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Old 08-12-2017, 12:32 PM   #1
Okie528
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Installed '90 GM Factory EFI tank, '72 Blazer Factory fuel gauge is pegged past full?

Installed '90 GM Factory EFI tank, '72 Blazer Factory gas gauge is pegged past full? I know the ohms are the same, just curious if anyone else has run into this problem, and how I can fix it. I did the swap so I could use an in-tank pump for my Holley Sniper EFI. Thanks in advance.
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Old 08-13-2017, 06:48 PM   #2
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Re: Installed '90 GM Factory EFI tank, '72 Blazer Factory fuel gauge is pegged past f

Ok, ground is good. My sending unit is a four wire (Gray wire - Fuel pump power, Purple - Sending unit, Black w/white stripe-I assume ground, then another black wire-ground. I have the both the black and black with white stripe grounded to the same spot. Does this shed any light to my problem? Truck runs as it should, just no fuel gauge.
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Old 08-13-2017, 07:55 PM   #3
'68OrangeSunshine
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Re: Installed '90 GM Factory EFI tank, '72 Blazer Factory fuel gauge is pegged past f

When the Lt Brown wire from the float sending unit is open or unplugged, the pointer goes to 3 O'Clock. Check that line and connection.
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Old 08-14-2017, 11:36 AM   #4
A1971Blazer
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Re: Installed '90 GM Factory EFI tank, '72 Blazer Factory fuel gauge is pegged past f

Andy...here is a good write up......http://67-72chevytrucks.com/vboard/s...d.php?t=640615
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Old 08-14-2017, 12:27 PM   #5
'68OrangeSunshine
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Re: Installed '90 GM Factory EFI tank, '72 Blazer Factory fuel gauge is pegged past f

On my '71 Jimmy, the PO let the tan wire contact the exhaust pipe and it burned out long ago. Since it's a major production to first drop the trailer hitch, then the 1/4'' steel armor plate around the fuel tank, til I can get to the tank straps and then, drop it -- I haven't done it yet. Replacing the Tan [or Lt Brn] wire is the easy part.
As a work-around, I have a clipboard in the cab where I log my miles, gas gallons bought, date, octane, price and many other details. That way I can 'cypher' my MPG vs. fuel onboard, and calculate what my gas level is [or should be]. Not the most practical solution, I'll admit. Fixing the wire or in-tank sender, would be better. Having a working accurate fuel gauge makes it a no-brainer. But I can carry a pretty accurate picture in my head of fuel usage, with the clipboard, and I'm used to it. When in doubt just add 10 gallons every 100 miles.
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Old 08-14-2017, 03:25 PM   #6
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Re: Installed '90 GM Factory EFI tank, '72 Blazer Factory fuel gauge is pegged past f

Sorry off topic but what did you use to reduce down to the 1 3/8 filler neck?

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Old 08-14-2017, 10:53 PM   #7
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Re: Installed '90 GM Factory EFI tank, '72 Blazer Factory fuel gauge is pegged past f

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Sorry off topic but did you use to reduce down to the 1 3/8 filler neck?
The guys at fillernecksupply.com helped me out. I think its a 1 3/8 to 1 3/4 reducer to a 1/4 rubber sleeve (can't remember the name for it) into a 2" filler hose. I just called them and they figured out how to get me there.
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Old 08-14-2017, 10:58 PM   #8
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Re: Installed '90 GM Factory EFI tank, '72 Blazer Factory fuel gauge is pegged past f

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Originally Posted by A1971Blazer View Post
Andy...here is a good write up......http://67-72chevytrucks.com/vboard/s...d.php?t=640615
Great info! Thanks for the link.
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