Fuel Sending Unit Error

[Lyle B.]

I am wondering if anyone would know how to correct an error with the sending unit or fuel gage. When I fill up my gas tank the fuel gage reads almost full. When I drive it for a while it goes to "E"-empty. When I go to fill it up it only takes 7.2 gallons on a 18 gallon tank. This has a NOS fuel gage and a new sending unit. Are these gages all off for this year? Your help and advice would be greatly appreciated.

[Patrick H.]

Re: Fuel Sending Unit Error

You don't mention what year it is, but I assume you're referring to your 1975 convertible as per your profile.

What this reminds me of is the infamous "collapsing bladder syndrome." On original tanks, the fuel tank had a "safety bladder" installed. This bladder often "collapses" as it ages, resulting in the EXACT symptoms you describe - inaccurate gauge readings and small tank volumes.

As with medicine, you need to have a TURP done (or maybe closer to a cystectomy....), and Flomax or Ditropan won't do much for you here.
Well, in your case, you can actually cut out the bladder and leave the metal fuel tank like all the rest of us with older Corvettes had. See the Archives for descriptions on how to do this. Once your "collapsing bladder" has been removed you will be back to a correctly functioning tank, gauge and sending system. Plenty of other old Corvettes have undergone this procedure with good results.

Good luck.

Patrick

[Dennis A.]

Re: Fuel Sending Unit Error

Lyle...

Best check out the ground wiring. Could be coming lose during driving. If the car is a C1, I advise running another ground wire from the sender to the frame.