jjaaam

I've read about the dreaded gas-gauge-drop-to-zero issue ever since I came to this forum and started looking up info on my C5. As noted in a post I made in a recent thread, it happened to me a week ago; roughly 1/2 tank, dropped to zero, P1431 code, reset code, filled tank, problem went away...for now.

I've also seen the nauseatingly (is that even a word?) amount of $$$ that it can cost to possibly fix the problem by putting in new sending units.

My question is this: if it ever gets to the point that I'm having the issue on a frequent basis, couldn't I just set the trip meter when I fill up and assume approximately 400 miles to a tank?

I ask because I wonder about the tank pump setups...is it possible to drain one tank, have the other one be full of fuel, and STILL run out of gas?

PITA maybe...and pretty much unacceptable on GM's flagship Chevy...but it is what it is. I will put Techron in but I refuse to pay over $1000 to fix what may be just an annoyance.

Thoughts?

Choreo

Yes, if the jet pump in the passenger tank gets clogged.

jjaaam

OK. If that happens then it would make sense that the issue would happen around the 1/2 full mark. I guess I would just fill up when I get closer to that point.

IT just seems like an unGodly amount of cash to fix this - and even then there are those that HAVE had the senders replaced and still have the issue...

K9Leader

My '99 has it on and off. I have to have been driving for about an hour, with the tank starting out at 3/4 to full. After about an hour, when the needle is between 5/8 and 3/4, it will go to E. If I keep driving, it will flip back to normal in about another hour at about just below the 1/2 tank level. Of course, stopping and turning the engine off and then restarting sets it all back to normal (known as the "Windows" fix).

I use quality gas, usually Shell, sometimes Exxon (no Chevron in my area) and put Techron in every few tankfuls. Sometimes I think the problem is gone - went on a 2800 mile, 7 day road trip two years ago without a single incident - but then it pops up again. It is an annoyance and I am not willing to shell out the big bucks for a fix that may not permanently solve the problem.

K9Leader

torchredmadness

Ours goes to empty every time we get gas which is usually every time we get to 1/4 of a tank. After maybe 5 miles it goes back to normal. We don't find that to be a problem at all.

JR-01

I had the problem all summer even after using Techron every fill. Then I tried putting one bottle in before filling and one bottle in after full. I then drove 2 miles home and let it sit for a week. The problem was gone. I thought maybe when I filled it after putting Techron in, not enough was getting into the right tank. Not sure if was just a coincidence or not.
I just put it in storage for the winter and put 2 bottles of techron in to clean the contacts for 6 months. Hope it is OK in the spring.

kabluie

If you are going to use the trip meter method, I would suggest 300 miles for in town driving.

Corvette_Ed

I see my '00 coupe as a trade-off of sorts.

I can access my fuel sending units without dropping the tanks, and can do so in my own driveway, saving myself thousands of $$$.

On the other hand, the EBCM is an issue, and can end up costing me a grand or more if mine ever fails.

When it comes down to it, seeing as my sending units are messed up and need to be replaced, I think I'm actually ahead money-wise considering what a stealership would charge to drop the tanks and replace sending units on newer models.

JR-01

Many of these common problems should have been recalled by GM. Especially the EBCM. GM knew they had a defect, but figured they could make a fortune replacing them after warranty was up.

Vetteman Jack

If you haven't tried the Techron as mentioned above, give it a shot for a few tanks of gas. Could just be sulfur deposits on the sending units that need to be cleaned.

Lazarus Long

Is the Techron something that should be done on a regular basis, or just if you have a problem? Far as I know, it has never been used in my 98, I have not seen this problem. It only has 16000 miles.

JR-01

It wouldn't hurt to use it in the 2 tankfuls of gas you burn through in a year.

donald4972

Lot's of good evidence that techron helps with this C5 issue. Guys for many years, with lots of C5 knowledge swear by it.
I use it, every few tankfuls (3-5), in all my cars.

The bottom line is this, seems to me. Like taking a vitamin C tablet. Can't possibly hurt anything. And most probably is helpful, even if you are skeptical.

I'm a believer, and buy techron by the case when it's on sale from time to time (Costco, the auto parts stores, etc).

Don

jackthelad

Here ya go, it's a software upgrade (thanks to Joeflyer for TSB info):

http://www.corvetteforum.com/forums/...post1586371657

I had the reflash done on my 98 some years back - Techron had made no difference. Hasn't happened once since - and it used to happen all the time.

Lazarus Long

Another stupid question: are the sending units unique to the corvette,or is it a generic part used in lots of GM vehicles? I also have a 97 Tahoe, it has never had any fuel gage issues.

The right pump failure would be annoying, but I've read that it doesn't have any or very few moving parts, so that should be rare.

Tony1M

I'll add to the stupid question list.

I've never owned a car or motorcycle whose fuel sending unit experienced the same problems as those I've read about in this forum with respect to those in the C5. Does the rubbing/moving part of the fuel sending units (in addition to the floats) in the C5 actually sit right in the fuel? Do the sending units in other vehicles also sit in the fuel? If they do, why don't they experience the same problems as the C5s? If they don't, why didn't GM keep their sending units out of the fuel, too?

JR-01

Silver contacts prone to sulfer build up for '01 and previous years seemed to be the problem if I am not mistaken..It was corrected when they changed to a different metal.

Tony1M

Doesn't this sender problem go right through the C5 generation into the C6?

JR-01

I don't know. Maybe someone else could enlighten us. I think there are several defects in the fuel tank system and Techron only will correct the sulfur build up one.

K9Leader

The sulfur buildup is often the problem but is not the only reason the sending unit is intermittent. As it was explained to me by a Corvette specialist mechanic, the contacts are finger-like prongs held against the contact by tension. The sulfur buildup can cause the loss of contact but over time the tension lessens and contact can be lost at various points as the sender travels down with the fuel level. A combination both of these could explain why my car tends to experience the problem at certain levels (usually between 1/2 and 3/4 full).

I could be totally wrong about this as I am about many things - just ask my 23yo daughter.

K9Leader