Fuel Sending Unit

[Ken A.]

Re: Fuel Sending Unit

ALL Corvette GM senders from 56 t0 97 are now produced in China, period. But, not all Chinese senders are made to GM specs. There are least 20 fuel sender cos in China making everything from OEM to that "junk" some of you refer to. If you want GM "spec'ed, e-85 compliant " senders look no further than Zip or Paragon. The correct GM, AC-Delco, Delphi senders will have the plastic"film" resistor, not the old style resistor that is affected by the high sulphur content of today's gas. If you payed under $60 for any sender, then you got hosed, And, NOBODY is converting the old style senders to the modern resistors-you clean an old one and it will fail again.
Let the experts speak, now.

[Jim D.]

Re: Fuel Sending Unit

ALL Corvette GM senders from 56 t0 97 are now produced in China, period. But, not all Chinese senders are made to GM specs. There are least 20 fuel sender cos in China making everything from OEM to that "junk" some of you refer to. If you want GM "spec'ed, e-85 compliant " senders look no further than Zip or Paragon. The correct GM, AC-Delco, Delphi senders will have the plastic"film" resistor, not the old style resistor that is affected by the high sulphur content of today's gas. If you payed under $60 for any sender, then you got hosed, And, NOBODY is converting the old style senders to the modern resistors-you clean an old one and it will fail again.
Let the experts speak, now.

So what you're saying is that the one for $70 from Zip is good but because I bought the identical one (in a side by side comparison including the box) elsewhere for $50, mine is junk.

[Ken A.]

Re: Fuel Sending Unit

So what you're saying is that the one for $70 from Zip is good but because I bought the identical one (in a side by side comparison including the box) elsewhere for $50, mine is junk.

Sounds like you got a steal-I'm referring to the $30 ones on flea bay.

[Ronald L.]

Re: Fuel Sending Unit

Ken,
The $80 Paragon part and the nearly same part from CC, one measured 150 ohms full and the other 200 ohms.

A part with that level of WRONG resistance will never get better on its own and will never register full either.

The Delphi part I got cost more that 3x and a blind man can see the difference in these parts. I'll post a photo when I get home later in the week, I have these things queued up side by side.

There was also an interesting story about how the engineers were taking the early parts to some place in Warren because the calibration was off, in other words, full was not = 90 ohms and empty not = to 0 ohms.

The stainless modules can be spotted a mile away as just that.

There was also an availability issue that came up later which may be due to a manufacturing site change.

[Jack H.]

Re: Fuel Sending Unit

"A few years ago, there was a rumor going around that the import sending would burn your Corvette to the ground. Some idiot may have burned his Corvette to the ground but it wasn't because of the sending unit."

Methinks you should check facts before declaring the 'truth' as you believe it to be. The 'idiot' was ME. I'm an electrical engineer and there WAS a design/production fault with the early Chinese sending units many years ago.

The Corvette mid-year fuel gauge system is unique based on a Whetstone bridge electrical circuit topology. One of the service techs at our shop installed a recently received reproduction sender unit and brought it to me as it was 'defective'.

I gave him another from stock and being curious tore into the 'bad' one he'd used. The nichrome wire windings in the sender's potentiometer had MELTED and open circuited. Interesting...

Before I could look further, the tech came back saying the second unit was also 'bad'. I put him onto another job until I could figure out what was up here. Sure enough the second sender had melted its pot windings too.

I grabbed the third/last reproduction sender we had in stock and analyzed it. It was intact, BUT the way it was constructed was WRONG!

It wasn't wired to form a Whetstone bridge and when the float hit its low/empty position, it essentially formed an electrical short circuit! That's why the pot windings were burning out/melting down...

I dropped everything and called the catalog vendor who'd supplied us with these newly made reproduction parts. I assured the catalog house's tech staff that we had a threat to life, limb, property situation here that required EMERGENCY action.

If that car's gas tank had been freshly drained & opened, there could have been residual gas vapors present when the replacement sender was installed. If it'd been electrified without refilling the tank, there was a reasonable chance for those vapors to have ignited when the sender's pot windings over-heated and melted down!!!!

I wasn't taken seriously by the catalog tech staff, but they reluctantly bumped me up the line to the President/CEO. I re-told my story. He told me to sit tight while he investigated and confirmed my information...

He called me back within an hour and THANKED me for the information. He said he'd only shipped a few of these new reproduction senders, that he'd do a product recall and get them back and then CORRECT the off-shore manufacturing problem IMMEDIATELY.

In the meantime, he replaced the three senders we'd purchased with three real McCoy GM/AC senders. He did.

Bottom line, names/dates have been intentionally withheld. But, I guess I don't like being called an 'idiot' by someone who wasn't there and wasn't privy to the facts of the case...

[Ronald L.]

Re: Fuel Sending Unit

Jack, Welcome back!

I sure hope you did not mean me, I believed that story when I heard it and my own experiences and loss of shipping costs, gas money etc validate that China makes junk! I would not touch one with a 100 foot pole.

[Ken A.]

Re: Fuel Sending Unit

[quote=Jack Humphrey (17100);516939]"A few years ago, there was a rumor going around that the import sending would burn your Corvette to the ground. Some idiot may have burned his Corvette to the ground but it wasn't because of the sending unit."

Methinks you should check facts before declaring the 'truth' as you believe it to be. The 'idiot' was ME. I'm an electrical engineer and there WAS a design/production fault with the early Chinese sending units many years ago.

The Corvette mid-year fuel gauge system is unique based on a Whetstone bridge electrical circuit topology. One of the service techs at our shop installed a recently received reproduction sender unit and brought it to me as it was 'defective'.

I gave him another from stock and being curious tore into the 'bad' one he'd used. The nichrome wire windings in the sender's potentiometer had MELTED and open circuited. Interesting...

Before I could look further, the tech came back saying the second unit was also 'bad'. I put him onto another job until I could figure out what was up here. Sure enough the second sender had melted its pot windings too.

I grabbed the third/last reproduction sender we had in stock and analyzed it. It was intact, BUT the way it was constructed was WRONG!

It wasn't wired to form a Whetstone bridge and when the float hit its low/empty position, it essentially formed an electrical short circuit! That's why the pot windings were burning out/melting down...

I dropped everything and called the catalog vendor who'd supplied us with these newly made reproduction parts. I assured the catalog house's tech staff that we had a threat to life, limb, property situation here that required EMERGENCY action.

If that car's gas tank had been freshly drained & opened, there could have been residual gas vapors present when the replacement sender was installed. If it'd been electrified without refilling the tank, there was a reasonable chance for those vapors to have ignited when the sender's pot windings over-heated and melted down!!!!

I wasn't taken seriously by the catalog tech staff, but they reluctantly bumped me up the line to the President/CEO. I re-told my story. He told me to sit tight while he investigated and confirmed my information...

He called me back within an hour and THANKED me for the information. He said he'd only shipped a few of these new reproduction senders, that he'd do a product recall and get them back and then CORRECT the off-shore manufacturing problem IMMEDIATELY.

In the meantime, he replaced the three senders we'd purchased with three real McCoy GM/AC senders. He did.

Bottom line, names/dates have been intentionally withheld. But, I guess I don't like being called an 'idiot' by someone who wasn't there and wasn't privy to the facts of the case...

Jack,
Are you refering to the Fargo units & RC? The current GM supplier's parts were tested for 10,000 cycles, well beyond an original unit. As you know, GM is rather sensitive to fuel tank fires.
Ken

[Jack H.]

Re: Fuel Sending Unit

As stated, this was MANY years ago when the non-GM reproduction tank senders first appeared and names/dates have been intentionally withheld.