Classic Mustangs List Archive

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Mail From: (email redacted) (Erik Olson)

I had the same thing happen. When I replaced the instrument voltage
transformer all the problems went away.

Erik

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Mail From: (email redacted) ((email redacted))

In a message dated Fri, 15 Jun 2001 11:40:22 PM Eastern Daylight Time, "Dr. Paul R. Sawyer" <(email redacted)> writes:

<< Hello all--

I have a interesting occurrence in my 66 GT coupe (289-4V, automatic). As I was driving today on the highway, I noticed that the needle on my oil pressure gauge would stay about 3/4 of the way across and every now and then would jump up, and sometimes off of the scale. It would slowly drop back to "normal" and then stay more of less put until it jumped again in about 2-3
minutes. The temp gauge never moved.

My gas gauge is doing the same thing. I had to replace the tank, line and sending unit about two weeks ago and since then, the gas needle jumps too. The sending unit was a new FoMoCo unit, so I hope it isn't flaky. Before I swapped the tank and unit, my needle stayed rock solid. I don't think that the old tank had baffles, but, frankly I don't know.

Any and all help is appreciated. Thanks!

--Paul

Sounds like a loose ground wire somewhere..

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Mail From: (email redacted) (Cliff Koch)


> I have a interesting occurrence in my 66 GT coupe (289-4V, automatic). As I
> was driving today on the highway, I noticed that the needle on my oil
> pressure gauge would stay about 3/4 of the way across and every now and then
> would jump up, and sometimes off of the scale. It would slowly drop back to
> "normal" and then stay more of less put until it jumped again in about 2-3
> minutes. The temp gauge never moved.
>
> My gas gauge is doing the same thing. I had to replace the tank, line and
> sending unit about two weeks ago and since then, the gas needle jumps too.
> The sending unit was a new FoMoCo unit, so I hope it isn't flaky. Before I
> swapped the tank and unit, my needle stayed rock solid. I don't think that
> the old tank had baffles, but, frankly I don't know.
>
> Any and all help is appreciated. Thanks!

You need a new IVR (Instrument Voltage Regulator, or something like that).
It's a small metal can somewhere on the back of the cluster.

Cliff
--
--------------------------------------------------------------------------
Cliff Koch
(email redacted)

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Mail From: (email redacted) (Rautenberg, Jeff)

> ... I noticed that the needle on my oil pressure gauge would stay about 3/4 of the way across and every now and then would jump up, and sometimes off of the scale.

> You need a new IVR (Instrument Voltage Regulator, or something like that). It's a small metal can somewhere on the back of the cluster.


Instead of buying the $20-$25 part from Mustang vendors, you can buy the equivalent voltage regulator at a Radio Shack or electronics supply shop for about $3. I recently installed one, and it works perfectly. Check out: texasinternet.com/~dsigns/james/Installing%20Gauges.htm for part #'s and directions for installation. It's about 2/3 of the way down the page.

Jeff Rautenberg
'65 Coupe