Jump to content

The RennTech.org community is Member supported!  Please consider an ANNUAL donation to help keep this site operating.
Click here to Donate

Welcome to RennTech.org Community, Guest

There are many great features available to you once you register at RennTech.org
You are free to view posts here, but you must log in to reply to existing posts, or to start your own new topic. Like most online communities, there are costs involved to maintain a site like this - so we encourage our members to donate. All donations go to the costs operating and maintaining this site. We prefer that guests take part in our community and we offer a lot in return to those willing to join our corner of the Porsche world. This site is 99 percent member supported (less than 1 percent comes from advertising) - so please consider an annual donation to keep this site running.

Here are some of the features available - once you register at RennTech.org

  • View Classified Ads
  • DIY Tutorials
  • Porsche TSB Listings (limited)
  • VIN Decoder
  • Special Offers
  • OBD II P-Codes
  • Paint Codes
  • Registry
  • Videos System
  • View Reviews
  • and get rid of this welcome message

It takes just a few minutes to register, and it's FREE

Contributing Members also get these additional benefits:
(you become a Contributing Member by donating money to the operation of this site)

  • No ads - advertisements are removed
  • Access the Contributors Only Forum
  • Contributing Members Only Downloads
  • Send attachments with PMs
  • All image/file storage limits are substantially increased for all Contributing Members
  • Option Codes Lookup
  • VIN Option Lookups (limited)

Recommended Posts

I’m having a weird ‘fuel thing’ with my 2001 Porsche 911… So, I’ve been thinking it gets terrible gas mileage, compared to my 986 Boxster. I expected slightly less, but, it seems pretty bad. Now, I can’t help but wonder if there’s actually something amiss about it.

 

When I fill the tank completely—and I mean ‘topping it off’ to get every last drop in, my fuel gauge usually looks like this (see the first picture, 01).

 

That picture was taken immediately after starting the car after filling up the tank (I was still at the pump). There have been occasions where the needle has gone all the way to just slightly past the 4/4 mark (just like the Boxster always does), but it usually lands below as seen in the photo.

 

However, today I was down to the warning light coming on telling me I’m low on gas. I stopped to fill it up and it only took about $30 worth. That’s odd, with gas prices here and filling up an almost empty tank, that should have been between $44 and $48 (that's what the Boxster runs). I tried to top it off but it wouldn’t take any more, as if the tank was full.

 

So, I got in the car and started it, and (just like before) this picture was taken immediately after starting the car after filling up the tank (I was still at the pump) - (see the second picture, 02).

 

Just barely over half a thank.

 

Any idea what could be going on with this?

01.jpg

02.jpg

Link to post
Share on other sites
    You can remove these ads by becoming a Contributing Member.

  • Moderators

Given the fuel system management using calculated values, it is recommended to refuel the car with the ignition off in first place.

Link to post
Share on other sites
  • Admin

The fuel tanks and plumbing are very different between the C2 and C4 due to the front drive axle in the C4.

C4's historically have more fuel tank issues (mainly with calibration) because their are two sides to the fuel tank - a saddle bag layout.

 

If your tank is not filling all the way then I would suspect a crimped fuel fill hose or one of the other lines for vent return.

 

fuel tank 2WD.png

Link to post
Share on other sites

does gas actually flow easily into your gas tank?

there is a known issue with the vent valve not opening and preventing tanks from easily filling.

If you are getting a good flow of gas from the pump, check your fuel sender, and then check the fuel gauge.

I think, I hope this is wrong, but I remember reading that if a gauge is faulty the entire instrument cluster needs to be replaced.  Loren?  RFP?

there are several articles on the filler valve issue, the search engine will be your friend.

good luck

Link to post
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

  • Similar Content

    • By Trevar
      I am looking for some help/advice on how to remove my speedo gauge face. I have everything removed but can’t figure out this last piece in the center. Thanks in advance. 

    • By Graeme Tate
      I hate my pig but I love my pig, can anyone please help me before I send it for scrap. Over the space of the last 4 years of ownership my car has been in the Porsche dealers for 2 years in total with suspension problems, to cut a long story short this is now sorted and was due to a faulty replacement air bag being fitted. Moving on after 3 months of (almost) trouble free motoring this is what’s happening now and would love some advice as the closest porsche dealers is over 200 miles away from me.

      When I picked up the car from Porsche  it ran out of petrol before I got to the garage at the end of the road and although I filled it up it  the engine warning light remained on I assumed this was just fuel related and drove home with it on and reset it when I got home.
      Wind on a few weeks and the engine light came back on and gave me a camshaft position sensor error p0016 so I sent the car to my local Porsche mechanic who changed out the sensor and did a full service on the car including plugs filter oil etc etc. All this time the car has been running fine but as I wanted the sensor light out it was changed. However after changing it out the light came back on almost straight away. The car has been a bit sluggish to start sometimes and sometimes on pulling away from a stop has also been hesitant. 
      This was about 3-4 weeks ago and now it is worse again, at tickover it’s noisy, it doesn’t like acceleration and is running really rough although if you are going over 50mph it doesn’t have a problem and seems to run fine. The EML is now flashing rather than being a solid light. I attach a video of it running.
      Any thoughts would be a help before I decide to get it hauled back across again 



      Sent from my iPhone
    • By Pxwguad
      Hi Guys, I am a proud owner of a 2010 Porsche Cayenne Base model and I have been having a intermittent Engine hesitation issue. the following is a detailed issue of whats been happening, any suggestions that would help resolve this is appreciated.
       
      About a month ago I was coming back from Roosevelt lake ,AZ which is about 3 hours from Tucson, it was a hot day 113deg, I was already in town and the gas gauge read about 1/8 of a tank and I was starting to move from a light when all of the sudden it felt like the engine stalled and came back on for a second then it did it again and my CEL came on.
       
      I thought maybe my gauge was off and i was running out of fuel so i found the nearest gas station and filled up, I drove home and connected my car to my Icarsoft Computer and it was showing error P2293 Rail Pressure Control, I cleared the error and decided I would drive the car and see if it would happened again, Two months and hundreds of miles of mixed city and highway driving went by without a hitch.
       
      Last week I had to go to LA so I packed up the car (4 passengers and luggage) and headed out. About two hours in on I8 right before Yuma it was 114 degrees outside and  I was cruising at about 85 MPH, the gas gauge read about 5/8 of a tank all oil and coolant temps were normal when all of the sudden the hesitation came back, it would run normal then hiccup then run normal, ect.. and the CEL came back on, this went on for about 20 minutes but I was still able to maintain 80-85 MPH.
       
      After 20 minutes of this we decided to pull into a gas station and fill the tank with gas to see if anything would change and wouldn't you know that after filling up and setting off again over the mountain pass towards San Diego the car ran without a hitch, we averaged 77 MPH all the way to LA, but we would stop to fill up whenever the gauge read 5/8. after a couple of hours the CEL turned off on its own.
       
      On our way back to Tucson we decided to fill up in San Diego and not fill up until it started to act up, and to my surprise the car once more ran flawlessly.
       
      We didn't fill up until the gas low warning chime came on in Marana, AZ. The highest temperature this day was 104 deg. We filled the tank and made it home without incident. The next day I connected my car to my Icarsoft computer and it was showing the following error codes: P2293 Rail Pressure control, P0300 Random/multiple cylinder misfire detected, P0301 cylinder 1 misfire detected, P0303 cylinder 3 misfire detected.
       
      Could this be ambient temperature related? Vapor lock at high ambient temps? If it was the fuel pumps you think it would have failed again on the way back, right?
      This has to be happening to other people with 2007-2010 Cayenne Base models. Any input will help.
       
      Thanks in Advance.
       
      Sincerely;
      Paul
    • By longrowe
      I have a 1998, ROW C2. Over the past two weeks I have noticed that the fuel gauge is not reading correctly. The gauge will read high (3/4) but as I drive, the gauge will slowly drop to the correct reading over about 15 minutes. As the car sits, either at work for the day or in the garage overnight, when I go to start the car, the gauge will read over 1/4 tank higher than when I shut it off. Then, as I drive, it will drop to where I think it should be (or remember where it should be). I plan to pull the sender this weekend and check the connections, but I don't think it is the float as why would it rise while the car is turned off? Is it possible to troubleshoot the cluster gauge? I have a Durametric so I will attempt the fuel level calibration when I have pumped down the tank. Or am I just fooling myself and the gauge is bad?
    • By dbmies
      I have a 2000 996 with 107k miles
      I had the AOS replaced about 20k miles ago.  I replaced my crank position sensor about 5k miles ago to prevent hot start issues.
      For the third time in about 3 months (I don't drive every day)  my 996 wouldn't fire after filling up with fuel. I had been having issues with gas station pump nozzles shutting off prematurely - in California where we have the vapor recovery nozzles that aren't good for topping off the fuel.  But the only way I could get my tank close to full was to fill it very slowly.
      The first time I had the starting trouble after fueling, the car started up normally, but as soon as I pulled out onto the street and stopped at a traffic light the engine died - as if the fuel pump had stopped. When I tried to restart, the engine cranked but with no signs of fire.  I pushed it back into the gas station and after 15 minutes with tow truck on the way I tried one more time - with the pedal floored - and it started after about 5 seconds of cranking.  
      The second time about a month later, I was far from home and it wouldn't start at all after refueling (again after topping off).  I found something on the internet that said you can over-fill the tank and get fuel in/near the charcoal canister - causing some sort of safety shut-off to protect the canister from damage.  So I tried to siphon some gas out but my siphon tube went in the filler pipe at least 36 inches without getting wet I figured over-filling was the issue. Eventually I got frustrated, cranked with wide open throttle and after about 5 seconds it started.
      I replaced the fuel line vent valve to fix the premature nozzle shut-off hoping it would fix both issues.  After doing so I drove to the station and filled up with fuel - no premature shut-off of the nozzle this time.  But again the car wouldn't start.  Without hesitation this time I cranked with wide open throttle and it started after about 5 seconds.
      I found this link on the internet among others saying the cool fuel can prevent a worn piston from building pressure - http://www.fixya.com/cars/t3860084-after_fuel_fill_cap_removal_2003_996
      Think my next trial will be to replace the fuel pump unless anyone has a better idea?  Should I test the pump pressure first before replacing?
      It isn't throwing any fault codes - I'm getting some occasional idle surge with the engine is hot - just started recently.
      Last I checked (after the first incident) nothing jumped out at me on the Durametric.
      All advice and DIY links appreciated. Thx
×
×
  • Create New...

Important Information

We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue.