luke87gt

Hi guys, as I posted last week, I just picked up a 2003 Z06.

Everything seems to work great on it except one thing. When the gas gauge reaches about 3/4 full (so only 1/4 tank burned), the gauge drops to 0 and I get a "check gage" light on the dash. Sometimes it comes back, other times it doesn't. Refilling brings the gauge back up to full.

I did a search and came up with an absurd amount of posts with C5 corvette owners complaining about the same problem. I've noticed some differentiation between what level of gas the gauge drops to 0 and displays error.

Reading through the various threads, it sounds like gas brand can potentially play a role as some brand have more sulfur content than others which causes these sending units to malfunction. Here are some recommended things to try:

a.) Always use Chevron gas and perform a few treatments of Techron Plus, Seafoam, or GM fuel injector cleaner. I tried my first bottle of Techron at the last fillup, but it didn't help. I'll do two more treatments just to be sure

b.) Reflash the computer at the dealer. Although this doesn't fix the problem, the reflash uses error settings that are less sensitive (wider fuel sending unit voltage window) compared to the original settings. I've heard mixed opinions about this.

c.) Clean the fuel sending units connections with electric parts cleaner (requires dropping the tank). This requires a lot of labor for something that might not help.

d.) Replace the sending units in both tanks. I've heard that GM quotes about $1700 parts + labor and this usually fixes the issue for some period of time but the problem sometimes resurfaces once those sending units accumulate sulfur again. The price seems outrageous.

A few questions:

1.) Does anyone know of any recalls/TSBs related to this problem that you can share (TSB number would be very helpful)

2.) Is there any GM parts warehouse where I can get the two sending units cheaper than the dealers?

3.) I notice that Rockauto.com and Oreillysauto.com are showing these units for cheap (about $50-60 each) from ACDelco, with warranty. I'm wondering if anyone has tried them? These seems to be significantly cheaper than the dealer (which we know suck). So disappointed in GM for these fuel sending units.

http://www.oreillyauto.com/site/c/se...make=Chevrolet

I'll give the Techron a chance with couple more treatments, but I don't anticipate this helping in the long run and I'm guessing that I will have to replace those sending units at some point.

Thanks,

Luke

Adrians99FRC

I think the fuel gauge in mine is acting up a little, but nowhere near as bad as yours

Try the techron .. A lot of people say it works

If not gm parts, contact a few vendors on here such as gene .. Look in the vendor for sale section for the guys I'm talking about they should have better prices than a stealer ship


Or use the auto parts store parts .. Shouldn't be any problem using them especially if they carry a warranty of some sort

Good luck

jdsaengine

on the Techron, one bottle every year.

My fuel g. acted up about 5yr ago, went to zero, since then never.

Vetteman Jack

I just checked my car and it has VIN 35118960 and the RPO listing shows FFS on it. So that system was installed on cars built earlier than the VIN above. Otherwise, great info to have.

vetteLT193

Techron it for a couple tanks. two bottles of techron or one bigger bottle per tank. It may take a couple tanks to get it back. After it comes back stick to the same gas station.

luke87gt

I notice you show two vin numbers? Based on your feedback:

35111542 or greater requires you to drop the tank
35222542 means new fuel system

Are you saying that if the vin occurs between these two numbers you have the old fuel system AND you still have to drop the tank?

My vin is 35114XXX, so I'm between these two numbers you provided.

Also, I'm still hoping someone can steer me to a recall#/TSB for this.

In the meantime, I'll still try the Techron for a couple more tanks.



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Lastly, what is RPO mean?

luke87gt

Thank you for the clarification on the VIN as well as the RPO (I'll look it up in my glovebox later today). It looks like I have the new FFS system however based on your feedback.

It would be helpful if someone could provide the part numbers for the fuel sending units for both the pre VIN 35111542 and post VIN 35111542.

Or maybe the solution for the pre VIN 35111542 folks is to order based on 2002 model year and us post VIN 35111542 folks is to just look up based on a 2004 model after confirming the RPO code?

I assume z06 and non-z06 is the same when it comes to these fuel sending units?

Chris Edwards

Luke I hope you find a simple solution! Those late 03 and 04 fuel systems sound like a pita... Luckily mine has not acted up yet but I imagine it will at one point.

andrec10

Techron techron techron techron techron
Techron techron techron techron techron
Techron techron techron techron techron
Techron techron techron techron techron
Techron techron techron techron techron
Techron techron techron techron techron
Techron techron techron techron techron

Road Runner

Since 2000 when I drove the vette off the showroom floor my gas gage has 'suddenly drop to zero' a half a dozen t1mes. In fact, it happened AGAIN this morning on the way to work. Techron my friend is the easy way to solve the problem - but its not the solution, only a temporary fix.

luke87gt

Gentlemen, I'll give the Techron a shot by filling a 20oz bottle of Techron Plus during the next three tanks.

I'm hopeful it helps and if not, I'll have to move on to looking at sending unit replacement.

Will keep you all updated. So far (knock on wood) this is the only issue I see with my new z06.

Luke

joeflyer

The TSB for the fuel-guage problem is 010604022. It was a software update. Had it done in 2004, and the drop-to-zero problem never came back.

luke87gt

Guys one more question for my own reference:

In order to drop the tanks on a 2003.5-2004, what else needs to come out first?

luke87gt

Well guys, I looked at my RPO codes on the inside of the glove box and I do not see the "FFS" anywhere despite my 2003 vin being vin is 35114XXX

8VETTE7, I wonder if you may have any thoughts on this?

Chris Edwards

Luke, has the techron remedied the issue?

Sent from my iPhone using IB AutoGroup

guido7834

Happened to me a couple times a few years back. Couple treatments and it hasn't come back.

CaliforniaJack

You need to add some Techron concentrate to clean up the existing sulphur deposits. If you use either Chevron or Texaco fuel, it has Techron in it and you should never have the problem again (As long as the problem is sulphurization of the fuel level senders).

bkalkwarf

One more vote for techron, and some patience. This issue is annoying, but the aforementioned formula worked for me. Oh yeah, use top-tier gas too.

I also found that using StaBil over the winter helps keep the issue from occurring in the spring.

vette48

Hi; If you are using Sunoco gas quit using it.. Sunoco has the highest sulphur content which causes the fuel gauge drop. As told use chevron or Texaco fuels. Do use techron a few times before any serious work on the tank and sending units. Don't be afraid to over dose a little bit with the techron it wont hurt anything.. It fixed my gauge after about 4 or 5 tank fills. good luck

DDaaryl

Techron is FM (friggin magic)

When my 02 vert acted up I added a 20 oz bottle to my tank when 5/8 full and drove two miles and it started working. That's why I call it FM and add it twice a year now