Joined: Aug 2005
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My truck is an 86. Yes, the tach pegs with both left and right turn signals. And with the sticky tach, if I drive around for a while with the heater on, when the cab warms up the tach starts working again. Maybe it needs lubed up?
Thanks for the input.
Thanks for the input.
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Post Fiend
Joined: Jul 2004
Posts: 8,786
Likes: 28
From: Northern California
I was grasping at straws at the lube part, a sticky return spring I imagine.
A dry lube that doesn't collect dirt perhaps.
A seperate ground wire from the voltage regulator, hold down screw, to the dash frame metal, is a great idea. may do that to mine.
A dry lube that doesn't collect dirt perhaps.
A seperate ground wire from the voltage regulator, hold down screw, to the dash frame metal, is a great idea. may do that to mine.
Post Fiend
Joined: Jul 2004
Posts: 8,786
Likes: 28
From: Northern California
Originally Posted by Bdox
Surely that tach is a jeweled pivot, like in a Rolex.
Seriously though, I don't think it should be lubed. Just clean.
Seriously though, I don't think it should be lubed. Just clean.
You're right it shouldn't be lubed, but if it doesn't work and/or it's sticky, it wouldn't hurt it much if it was. IMO.
Hmmmm... It acts like to me that if the tach was lubed at the manufacturer/ or if somebody sprayed lube into it before, that it is getting cold and becoming sticky, or that it's worn out and has a flat spot, and when it heats up the expansion releases it. I can't see much dust and dirt getting into the tach, in the cluster.
If you lube it, it could make it work like new, it could also blow it up, and finish it off, or it will work the same as it does now. Be prepared for any eventuality, like that.
If only you could open the thing up, but you can't. It's a sealed unit.
What he really needs is a new tach, all being proper etc...
Posting Guru
Joined: Jun 2004
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From: Niceville, FL.
That problem too, may clear up once the ground(?) problem is resolved since the tach needs a good ground reference to work. I wouldn't go squirting anything in the tach until the other issues are resolved and all the tach wiring has been checked out.
Post Fiend
Joined: Jul 2004
Posts: 8,786
Likes: 28
From: Northern California
Originally Posted by Piffery1
That problem too, may clear up once the ground(?) problem is resolved since the tach needs a good ground reference to work. I wouldn't go squirting anything in the tach until the other issues are resolved and all the tach wiring has been checked out.
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