Fuel tank problem - 986 Forum - The Community for Porsche Boxster & Cayman Owners

stunt · 05-11-2005, 12:58 AM

Hello i have a problem with my fuel indicator,when i leave the car under the sun after i sign me the full... do you know where is the tank on the boxter, i think is a problem of the one way valve for the gas of the tank but i don't know were is the tank and the valve...
Help mee thank you

99-Boxster-MK · 05-11-2005, 04:39 AM

The tank is behind the dash.

Mike

RandallNeighbour · 05-11-2005, 06:03 AM

Stunt, there is also a problem with the hoses getting tangled inside the tank near the sending unit. When this happens, the gauge may not read full when the tank is indeed full. I cannot tell from your post if this is your problem or not... This is the problem with my boxster and I am having my mechanic work on it to simply put plastic tie wraps around the hoses to keep them from getting in the way.

My mechanic moonlights out of his home garage, but during the day he works at a dealership. He tells me that people come in with gas gauge problems all the time and it's usually something he fixes with a tie wrap in an hour or so... but the service attendant charges the customer for 4-6 hours of labor to "remove and adjust" something, just because the rate book says that's what should be charged.

stunt · 05-12-2005, 08:53 AM

ok when i take the car the indicator is always full, after ten minutes appear the really level of gasoline...
I don't understand how is the problem, i think i need to access the tank do you have same instruction to access the tank?
Thank you

clubhead · 05-14-2005, 02:10 AM

Quote:

Originally Posted by stunt

ok when i take the car the indicator is always full, after ten minutes appear the really level of gasoline...
I don't understand how is the problem, i think i need to access the tank do you have same instruction to access the tank?
Thank you

I've asked this before at renntech.com. The fuel tank opening is located under the batt. You need to remove the batt and the plate underneath it. You should be able to see it once you've done that. This is only to access the fuel tank opening where the fuel pump is though..... not to remove the entire fuel tank.

stunt · 05-14-2005, 07:46 AM

do you have scheme for opening the tank and the level indicator, sorry for the english

clubhead · 05-15-2005, 07:36 PM

Quote:

Originally Posted by stunt

do you have scheme for opening the tank and the level indicator, sorry for the english

Sorry, I don't have that. I just wanted to locate the fuel tank opening and that's what I was told. Left the reat to my mechanics....

ctbmj · 05-28-2005, 08:35 AM

I have a 2003 986S purchased in the U.K. If the fuel gets low and 'Check Fuel' warning comes up and I then re-fuel to full, the gauge does not re-set when I drive off, and the 'fuel remaining' figure on the OBC continues to drop until it becomes blank (indicating dangerously low). Sometimes the gauge resets itself to where it should be some time later in the journey, but usually this doesn't happen until the next time I drive the car from cold.

Turning off the ignition and restarting, as recommended by the local OPC does nothing. Otherwise, they have no suggestions. Most likely suspect seems to be tank sender (sticking float?) or signal conditioning software. Could it be cables in tank mentioned already in this forum? Anyone else had this?

Many thanks for any help.

Tool Pants · 05-28-2005, 09:20 AM

There is a bulletin for your year. There are pipes in the tank and the float can sometimes get hung up on them after refueling. They are supposed to tie the pipes out of the way. Your OPC should know this.

RandallNeighbour · 06-12-2005, 06:34 PM

ok, now I am frustrated.

Paid my mechanic for an hour's labor to tie wrap the cables in the gas tank to allow my fuel indicator to work properly.

Before he did this, it would only read 3/4 of a tank when full, then fall as gas was used so I could at least see when to fill up.

Got it back from him, and went to fill up and enjoy the full tank indicator for the first time since owning the car a year... it stayed at 3/4. Grrr.

Got on the freeway and sat in the heaviest bumper to bumper traffic I've endured in a very long time... and at 95 degrees outside. I looked down and my fuel level was at full! Well, I thought it had finally kicked in. Good!

Today I drove around a couple of hours and put about 110 miles on this tank of gas and it's STILL at full. Grrr.

I am guessing I should just replace the sending unit. I think I'll call LA Dismantlers and see if I can buy one used. I don't want to pay $175 for this part. It's stupid.

Toolpants, do you have any pictures of accessing the fuel sending unit so I can see them and do this little job myself? I searched renntech and didn't find any, nor did I find any here.

Tool Pants · 06-12-2005, 09:55 PM

The tie the pipes out of the way of the float level sensor is for 2002 up because Porsche changed the fuel delivery system that year when it went to the 'returnless' system. Not your year.

The sending unit is under the battery tray and held in place with a locking ring. This is the VW/Audi tool to unlock it. Your mechanic must have it.

I would not buy a used sender, if it is your sender. It could also be a problem with your instrument cluster. This is a Peter question before you start throwing money at the car.

RandallNeighbour · 06-13-2005, 05:59 AM

Thanks Jeff. Here's some info you may not remember you helped me with a year ago:

1. The instrument cluster is brand new. I had to buy one because one of the digital numbers on the speedo was out (far right one) and it bugged me so much I had to do it. The fuel gauge indicator acted the same on the original cluster as with this one, so I do not believe it's the cluster.

2. From the link below from a technical article on Pelican parts, I thought it was five bolts, not a special tool as you have pictured for the 1997. I'm not arguing with you by any means (You're the expert, not me!) but I wonder if I should just take a look anyway. This guy took out his sending unit, cleaned it up a bit and put it back in...

http://www.pelicanparts.com/techarticles/911_fuel_tank_sender_replace/911_fuel_tank_sender_replace.htm

Thoughts? Comments?

Tool Pants · 06-13-2005, 09:17 AM

The Pelican article is not for a Boxster. The tool in my pic is also shown in the Boxster shop manual. If you remove the battery tray you will see the locking ring. It 'unscrews' like the lid for a jar.

RandallNeighbour · 06-13-2005, 09:37 AM

Is it possible to unscrew the unit by hand or with another tool I might use that wouldn't chew up anything? I'd really like to do this myself.

And I'm guessing I have to remove those hoses and the electrical plug that are attached before I go unscrewing the unit, right?

Rainforest01 · 06-15-2005, 06:29 AM

Hello all!

This is my first post. I just purchased (6/10) a Rainforest Green '01. I'm having a problem with my fuel gauge and putting fuel in the car. When I first purchased the car, the gauge was at 1/4 tank. I tried to put fuel in and it kicked off after two gallons and then wouldn't take fuel at all. The pump just kept shutting off. So I figured it was full and the gauge was off. I drove about 125 miles and it ran out of gas on the PA turnpike! I put a gallon of fuel in and it started right up. I went to the pump and was only able to put another 3.25 gallons in. This means the car ran out of fuel with over 10 gallons in the tank? Is there a problem with the pick-up tube?
I actually have the receipts from the past owner and the trouble with putting fuel in the car has been addressed twice before. They fixed a crimped vent tube, realigned the fuel filler neck. They also pulled out the fuel pump and reinstalled.

Anyone else have this problem or can shed some light as to what the solution is?

RandallNeighbour · 06-15-2005, 11:37 AM

Rainforest, I say take it back to the place that did this work and ask them to fix it under warranty. I would imagine the problem lies in a vent tube blockage... the tank can hold 16 or more gallons of fuel and would have no blockage unless the vent tube was clogged.

If the vent tube has become crushed again and they won't do it under warranty, you'll have to get to the bottom of whatever is crushing that tube.

In the mean time, I'd try filling up, waiting ten minutes with the cap off and try filling up some more. You might be able to fill the tank this way, a little at a time.

What a very odd problem. Do come back to this thread to tell us what you discovered as the root cause and what parts were replaced and how much it cost.

mccarthy · 11-20-2006, 12:57 PM

Quote:

Originally Posted by ctbmj

I have a 2003 986S purchased in the U.K. If the fuel gets low and 'Check Fuel' warning comes up and I then re-fuel to full, the gauge does not re-set when I drive off, and the 'fuel remaining' figure on the OBC continues to drop until it becomes blank (indicating dangerously low). Sometimes the gauge resets itself to where it should be some time later in the journey, but usually this doesn't happen until the next time I drive the car from cold.

Turning off the ignition and restarting, as recommended by the local OPC does nothing. Otherwise, they have no suggestions. Most likely suspect seems to be tank sender (sticking float?) or signal conditioning software. Could it be cables in tank mentioned already in this forum? Anyone else had this?

Many thanks for any help.

yes i have exactly this problem. have you found a fix?

thanks

mark

CJ_Boxster · 11-20-2006, 01:56 PM

Quote:

Originally Posted by RandallNeighbour

Is it possible to unscrew the unit by hand or with another tool I might use that wouldn't chew up anything? I'd really like to do this myself.

And I'm guessing I have to remove those hoses and the electrical plug that are attached before I go unscrewing the unit, right?

Impossible by hand, when i did my feul pump replacement, I used a LONG flat blade screw driver... sorta like a Snap on Breaker bar and a hammer, I would tap the top of the screw driver with the hammer while the tip of it was on the cap, slowly turning it with every hit i make.

CJ_Boxster · 11-20-2006, 02:00 PM

Also something to remember when removing the hoses from the top of the lid. One of the 2 hoses that point down into the tank, once disconnected will start to spray out about a cup of high pressure fuel until its relieved its pressure. If you look at the picture above, its the hose with the green marking below it.