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Old 08-12-2017, 10:51 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 and not working? 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 to use with my Holley Sniper EFI, but really want to keep the factory gauges. Thanks in advance.
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Old 08-12-2017, 11:21 PM   #2
dec010974
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Re: Installed '90 GM Factory EFI tank, '72 Blazer Factory fuel gauge is pegged past f

hello Okie528. I have had this happen to me before. Check the wiring. make sure you have the correct fuel wire hooked up. In my case, I had the fuel sending unit wiring hooked up wrong. I hope you have an easy fix. Good luck, Clark.
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Old 08-12-2017, 11:55 PM   #3
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Re: Installed '90 GM Factory EFI tank, '72 Blazer Factory fuel gauge is pegged past f

might want to pull the float/sender out of tank and make sure the floats not stuck...
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Old 08-13-2017, 06:47 PM   #4
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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 hooked to my tan sending unit wire, 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?
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Old 10-19-2019, 11:30 PM   #5
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Re: Installed '90 GM Factory EFI tank, '72 Blazer Factory fuel gauge is pegged past f

Hey Okie, I know this thread is old but, just curious where you purchased your Blazer fuel tank from? Is the fuel fill on the driver's side?
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Old 10-20-2019, 06:58 PM   #6
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Re: Installed '90 GM Factory EFI tank, '72 Blazer Factory fuel gauge is pegged past f

did you ground the sender ground wire to the FRAME ?

this will get you a bad over full pegged needle .

also did you swap in a bigger psi / flow pump to feed the higher psi required sniper ?

i did a ep381 acdelco unit direct plug and play swap . worked for my super short run with the sniper and been great with the edelbrock pro flo 4 now no problems .
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HOLLEY SNIPER efi = worst case of p.i.t.a i ever had .

EDELBROCK pro flo 4 = best deal going so far . love my setup works great.
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Old 10-21-2019, 08:44 AM   #7
A1971Blazer
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Re: Installed '90 GM Factory EFI tank, '72 Blazer Factory fuel gauge is pegged past f

Quote:
Originally Posted by Cledus Snow View Post
Hey Okie, I know this thread is old but, just curious where you purchased your Blazer fuel tank from? Is the fuel fill on the driver's side?
I bought this 72 Blazer from my buddy Andy (Okie 528) last May

Looking through his receipts...the fuel tank is a Spectra GM-14G specs out for a 1991 C3500

I know that he went through ordering and returning a couple of different tanks before he found that one....the first tanks did not have a baffle surrounding the pump.

The fill is in the stock location

It did require some modifications to the rear cross members...not sure of the exact details but I can look if you'd like
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Old 10-22-2019, 12:56 AM   #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
I bought this 72 Blazer from my buddy Andy (Okie 528) last May

Looking through his receipts...the fuel tank is a Spectra GM-14G specs out for a 1991 C3500

I know that he went through ordering and returning a couple of different tanks before he found that one....the first tanks did not have a baffle surrounding the pump.

The fill is in the stock location

It did require some modifications to the rear cross members...not sure of the exact details but I can look if you'd like
Thank you for the info and the part number, I really appreciate. If you could take a picture of the modifications that would be awesome. Thanks.
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Old 10-22-2019, 09:26 AM   #9
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Re: Installed '90 GM Factory EFI tank, '72 Blazer Factory fuel gauge is pegged past f

Have you checked the (ohms) of the sender, 90 ohms ? move the lever of the sender up and down and see the difference in the Ohm readings. Also, are you using the factory gas gauge for a 72 Blazer, they have a resistor on the back side of the gauge which could be bad... I believe the factory gauge resistor is a 90 ohms resistor. Good Luck !
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Old 10-22-2019, 09:49 AM   #10
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Here is a pic of the gas gauge resistor on back side of cluster.
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Old 10-22-2019, 09:52 AM   #11
A1971Blazer
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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 YoungPup1977 View Post
Have you checked the (ohms) of the sender, 90 ohms ? move the lever of the sender up and down and see the difference in the Ohm readings. Also, are you using the factory gas gauge for a 72 Blazer, they have a resistor on the back side of the gauge which could be bad... I believe the factory gauge resistor is a 90 ohms resistor. Good Luck !
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Here is a pic of the gas gauge resistor on back side of cluster.
Posted via Mobile Device
Thanks for the input....
this thread is old and the gauge issue was solved
I bought the Blazer from the OP last May and all is well with it
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Old 10-22-2019, 10:16 AM   #12
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Re: Installed '90 GM Factory EFI tank, '72 Blazer Factory fuel gauge is pegged past f

LOL!!!! Another forum issue with no solution....implement a root cause analysis to make this forum useful. Open a thread but only be able to close a thread by a solution but again that makes to much sense, I am trying to understand how this world is today...like any thing, garbage in garbage out LOL!!!!!
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Old 10-22-2019, 10:53 AM   #13
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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 YoungPup1977 View Post
LOL!!!! Another forum issue with no solution....implement a root cause analysis to make this forum useful. Open a thread but only be able to close a thread by a solution but again that makes to much sense, I am trying to understand how this world is today...like any thing, garbage in garbage out LOL!!!!!
Read the thread...the OP doesn't own this Blazer anymore
FYI....the gauge itself was faulty....problem solved......end of thread
Happy?
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Old 10-22-2019, 11:27 AM   #14
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Re: Installed '90 GM Factory EFI tank, '72 Blazer Factory fuel gauge is pegged past f

Wow !!! Thanks !!!! Even WOODCHUCKs TRUCKs was tiring to help..... LOL!!!!

Last edited by YoungPup1977; 10-22-2019 at 11:42 AM.
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Old 10-22-2019, 12:35 PM   #15
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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 YoungPup1977 View Post
Wow !!! Thanks !!!! Even WOODCHUCKs TRUCKs was tiring to help..... LOL!!!!
you're welcome...if you have problems with your fuel gauge...let me know..I'll be glad to load you up with possible solutions and a plethora of smartass answers....
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