Fuel Gauge

I am having trouble with the fuel gauge on my 2000 Chevy Venture. It has a mind of it's own! :shakehead The only time it reads accurately is when you fill it up. It sometimes even behaves like the speedometer, going higher when you accelerate. It has me puzzled. We also no longer enjoy the same mileage and power that we did when we purchased it second hand last year. I have been told that it could be from using Shell fuel in the past (additive problem for GMs). Is this possible? Any suggestions/advice out there? :feedback:

some one is blowing smoke up your tail pipe, if you know what i mean. A Shell Additive???? I don't think so. that would not have anything to do with a sensor in the tank.

There is some truth to what you were told. Your problem is probably the fuel level sending unit card contacts gone bad. It is somewhat of an old design potentiometer with spring contacts on the float arm. Some fuels or especially additives are known to attack the card, harming the connection.

Had the same problem. Took about 2 hours to r&r the tank. The fix was to clean the contacts on the sending unit. I have a power point with additional info to do the job if any one is interested. The readings from the sending unit were 40 ohms empty and 250 ohms full after cleaning. Before they were all over the place.

I had the exaxt same problem....it started around 110,000 KM....was told it was Shell gas as well. I was SOLD a cleaner from GM to correct the problem, and it did fix it.

That's absolutely truth, read the following article:

http://www.nola.com/business/t-p/index.ssf?/base/money-0/108711052227870.xml

Had the same problem. Took about 2 hours to r&r the tank. The fix was to clean the contacts on the sending unit. I have a power point with additional info to do the job if any one is interested. The readings from the sending unit were 40 ohms empty and 250 ohms full after cleaning. Before they were all over the place.

My 2000 Venture has the same problem. I took the tank out, but I wasn't quite sure how to get to the sending unit. If you still have that Power Point, I'd sure be interested in seeing it.
Thanks,
-Kurt

I also have the same issue. What cleaner did you get from GM and do you still have the PP presentation?

I had the exaxt same problem....it started around 110,000 KM....was told it was Shell gas as well. I was SOLD a cleaner from GM to correct the problem, and it did fix it.

I have the same problem with my 2000 Venture. I did some online searching & ran across several articles mentioning sulfur in the gas. I also read about a "fix" from GM that could be poured in the tank to clean the contacts. I went to my local dealer to buy the "fix" & they laughed at me. They said the only "fix" was to replace the sending unit. Do you recall the name or part number for this stuff?

Glad there are no Shell stations near me! My '99's gas gauge has been balls-on accurate (it's an industry term) for 140,000 miles!

Bumpity bump, bump

Bump

I had the EXACT same problem as described in the original post, only at about 60,000 mi. I never heard about a gas additive causing problems, but I suppose that could make sense. I was not able to repair the broken sending unit, as the "fingers" on the level float were all broken off.

Took about 45 mins to remove gas tank. From there the sending unit is a screwed on cap on the top of the gas tank. Removed and replaced sending unit (new sender about $75 from dealer; BONUS you get 2 in the package, but with different connectors. You could remove the connectors that DON'T match yours and alter that sending unit to work with your car for next time).

Total repair time; about 2 hours.

Had the same problem. Took about 2 hours to r&r the tank. The fix was to clean the contacts on the sending unit. I have a power point with additional info to do the job if any one is interested. The readings from the sending unit were 40 ohms empty and 250 ohms full after cleaning. Before they were all over the place.
I have a 2001 Montana with the same problem. I would be interested in receiving any info to help me correct it. By r & r do you mean you have to remove and replace the sending unit in the tank?
Alex

When I had problems with my gas gauge (2002 Venture)
I added gasline cleaner (some off the shelf stuff) It worked fine - $5

At first I was told I would have to replace the senors on the tank - $300

Advice: Try the easy, cheap solutions first, what do you have to lose ?

When I had problems with my gas gauge (2002 Venture)
I added gasline cleaner (some off the shelf stuff) It worked fine - $5

At first I was told I would have to replace the senors on the tank - $300

Advice: Try the easy, cheap solutions first, what do you have to lose ?
I have the same problem with my Yr 2000 Pontiac Montana and I would like to try that same solution. Just want to make sure what exactly gasline cleaner is or better still, the exact product name. How many applications did it take to fix your problem?

Gasline cleaner is not the same as the gasoline treatment products used to clean fuel injection systems? I heard some reports on those gasoline treatment products may cause some other engine problems.

Hi,
Do you remember which gasoline cleaner have you used?
I have the same problem with my 2000 Venture.
Dworakow





When I had problems with my gas gauge (2002 Venture)
I added gasline cleaner (some off the shelf stuff) It worked fine - $5

At first I was told I would have to replace the senors on the tank - $300

Advice: Try the easy, cheap solutions first, what do you have to lose ?

I picked it off the shelf a the shell station.
It was next to the fuel injection cleaner
I'll try and find its name

ah.. found it
I stopped by the Shell station today and bought another one. It's Pennzoil Gas Treatment. It's the gas cleaner that "fixed" my gas gauge on my 2002 Venture. One more thing. I believe the root cause is the ethanol blend gas (10%) that I have been using. Many of the fellas from work, no longer use blended gas because of poor gas mileage and other gum up problems they encountered. I am tracking my gas mileage now to try and prove/disprove the theory as many other people believe blended gasoline is fine. Maybe it depends on the car ?

I noticed that throughout this thread a cleaner is added to correct an erratic fuel gauge. Can someone suggest what cleaner should be used?

Thanks.

Some of the people used super concentrated STP cleaner, others preferred Shell products. However, don't take it for sure, do your own research at the forum.
Personally, I tried STP, it helped a little.
Good luck





I noticed that throughout this thread a cleaner is added to correct an erratic fuel gauge. Can someone suggest what cleaner should be used?

Thanks.

The early carbon wipers were made in such a way that higher sulfer concentratiosn attacked it, essentially wearing away at it until they no longer made contact or if they made contact, the resistance value would change. Dumping any type of cleaner into the take will do little lasting good other then lightening your wallet. The sensors have since been redesiged so that it shouldn't be an issue. This isn't just an issue on our van or even with just GM. Other vehicles have been effected by this as well.

Replacing the sensor isn't that hard. It takes an nearly empty tank and an hour or two to drop it, unscrew the ring, lift out the pump/sensor and then reverse the procedure. You can get the sensor seperate from the dealership, the whole fuel pump/sensor assembly OEM, or pay slightly more then the OEM sensor alone and get an aftermarket pump/sensor assembly.

Its been now six months (Jan - June) and my Venture's fuel gauge has been working fine since I added the Penzoil gas treatment. I'm not sure if my problem/solution is unique I'm just adding my two-cents. I'm no mechanic, engineer nor fuel chemist, just damn glad I found a cheap fix to a problem. Now if you want to talk about the manifold gasket, rear wiper motor, peeling paint, exploding side window and loose transmission on a van thats not even 3 years old......... I could talk your ear off over a few beers.

Did any of you while the guage was not working correctly experience any other problems with the van?? The van is working/driving/shifting fine as long as the guage is working but when it goes south the engine light goes on and the van starts working weird, shifting down like kickdown ect.
Thanks
Andy

Did any of you while the guage was not working correctly experience any other problems with the van?? The van is working/driving/shifting fine as long as the guage is working but when it goes south the engine light goes on and the van starts working weird, shifting down like kickdown ect.
Thanks
Andy

Nope, Shifting is one thing that my Venture seems to manage ok.
(see above gripe with my Venture)
I forget to mention that the electrical for my trailer doesn't work right and the right mirror drifts. At least the AC worked today if was HOT !!(touch freakin wood).

When my fuel guage went south I immediately checked the voltage on the system and it was dead on balls accurate (a real technical term). It's just the fuel guage for me.

Sag.

Check this out:
http://www.trademotion.com/partlocator/index.cfm?action=getLocator&siteid=213800&chapter=DP1009&appSectionid=3&groupid=10009&subgroupid=20124&componentid=60648&make=6&model=Venture&year=1999&catalogid=1

I added STP gas treatment to a half-full tank and let it sit overnight. Presto -- the problem was fixed in the morning.

Sag.

I've been trying to fix this problem with my 1999 Trans Sport for some time now. The fuel gauge will read full when the key is first turned on then within a minute it will fall to empty and turn the fuel light on. This problem happens every time and regardless of the amount of fuel in the tank.
I thought it was a sending unit problem, so i unplugged the connector from the tank to test it and after grounding the terminals i found that it would not change the reading of the gauge - so not a sending unit prob.

I traced the wires up to the dash and found nothing out of place,

I even removed the instrument panel and found nothing out of place.

I called the dealer and some local shops and none can offer me any ideas as the what the problem is. Anyone got any ideas?

The gauge on your dash is controled by the PCM, not directly by the sending unit. As a check of the functionality, the PCM will raise the gauge to full and then drop it to empty slowly over time. When I was having similiar problems, how quickly it dropped seemed to be related to how quickly it dropped. More recent restarts would drop it quicker.

If the resistance the PCM measures is either too low (short) or too high (open circuit), it will behave like what you are having problems with.

The sending unit works by varying the resistance via a potentiometer attached to a float in the take. As the float rises, so does the resistance. Empty it should be around 40 ohms. Full it should be 250 ohms.

The first thing I would do is check the resistance across the two wires at the connector beneith the driver's seat since it is easiest to get to. It should be between 40-250 depending on the level of fuel. If it is, then it's not the sending unit. If it's not, then you'll have to drop the tank to get to the connector there (or to change the sending unit anyways). It's not hard, just awkward especially if there is a signifiant amount of fuel (6lbs/gallon).

If there is no or very little resistance, you have a short, most likely at the sending unit. If you have significantly more then 250 ohms of resistance, then your sending unit may be shot. If you have infinite resistance, then you have a broken wire or a bad sending unit.

If everything test fine at that connector, go to the connector at the firewall beneith the dash. Measure the resistnace there. If you measure the same as you did with the connector under the car, then your wiring is fine there. Otherwise, your problem lies between the two connectors.

If the firewall connector is fine, check at the PCM. There is actually two connectors between the firewall and the PCM IIRC so a problem between the firewall and PCM could be between there.

I can post the pinouts of the connectors tonight if you don't have a shop manual (not a Haynes manual).

When I had my problem, it was both a faulty sender as well as a broken wire under the left foot wire loom under the dash.

Thanks a lot for the help. I need all I can get. It would seem that the problem has nothing to do with the sending unit because the gauge will go from full to empty even when the connector under the seat is unplugged entirely from the tank.

Ill have to check the resistances in the wires, but once I trace the wires up to the firewall its very hard to tell which wires go where. A diagram would be really helpful

Thanks a lot for the help. I need all I can get. It would seem that the problem has nothing to do with the sending unit because the gauge will go from full to empty even when the connector under the seat is unplugged entirely from the tank.This wouldn't rule out a bad sending unit though. A broken wire AT the sending unit would act the same way. Also, if the carbon wipers were damaged enough so that they did not make contact, it would act the same way as a open circuit. Testing at the connector in the floor of the van will point you in which direction you need to look for the problem.

The problem with the carbon wipers corroding is common with many GM (among others) vehicles. They seem to wear out quickly if a high sulfer content fuel is used. I know Canada and the south has had issues with this in recent years. Wether you have had problems in Cape Verde I can't say.

Thanks. I'll try that first. The only problem with ours is that we are wary to let the tank get below one-half full because of the one time my wife ran out of gas and had to wait an hour for AAA. From what I've read Chevron makes the best fuel system cleaner. We'll see....

Had the same problem. Took about 2 hours to r&r the tank. The fix was to clean the contacts on the sending unit. I have a power point with additional info to do the job if any one is interested. The readings from the sending unit were 40 ohms empty and 250 ohms full after cleaning. Before they were all over the place.
could you please send me the power point on cleaning o0r repairing the contacts.

Thank you

could you please send me the power point on cleaning o0r repairing the contacts.You'll be waiting a while. That poster only showed up once and that was over 1.5 years ago.

The normal failure of the wipers is corrosion, and no amount of cleaning will fix that. A good electrical contact cleaner will do the job if they were just dirty, but gas is a decent solvent as it is and the sensor is constantly being bathed in it anyways.

You'll be waiting a while. That poster only showed up once and that was over 1.5 years ago.

The normal failure of the wipers is corrosion, and no amount of cleaning will fix that. A good electrical contact cleaner will do the job if they were just dirty, but gas is a decent solvent as it is and the sensor is constantly being bathed in it anyways.


You'll need to buy a new fuel pump and send unit. Somewhere in one of these threads is the actual part number for both and you can buy it at gmpartsdirect.com

First find a local garage that will do the work for you if you bring the part in yourself. This will save you on the markup they would ordinarily apply.

All told plan on spending around $400.

You'll need to buy a new fuel pump and send unit. Somewhere in one of these threads is the actual part number for both and you can buy it at gmpartsdirect.comYou can buy the sending unit seperate nowadays. I beleive the price is around $80 from the discount dealer part sites.

First find a local garage that will do the work for you if you bring the part in yourself. This will save you on the markup they would ordinarily apply.If you have some basic tools, you can do it yourself (weather cooperating). Run the tank nearly empty, loosen the clamp at the filler neck, disconnect the 3 fuel lines, then remove the 3 straps holding the tank on. A jack or some blocks of wood can help support the tank if it's not empty.

Then just loosen the ring and you have easy access to the pump/sending unit.