Fuel gauge help!!!
Thread Starter
Intermediate
Joined: Aug 2012
Posts: 38
Likes: 0
Fuel gauge help!!!
Ok im a noob but I have a check engine light for code p0463 and my gas gauge needle goes to zero with service fuel system in status so I found thread about using techron so I did and about 160 miles later at exactly half a tank the gauge started working so I had to have the code cleared so my question is if techron treatment fixed my issue or is that sensor only hacked up at half to full cause it was weird that the gauge started working at exactly half a tank I have a appointment in morning needing advise quick so I can cancel if that fixed it I don't want to refuel check cause I want to run that tank of gas down with techron and run another through it for good measure
Team Owner
Joined: Sep 2005
Posts: 20,352
Likes: 568
From: Ventura County, Calif
Could go either way. While I hesitate to state that the Techron treatment fixes "a majority" of those gauge issues, it certainly seems to be the case.....but I have no hard evidence. If it were me, I'd cancel the appt and let it play out with at least 2 more tanks with the Techron. You can always make a new appt if it stops working again.
There have been cases where the gauge only works for that "last half tank". When you fill it up again it may not work again until it gets down to the half mark (approximately). Just knowing that much more would also assist with diagnosis toward probably needing a new sending unit.
Have you changed gas brands or stations recently? May just be a bad batch of gas that caused this.
Good luck. Let us know what happens. 
There have been cases where the gauge only works for that "last half tank". When you fill it up again it may not work again until it gets down to the half mark (approximately). Just knowing that much more would also assist with diagnosis toward probably needing a new sending unit.
Have you changed gas brands or stations recently? May just be a bad batch of gas that caused this.
Good luck. Let us know what happens.
Thread Starter
Intermediate
Joined: Aug 2012
Posts: 38
Likes: 0
I've only had the car for a week and they filled it up for me when i picked it up and about 3/4 to half a tank it went to zero and I filled it back up with the techron so I have no idea of the past on the car other then car fax I hope like hell that's it cause I don't want to foot the bill for a fuel sending unit i have a local gas station with pure has no ethanol I'm gonna go to for 93 as much as possible I'm hoping it's fixed but my luck sucks Thnks for the info I'm a complete noob with vette just traded my 03 cobra for it so I'm still learning car
Safety Car
Joined: Jul 2009
Posts: 3,755
Likes: 190
From: Baton Rouge LA
St. Jude Donor '14, '16
Sounds to me like a possibility that the drivers side sending unit COULD be at fault. Your symptoms are the same as mine were after I replaced my fuel pump and ended up with a faulty sending unit.
I would run through your gas and reschedule your appointment if needed.
I would run through your gas and reschedule your appointment if needed.
Safety Car
Joined: Jul 2009
Posts: 3,755
Likes: 190
From: Baton Rouge LA
St. Jude Donor '14, '16
About the fuel level, yes since the car has 2 tanks, there is a sending unit (fuel level sensor) in each tank. It would work until half a tank and then dive to zero.
I hope you got lucky here too. Best of luck.
Race Director
Joined: Dec 2005
Posts: 11,857
Likes: 107
From: God's Country, ID
Correct me if I'm wrong, but if you get a zero fuel reading with the tank above 1/2, and then get a good reading at 1/2 tank...then possibly your right (passengers) tank sensor would be the one with an issue. Fuel is drawn from the right tank first. Your dealer has a Tech 2 and can monitor this.
Last edited by DSOMC6; Aug 29, 2012 at 11:05 PM.
Safety Car
Joined: Jul 2009
Posts: 3,755
Likes: 190
From: Baton Rouge LA
St. Jude Donor '14, '16
Correct me if I'm wrong, but if you get a zero fuel reading with the tank above 1/2, and then get a good reading at 1/2 tank...then possibly your right (passengers) tank sensor would be the one with an issue. Fuel is drawn from the right tank first. Your dealer has a Tech 2 and can monitor this.
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Thread Starter
Intermediate
Joined: Aug 2012
Posts: 38
Likes: 0
Whenhad the code checked it was the high input so my guess is it's the half to full it won't read 
so idk I'm gonna fill it up Tommarrow and see if the techron worked or it only reads from half a tank down to empty
so idk I'm gonna fill it up Tommarrow and see if the techron worked or it only reads from half a tank down to empty
Le Mans Master
Joined: Dec 2004
Posts: 5,492
Likes: 807
From: West coast CA
Your electrical resistance of your left (driver's) fuel tank level sender is too high when the left tank is full. P0463 means that the voltage read back from that sender is high, which means that the circuit isn't sinking enough current (resistance too high). Once the fuel level drops to 1/2 tank, the left tank sender starts moving and the resistance drops into the normal range.
The most likely cause is that your fuel level sender is dirty. Also, for '05s there was a firmware update that addressed this issue.
Techron kinda sorta helps for a while but you may need to step up and have the senders replaced. I'd replace both at the same time.
The most likely cause is that your fuel level sender is dirty. Also, for '05s there was a firmware update that addressed this issue.
Techron kinda sorta helps for a while but you may need to step up and have the senders replaced. I'd replace both at the same time.
Melting Slicks
Joined: Dec 2006
Posts: 2,694
Likes: 106
Another possibility is the venturi-type fuel tube where the right tank is drained first could be clogged, and since the left fuel tank goes down in level before right one is empty, system throws a code. At any rate, I'd run 2 tanks with Techron and see if the problem goes away. If not, I'd start with the right tank, but the venturi is on the left one. I'd use Chevron fuel from now on if I were you. Or at least often. Good luck.
Melting Slicks
Joined: Dec 2009
Posts: 2,504
Likes: 66
From: Louisville, KY
I had a similar issue with my C5. It took 3 tank fill ups with a can of techron at each fill up to fix it. Never had another problem with it after that. I continued to use techron in the C5 about every 4-5th fill up afterwards.
Team Owner
Joined: Sep 2000
Posts: 25,001
Likes: 2,700
From: Far NW 'burbs of Chicago
St. Jude Donor '13
A cheaper and more convenient way to accomplish the same thing, after a couple of tankfuls with Techron, is to always buy gas from one of the Top Tier brands (Google) and then add the Techron occasionally. I only use it once per year (15k-20k miles) because the car has had Top Tier gas since new and never any gauge problems. You might want to do it somewhat more frequently.
And hey, Welcome Aboard and enjoy your car!!!
And hey, Welcome Aboard and enjoy your car!!!
Team Owner
Joined: Sep 1999
Posts: 41,732
Likes: 1,718
From: Springfield MO
A cheaper and more convenient way to accomplish the same thing, after a couple of tankfuls with Techron, is to always buy gas from one of the Top Tier brands (Google) and then add the Techron occasionally. I only use it once per year (15k-20k miles) because the car has had Top Tier gas since new and never any gauge problems. You might want to do it somewhat more frequently.
And hey, Welcome Aboard and enjoy your car!!!
And hey, Welcome Aboard and enjoy your car!!!
Top tier plus Techron