Welcome to Bimmerfest -- The #1 Online Community for BMW related information! Please enjoy the discussion forums below and share your experiences with the 200,000 current, new and past BMW owners. The forums are broken out by car model and into other special interest sections such as BMW European Delivery and a special forum to voice your questions to the many BMW dealers on the site to assist our members!

Please follow the links below to help get you started!

Go Back   Bimmerfest - BMW Forums > BMW Model Discussions > 7 Series / 8 Series > 7 Series - E38 (1995 - 2001)

7 Series - E38 (1995 - 2001)

Reply
 
Thread Tools Display Modes
  #1  
Old 03-15-2013, 12:57 PM
J1w1 J1w1 is offline
Registered User
Location: South Africa
 
Join Date: Mar 2013
Posts: 7
Mein Auto: 740i 1999 model
1999 bmw 740i fuel gauge

When my car gets between 10 - 20 liters on gauge and the range shows 155km, I suddenly run out of fuel. Do I have a faulty gauge. What could be the problem. I can not trust what the fuel range is.
Reply With Quote
Ads by Google
  #2  
Old 03-15-2013, 04:12 PM
chrisn7 chrisn7 is offline
Officially Welcomed to the 'Fest
Location: Huddersfield, West Yorks
 
Join Date: Oct 2011
Posts: 486
Mein Auto: 750iL
The fuel tank in these cars is saddle design - therefore it has contents in the left and right sides. The place to start is via the 'secret' service menu, accessed via the dash display. When you locate Test #06 you would normally see left, right, total contents. My guess is that one of the 1st two will be zero, suggesting a faulty tank sensor
Reply With Quote
  #3  
Old 03-15-2013, 04:20 PM
jitsjaf2009 jitsjaf2009 is offline
Officially Welcomed to the 'Fest
Location: Hemet, Ca
 
Join Date: Aug 2012
Posts: 451
Mein Auto: 1995 325i Convertible
I was going to suggest the tank level sensor, but did not know about the R - L - T. I can go to bed now...I learned something new. Thanks
Reply With Quote
  #4  
Old 03-16-2013, 03:36 AM
J1w1 J1w1 is offline
Registered User
Location: South Africa
 
Join Date: Mar 2013
Posts: 7
Mein Auto: 740i 1999 model
Thank you

Quote:
Originally Posted by chrisn7 View Post
The fuel tank in these cars is saddle design - therefore it has contents in the left and right sides. The place to start is via the 'secret' service menu, accessed via the dash display. When you locate Test #06 you would normally see left, right, total contents. My guess is that one of the 1st two will be zero, suggesting a faulty tank sensor
Reply With Quote
  #5  
Old 03-16-2013, 07:09 AM
J1w1 J1w1 is offline
Registered User
Location: South Africa
 
Join Date: Mar 2013
Posts: 7
Mein Auto: 740i 1999 model
Test number 6

Quote:
Originally Posted by chrisn7 View Post
The fuel tank in these cars is saddle design - therefore it has contents in the left and right sides. The place to start is via the 'secret' service menu, accessed via the dash display. When you locate Test #06 you would normally see left, right, total contents. My guess is that one of the 1st two will be zero, suggesting a faulty tank sensor

Hi, can you tell me how to run the test. I got as far as to push the two buttons on the dashboard that normally resets the counter. I keep the two buttons in for a couple off seconds and then the test menu appears, I scroll to test 6 and it says locked. Must I have a computer connected to the car or can you tell me what levers/buttons to use to start the test.
Reply With Quote
  #6  
Old 03-21-2013, 03:24 PM
chrisn7 chrisn7 is offline
Officially Welcomed to the 'Fest
Location: Huddersfield, West Yorks
 
Join Date: Oct 2011
Posts: 486
Mein Auto: 750iL
Turn on ignition / Press & hold right button 10 secs > Check control OK > Test Nr01 / Press left button briefly > Chassis no > add these together / Press right button repeatedly till Test Nr 19 / Press left to see 'Lock on' / Press left repeatedly till Chassis number addition reached / Press right to see Test Nr 01.

Press right repeatedly to see several pieces of info' all under Test 01. Once it loops back to the Vin, you've seen all Test 01. Press left button repeatedly now to see Test 02, 03, 04, 04, 05 in turn as these only have one line of data each. At Test 06 see the info required (Write it down). Press right button, and note teh 'Phase' number: Phase 1=tank sensors good; Phase 2=sensor faulty; Phase 3= sensor faulty one or more; fuel gauge reads zero.

If you have a faulty sensor, replace, then go to Test 21=Reset? which you have to do when a sensor is replaced.

Unfortuately you cannot go backwards, so you will have to go through the tests to 19 to 'Lock on' again, though some people leave it unlocked for quick access for 07 and 08
Reply With Quote
  #7  
Old 03-23-2013, 05:18 AM
J1w1 J1w1 is offline
Registered User
Location: South Africa
 
Join Date: Mar 2013
Posts: 7
Mein Auto: 740i 1999 model
Question Test 6 done

Hi I finally did the test and something strange is happening. My car just died again and I had 28L left in the tank. Here are the results from my first test.
#6 TNK:19.1/9.5/28.6L
I then put additional fuel into the car and did a second test.
#6 TNK:19.1/18.3/37.4L
Clearly the second test seems to be more accurate. I also noticed that if I rev the car fast up to 4000 rpm then it spatters a little and as the rev drops it back fires a little.

Any suggestions regarding the fuel sensors and back fire?
Reply With Quote
  #8  
Old 03-24-2013, 03:48 AM
chrisn7 chrisn7 is offline
Officially Welcomed to the 'Fest
Location: Huddersfield, West Yorks
 
Join Date: Oct 2011
Posts: 486
Mein Auto: 750iL
Please avoid back-fires as these are not good for the cats.
Are you saying that the car cuts out when the tank contents are as the first reading? This is suggesting that the l/h sensor is faulty as the reading didn't change when you added fuel. Have you run any diagnostics?

You might find the attachment interesting. This just relates to the tank-there a whole load more to do with the vent system too.
Attached Files
File Type: pdf E38_Fuel_Supply_System.pdf (102.7 KB, 39 views)
Reply With Quote
  #9  
Old 03-24-2013, 04:21 AM
J1w1 J1w1 is offline
Registered User
Location: South Africa
 
Join Date: Mar 2013
Posts: 7
Mein Auto: 740i 1999 model
Thanks

I drove the car 22km and it started to play up again. When I took the reading again from test #6 I got the following values
26.1/4.2 my concern is leaning towards the side where the fuel pump is because the levels fluctuate drastically.
Reply With Quote
  #10  
Old 03-26-2013, 06:26 AM
chrisn7 chrisn7 is offline
Officially Welcomed to the 'Fest
Location: Huddersfield, West Yorks
 
Join Date: Oct 2011
Posts: 486
Mein Auto: 750iL
Well it seems changes in fuel levels are being recorded, so the sensors must be ok. The problem at 4k rpm could be fuel starvation when the engine is under load. Has the fuel filter been replaced or is still the original? I would still go for some diagnostics though to get a lead on this..
Reply With Quote
  #11  
Old 04-11-2013, 02:49 AM
J1w1 J1w1 is offline
Registered User
Location: South Africa
 
Join Date: Mar 2013
Posts: 7
Mein Auto: 740i 1999 model
Fuel Pump Replaced

Hi, I found the problem to my car cutting out with 25L left in tank, we fitted a secondhand tank and noticed that the fuel pump inside the tank was not the original and was loose. It was causing a vacuum. I fitted an original BMW fuel pump+housing+sensor and the car seems to idle better and drive a little smoother than before. I have a new problem. When I reach 160km/h then the car hits a flat spot, meaning the car does not really produce more speed or power, it drops off. What can this be? I had this before with the old non standard fuel pump and now I have it on the new/secondhand original pump. I also hear a pitching up and down sound like a car alarm coming from the fuel tank which I believe is from the Check Valve. Can this affect my power on 160km/h, what would you suggest, air filter is new, fuel filter is clean and good. Maybe Spark plugs, Coils, etc....
Reply With Quote
  #12  
Old 04-11-2013, 05:54 AM
chrisn7 chrisn7 is offline
Officially Welcomed to the 'Fest
Location: Huddersfield, West Yorks
 
Join Date: Oct 2011
Posts: 486
Mein Auto: 750iL
Glad to hear you have finally isolated the main problem-not something easy to diagnose on a forum!

Your 160 kph is almost exactly 100mph. Is the top speed govered for SA? Its 155 mph for UK, Germany and 120 mph (I think) for USA. Just a thought...
Reply With Quote
  #13  
Old 04-11-2013, 05:58 AM
J1w1 J1w1 is offline
Registered User
Location: South Africa
 
Join Date: Mar 2013
Posts: 7
Mein Auto: 740i 1999 model
Not sure

I can I check this?
Reply With Quote
  #14  
Old 04-11-2013, 07:50 AM
jitsjaf2009 jitsjaf2009 is offline
Officially Welcomed to the 'Fest
Location: Hemet, Ca
 
Join Date: Aug 2012
Posts: 451
Mein Auto: 1995 325i Convertible
I have had mine (just as an acceleration test) to 115 mph, and then I backed off. It got there really fast and steady...I was impressed with (at that time) my 'new' 1995 740i a few months back.
Reply With Quote
Reply

Bookmarks


Forum Navigation
Go Back   Bimmerfest - BMW Forums > BMW Model Discussions > 7 Series / 8 Series > 7 Series - E38 (1995 - 2001)
Today's Posts Search
Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off



Forum Jump


All times are GMT -7. The time now is 08:17 AM.


Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2014, vBulletin Solutions, Inc.
© 2001-2011 performanceIX, Inc. All Rights Reserved .: guidelines .:. privacy .:. terms