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Cylinder Head Temp Gauge not working
Posted by: krfjkm ()
Date: March 09, 2019 06:03PM

Have a new to me 66 Corsa and just put an engine that I built in it. It is running really nice! But my cylinder head temp gauge isn’t working.

What are some of the things I should check to make it work?

Thanks in advance!

KRFJKM
Charlotte NC
1965 Corvair Corsa
1966 Corvair Corsa (60 over with an Isky 280)

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Re: Cylinder Head Temp Gauge not working
Posted by: MattNall ()
Date: March 09, 2019 06:16PM

In our FAQ's! gg

[corvaircenter.com]

MODERATOR
Sea Mountain, between Charleston Harbor and Coos Bay! SW Oregon Coast
Click HERE for My Website...Click HERE for My TechPages!
..............................110-PG.................................................Webered-Turbo

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Re: Cylinder Head Temp Gauge not working
Posted by: krfjkm ()
Date: March 09, 2019 06:31PM

I saw that in the FAQ’s but it reads like Greek to me:

Here is what is says:

This is for 65-66 dashes. EM Spyder dashes will be the same except for Wire color / placements

System Check with COLD engine:

1 with key "ON" is gauge.....

Always over 600f = good 12vdc to gauge / but no ground

Rises to over 600f = shorted lead to Thermister / shorted T-M.

Needle moved but under 200f = gauge funtioning / open circuit to thermister / T-M bad


Thermister / wiring checks

2 wire plug behind dash / Black with light green stripe should read 4,000-6,000 ohms to GROUND

High Temp lead from T-M should read 4-6k ohms

Thermister should read 4-6k ohms

Gauge Checks

With Dash Harness unplugged:

Black / lt Green wire to dash [ 2nd pin in from row across from open hole] to Black / Purple wire in plug [ 2nd pin over from empty hole]
should read 50 ohms [ gauge good ]

with dash harness pugged in / key ON and T-M disconnected you should see 10 VDC clear
back to T-M.

KRFJKM
Charlotte NC
1965 Corvair Corsa
1966 Corvair Corsa (60 over with an Isky 280)



Edited 1 time(s). Last edit at 03/09/2019 07:49PM by MattNall.

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Re: Cylinder Head Temp Gauge not working
Posted by: TerribleTed ()
Date: March 09, 2019 06:51PM

Looks very straight forward to me. Follow the instructions step by step including getting your ohm meter out to check the resistances if necessary. If you are unfamiliar with volt/ohm meters and electrical troubleshooting you may need some professional help.

---------------------------------------------------------------------------------------------------------

Avid Corvair hobbiest since 1984.
I have personally performed ground up restoration on over 20 Corvairs.
I currently work full time at restoring and repairing Corvairs.
Located in the Atlanta Georgia area.
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Re: Cylinder Head Temp Gauge not working
Posted by: krfjkm ()
Date: March 09, 2019 06:58PM

Ok— step by step is great what does this mean?:

1 with key “ON” is gauge”

KRFJKM
Charlotte NC
1965 Corvair Corsa
1966 Corvair Corsa (60 over with an Isky 280)

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Re: Cylinder Head Temp Gauge not working
Posted by: jjohnsonjo ()
Date: March 09, 2019 07:10PM

The phrases just below that are symptoms and possibilities of the problem.

J.O.

65 Corsa Turbo Vert
79 Honda XL 500S
69 Honda CL 160 D
2010 BMW F 650 GS
2003 Bounder 36D
2013 KIA Optima SX turbo-AKA ZIPPY (wife,s car)
69 Newport Holiday Sailboat
Baja 150 dune buggy cart
Coleman HS 500 UTV
2016 KIA Sorento SXL Turbo

Bethlehem,Pa

[corvaircenter.com]

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Re: Cylinder Head Temp Gauge not working
Posted by: joelsplace ()
Date: March 09, 2019 07:27PM

Next 3 lines are the options and answers to that question.

Oops too slow...

Joel
Northlake, TX
4 Ultravans, Lost count at 100 Corvairs...




Edited 1 time(s). Last edit at 03/09/2019 07:27PM by joelsplace.

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Re: Cylinder Head Temp Gauge not working
Posted by: vairmech ()
Date: March 09, 2019 08:14PM

OK, When you turn the key to the on position where is the gauge pointing?

Ken Hand
Handy Car Care
248 613 8586

Vairmech@aol.com

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Re: Cylinder Head Temp Gauge not working
Posted by: krfjkm ()
Date: March 09, 2019 08:30PM

I just went to the garage and cut the key on— the gauge seemed to “bury” itself to the left side. I cut the key off and back on again and it didn’t look like it was moving st all after the initial switch on.

KRFJKM
Charlotte NC
1965 Corvair Corsa
1966 Corvair Corsa (60 over with an Isky 280)

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Re: Cylinder Head Temp Gauge not working
Posted by: MattNall ()
Date: March 09, 2019 08:44PM

krfjkm Wrote:
-------------------------------------------------------
> I just went to the garage and cut the key on—
> the gauge seemed to “bury” itself to the left
> side. I cut the key off and back on again and it
> didn’t look like it was moving st all after the
> initial switch on.

=============================================

Needle moved but under 200f = gauge funtioning / open circuit to thermister / T-M bad

MODERATOR
Sea Mountain, between Charleston Harbor and Coos Bay! SW Oregon Coast
Click HERE for My Website...Click HERE for My TechPages!
..............................110-PG.................................................Webered-Turbo

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Re: Cylinder Head Temp Gauge not working
Posted by: JimBrandberg ()
Date: March 10, 2019 07:04AM

There's a single wire at the left front of the engine compartment coming out of the main harness that goes down to the sender which is under the left cylinder head. There's two other wires that go to the starter, it's not them. Sometimes this wire is disconnected.

Sometimes the wire is loose at the thermister (sender) under the head. You have to remove the lower shroud to access it. You can leave the rod connected to the damper door, loosen the 7 bolts and let the lower shroud hang to get in there. Reconnecting the rod is sort of a hassle.
The thermister wire has a small nut that takes a 1/4" wrench I think.
I had one where the thermister was loose in the head.
If the thermister is bad, it's hard to get it out when the exhaust manifold is in place.

I'm just suggesting a few mechanical things to check if you're not into electrical testing.

Jim Brandberg
Isanti, MN
CorvairRepair.com



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Re: Cylinder Head Temp Gauge not working
Posted by: vairmech ()
Date: March 10, 2019 09:58AM

OK, Now go to the rear and unplug the thermistor wire. Make a jumper wire and plug it in the body side and ground the other side.

Turn the key on what does it do?

Ken Hand
Handy Car Care
248 613 8586

Vairmech@aol.com

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Re: Cylinder Head Temp Gauge not working
Posted by: MattNall ()
Date: March 10, 2019 10:59AM

Also at this time with a voltmeter check for 10 volts!

MODERATOR
Sea Mountain, between Charleston Harbor and Coos Bay! SW Oregon Coast
Click HERE for My Website...Click HERE for My TechPages!
..............................110-PG.................................................Webered-Turbo

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Re: Cylinder Head Temp Gauge not working
Posted by: oldqmguy ()
Date: March 10, 2019 02:39PM

Here is an updated copy how to troubleshoot a Cylinder Head Temp Gauge not working. This may be a little easier to read for the new Corvair owner.

Dale cool smiley



Troubleshooting the Cylinder Head Temperature System

This is for 65-66 dashes. EM Spyder dashes will be the same except for Wire color/placements

System Check with COLD engine:

1. Turn the Ignition Key to ON and check the gauge reading:

Always over 600 f = good 12vdc to gauge/missing a ground.

Needle rises to over 600f = shorted lead to Thermistor or a bad Thermistor.

Needle moved but under 200f = gauge is functioning but not connected to the Thermistor or Thermistor is bad (OPEN).


2. Thermistor/wiring checks (Ignition Key OFF):

At the 2 wire plug behind dash measure the resistance from the Black/Light Green striped wire to Ground. It should read from 4,000 to 6,000 ohms to GROUND.

In the Engine Compartment the White High Temp lead from Thermistor should read 4,000 to 6,000 ohms to GROUND.

The Thermistor (located in the bottom of the Driver’s side Head should read 4,000 to 6,000 ohms to GROUND.

3. Gauge Checks:

With Dash Harness unplugged:

Black/Light Green wire to dash [2nd pin in from row across from open hole] to Black/Purple wire in plug [2nd pin over from empty hole] should read 50 ohms [this means that the gauge is good].

With the dash harness plugged in and the Ignition Key ON and the Thermistor disconnected you should see 10 VDC at the Thermistor connector (the one that plugs onto the Thermistor).

Dale E. Smiley CPBE
Life Member The Society of Broadcast Engineers
RETIRED Broadcast Engineer
CERTIFIED CORVAIR NUT
CORSA/Circle City Corvairs/Corvair Performance Group
Avon, Indiana
WB9SFF
1967 4-Door Monza PG!

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Re: Cylinder Head Temp Gauge not working
Posted by: MattNall ()
Date: March 10, 2019 03:10PM

Thanks Dale!

MODERATOR
Sea Mountain, between Charleston Harbor and Coos Bay! SW Oregon Coast
Click HERE for My Website...Click HERE for My TechPages!
..............................110-PG.................................................Webered-Turbo

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Re: Cylinder Head Temp Gauge not working
Posted by: Seth Emerson ()
Date: March 11, 2019 10:10AM

It is notable that the procedure for testing the Cylinder Head Temp gauge, is almost the same, except for the ranges, as testing the Fuel gauge and sender!

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Re: Cylinder Head Temp Gauge not working
Posted by: krfjkm ()
Date: March 11, 2019 06:42PM

Thanks guys!!!

Going to have some time tomorrow afternoon to crawl under the car— this info will help!

Will update with what I find.

KRFJKM
Charlotte NC
1965 Corvair Corsa
1966 Corvair Corsa (60 over with an Isky 280)

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Re: Cylinder Head Temp Gauge not working
Posted by: krfjkm ()
Date: March 12, 2019 02:36PM

Ok guys— had a chance to crawl under the car today:

- pulled the thermistor and tested it and it is good (also had a spare and tested it the same way)
- I checked for continuity from the wire at the thermistor to up to the engine compartment and it was good
-I then checked continuity from the wire in the engine compartment to the dash and it was good
- I did the test Ken Hand recommended and unplugged the wire in the engine compartment and made a jumper wire from there to a ground and turned on the key and got noting from the gauge

I am thinking that I have a bad gauge as I rechecked it and when I turn on the key it doesn’t move at all.

If you guys agree does anyone have a spare Cylinder Head Temp gauge?

KRFJKM
Charlotte NC
1965 Corvair Corsa
1966 Corvair Corsa (60 over with an Isky 280)

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Re: Cylinder Head Temp Gauge not working
Posted by: MattNall ()
Date: March 12, 2019 05:05PM

Plug it all back together but the TM itself..

Turn key ON...read voltage from wire at TM to Ground... S/B 10 volts

MODERATOR
Sea Mountain, between Charleston Harbor and Coos Bay! SW Oregon Coast
Click HERE for My Website...Click HERE for My TechPages!
..............................110-PG.................................................Webered-Turbo

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Re: Cylinder Head Temp Gauge not working
Posted by: krfjkm ()
Date: March 12, 2019 05:54PM

I did that and got nothing from the gauge or my volt meter

KRFJKM
Charlotte NC
1965 Corvair Corsa
1966 Corvair Corsa (60 over with an Isky 280)

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