C4 gas gauge problem - Help!
#1
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Thread Starter
C4 gas gauge problem - Help!
I have a 1990 coupe and the digital gas gauge generally shows the tank full od fuel even when the tank is close to empty. A chevy dealer once told me that the fuel pump and sending unit is inside the gas tank and to fix this would be about $800.
Is there a way to verify what the issue is with the gas gauge not registering correctly?
Is there a way to verify what the issue is with the gas gauge not registering correctly?
Last edited by lovmy90vette; 10-26-2015 at 05:30 PM.
#2
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Most likely the assembly will have to come out so you can see whats up, could be a stuck float assy. or the tank inner cell wall interfering with the float.
#3
Le Mans Master
Whole assembly....remove your fuel pump and transfer over....
http://www.rockauto.com/catalog/x,ca...,parttype,4436
Easy fix....if you have never changed out the fuel pump....allow yourself 1 hour.....
http://www.rockauto.com/catalog/x,ca...,parttype,4436
Easy fix....if you have never changed out the fuel pump....allow yourself 1 hour.....
#4
easy fix dealer is ripping you
#5
Team Owner
I have a 1990 coupe and the digital gas gauge generally shows the tank full od fuel even when the tank is close to empty. A chevy dealer once told me that the fuel pump and sending unit is inside the gas tank and to fix this would be about $800.
Is there a way to verify what the issue is with the gas gauge not registering correctly?
Is there a way to verify what the issue is with the gas gauge not registering correctly?
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FASTAZU (10-26-2015)
#6
Race Director
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whalepirot (10-29-2015)
#7
Melting Slicks
An alternative source of information:https://www.corvetteforum.com/forums...h-article.html
This is the in-tank variable resistor- the winding and fragile contact:
Top center is one of two wires from the sender. I cleaned both where they plug into the assembly's mount, using DeOxIt contact cleaner, sliding the pin on and off to scrub.
The half-arc inside the D-shaped case is the rather delicate winding, a variable resistance created via more wire between the contact's position on it and ground. The delicate spring contact is to the right. Look closely at this, and the sharp eyed will see a dab of solder. Cleaning it was fine, but the problem remained. I found it by checking all resistances between components.
The culprit was the brass contact's poor connection to the springy U-shaped portion attached to the sender's arm. The dash 'sees' total resistance in the circuit and any extra along the way will drive the gauge towards full.
Using my solder iron, a nice dab of flux paste o clean the brass on both sides, I applied that small dab of solder.
Now the circuit resistance varies for the first time in many years, from near 0 ohms, to around 125. I tested it before reinserting the assembly into the tank as verification and was surprised to see how slowly the bar graph displayed moved, when the float arm did.
I also chose to bend the float arm slightly so the float bottoms out 14" below the mounting flange, as the tank measureds. It was full-down at 14.5" so the tank would show fuel remaining, when there was none.
Only a drive or three can verify if that was a mistake.
Now, I get to relearn what F and E means in real life!
Last edited by whalepirot; 11-02-2015 at 11:05 PM.
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Nilak (04-02-2024)
#8
Team Owner
"F" means you drive for a while. "E" means that if you drive too long, your Chevy becomes a Ford.
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Nilak (04-02-2024)
#9
Melting Slicks
#10
Melting Slicks
I have a 1990 coupe and the digital gas gauge generally shows the tank full od fuel even when the tank is close to empty. A chevy dealer once told me that the fuel pump and sending unit is inside the gas tank and to fix this would be about $800.
Is there a way to verify what the issue is with the gas gauge not registering correctly?
Is there a way to verify what the issue is with the gas gauge not registering correctly?
Is an easy job to remove the fuel sender unit, in my case I found the tank had started to collapse.. The wall of the tank was sucked inward stopping the float from going down, kept showing full.
I bent the sender float to clear it, popped the tank out but it had done it again. Will replace the tank and check the charcoal canister and valve at the same time. Something is obviously wrong. You really need to remove the sender and have a look and feel. Then try remove the gas smell from your arm lol
The little woman hates gas smells ...
#11
Advanced
Thread Starter
The gas Gauge problem......
Hey, thanks so much all of you for the info to fix my gas gauge. The video was great especially cuz I am not the best mechanic. So if I replace the "whole Assembly" is that the same as the Fuel Tank Sending Unit that costs $211.79?
#12
make sure it comes with the pump
#13
Team Owner
#14
Advanced
Thread Starter
Whole assembly....remove your fuel pump and transfer over....
http://www.rockauto.com/catalog/x,ca...,parttype,4436
Easy fix....if you have never changed out the fuel pump....allow yourself 1 hour.....
http://www.rockauto.com/catalog/x,ca...,parttype,4436
Easy fix....if you have never changed out the fuel pump....allow yourself 1 hour.....
So if I just buy this new Fuel Tank Sending Unit for $211, that's all I need to do? - John White
#15
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#16
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I just bought one for my 85 about a month ago from rock auto. It is the entire unit, don't need anything else. Real easy fix! Just do it!
#17
Team Owner
Also, if the screws aren't stainless, I'd get SS bolts. The PO decided to use some regular crap and I had a hell of a time getting it out.
Last edited by aklim; 11-12-2015 at 06:33 PM.
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Dirttracker (11-28-2017)