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Temperature gauge incorrect by ironpuke84
Started on: 12-29-2021 05:43 PM
Replies: 6 (145 views)
Last post by: Mike in Sydney on 01-07-2022 03:19 AM
ironpuke84
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Report this Post12-29-2021 05:43 PM Click Here to See the Profile for ironpuke84Send a Private Message to ironpuke84Edit/Delete MessageReply w/QuoteDirect Link to This Post
So I have an 84 Fiero SE, and the temperature gauge motor works, it always moves when I go to start it, but it's always reading as if the engine is overheating (even though it's not.) Any ideas what the problem is? Thanks.

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Gall757
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Report this Post12-29-2021 06:34 PM Click Here to See the Profile for Gall757Send a Private Message to Gall757Edit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by ironpuke84:

it always moves when I go to start it


Does it move violently to the right? Do a search for Temp Gauge Fix.

https://gafiero.org/temp_gauge_repair.shtml

[This message has been edited by Gall757 (edited 12-29-2021).]

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theogre
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Report this Post12-29-2021 07:48 PM Click Here to See the Profile for theogreClick Here to visit theogre's HomePageSend a Private Message to theogreEdit/Delete MessageReply w/QuoteDirect Link to This Post
Ignore trying any version of "gauge fix" like above until find why doesn't work to read engine temp.

read Ω on sender w/ engine cold and warm/hot.
Sender output pin and block should see Ω change as engine gets warm. Don't bother exact Ω.

Wire off sender gauge should peg and stay until sender get connected again.

try those first.

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ironpuke84
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Report this Post12-31-2021 05:50 PM Click Here to See the Profile for ironpuke84Send a Private Message to ironpuke84Edit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by Gall757:


Does it move violently to the right? Do a search for Temp Gauge Fix.

https://gafiero.org/temp_gauge_repair.shtml



Yes, when starting it. Once the engine is running, it goes back to 100. However, once warm, it still reads 100 degrees. Here's an image of the gauge when the engine is turning over, for further clarification.
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ironpuke84
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Report this Post12-31-2021 05:51 PM Click Here to See the Profile for ironpuke84Send a Private Message to ironpuke84Edit/Delete MessageReply w/QuoteDirect Link to This Post

ironpuke84

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Member since Dec 2021
 
quote
Originally posted by theogre:

Ignore trying any version of "gauge fix" like above until find why doesn't work to read engine temp.

read Ω on sender w/ engine cold and warm/hot.
Sender output pin and block should see Ω change as engine gets warm. Don't bother exact Ω.

Wire off sender gauge should peg and stay until sender get connected again.

try those first.



ok, will do.
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Brivander
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Report this Post01-06-2022 11:56 AM Click Here to See the Profile for BrivanderClick Here to Email BrivanderSend a Private Message to BrivanderEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by ironpuke84:


Yes, when starting it. Once the engine is running, it goes back to 100. However, once warm, it still reads 100 degrees. Here's an image of the gauge when the engine is turning over, for further clarification.


My 1984 pegs as well while cranking, that is normal. My gauge also reads low, when at full operating temp I see about 160-degrees (second tick), so not as low as yours. I just know anything above that is an issue. I've checked the temp at the thermostat and it's around 190 give or take a few degrees when fully warmed up.

I also pulled the thermostat to make sure it wasn't hung open, and boiled it to make sure it opened properly @ 195. All was well.

[This message has been edited by Brivander (edited 01-06-2022).]

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Mike in Sydney
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Report this Post01-07-2022 03:19 AM Click Here to See the Profile for Mike in SydneySend a Private Message to Mike in SydneyEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by ironpuke84:

So I have an 84 Fiero SE, and the temperature gauge motor works, it always moves when I go to start it, but it's always reading as if the engine is overheating (even though it's not.) Any ideas what the problem is? Thanks.


If it moves violently to the right when turning the key on then the likelihood is that the known wiring issues has never been corrected. See https://gafiero.org/temp_gauge_repair.shtml for the fix.

If it's reading high after warming up but not over heating, the chances are that the continual pegging of the gauge due to the wiring issue has cause the needle to slip on the shaft resulting in an abnormal reading. Try warming the engine and checking the coolant temperature with a infrared thermometer to get a sense of how far off it may be.

BTW, somewhere on the web, I've seen instructions on how to pull off the needle on the temp gauge and re-fix it in the proper position. Just can't find it now. Look here for other's that have had similar problems. https://www.fiero.nl/forum/...110502-2-102240.html
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