A8 Parts Forum  

Go Back   A8 Parts Forum > A8 D3 > D3 - Fuel and Exhausts

D3 - Fuel and Exhausts Everything to do with getting fuel into the engine, and fumes back out again

Reply
 
Thread Tools Display Modes
  #1  
Old 31st July 2016, 05:57 PM
Quattrodave Quattrodave is offline
Member
 
Join Date: Oct 2015
Posts: 53
Default Continuing fuel problems

Afternoon all.

Firstly a big thanks to all that helped me identify where the fuel pump control module was located - the garage I had it at were properly perplexed!

So, they fitted it and all was well again, for about three weeks when the day following a successful 350 mile round trip to Plymouth the car cut out again in exactly the same way as before. I managed to get it recovered to the same garage who have had it a week now and have achieved nothing. Their diagnostics is telling them there is no problem at all, everything is running fine, they left it running for an hour, all good, then when reversing out of the garage it cut out on them!!

Beaten they've just sidelined my car and have been working on everyone elses so today I jumped back in my car (they left it on the road in a trading estate!) and drove home, no problems.

Does anyone have any ideas what could be causing this very intermittent problem whereby the engine will cut out and will turn over but won't start due to no fuel delivery for about an hour but will then start up and drive fine again?

It's had a brand new, audi sourced fuel pump control module less than a month ago which was showing as faulty when it did it before. The only other thing that has happened to the car is the front plenum chamber drain holes clogged up leading to a small leak into passenger footwell but as part of getting the fuel pump module replaced this was cleaned out thoroughly and nothing has leaked since.

Any clues or ideas most welcome. Kinda at the point where if this isn't sorted and put to bed soon I'm just going to get it fixed and sell the car
Reply With Quote
  #2  
Old 1st August 2016, 12:45 PM
Quattrodave Quattrodave is offline
Member
 
Join Date: Oct 2015
Posts: 53
Default

Does anyone know roughly how much new fuel pumps would be for a 4.2 fsi? I see there's two in the tank and am just wondering if they're not hugely expensive whether it's worth just getting them both replaced (along with the fuel filter).

Is the fuel filter accessed from the top of the tank per the pumps or is it under the car where they usually are?
Reply With Quote
  #3  
Old 1st August 2016, 01:17 PM
Quattrodave Quattrodave is offline
Member
 
Join Date: Oct 2015
Posts: 53
Default

Scrub that, just seen, £210 each x 2!!

Maybe worth fully diagnosing rather than just replacing both in that case!

Damn, back to square 1!
Reply With Quote
  #4  
Old 1st August 2016, 08:25 PM
Quattrodave Quattrodave is offline
Member
 
Join Date: Oct 2015
Posts: 53
Default

So, checking on Audiworld they're suggesting that the left pump is used to prime the right pump, transfer fuel from left to right holds in the tank and to increase fuel supply at higher loads (above 3k)

So as a quick check tonight I started the car (first time) and it quickly sat down to a nice idle, but then when revving it sputtered above 3k and stopped dead at 4k.
Reply With Quote
  #5  
Old 1st August 2016, 10:21 PM
PsYcHe PsYcHe is offline
Senior Member
 
Join Date: Jan 2009
Location: Blantyre, Scotland
Posts: 4,136
Default

How much fuel is in the tank? If it's the transfer pump then it doesn't usually show a problem above 1/4 tank or so.
__________________
2010 Jag XF 3.0D Portfolio S

I know.. I know..

Reply With Quote
  #6  
Old 1st August 2016, 10:34 PM
Quattrodave Quattrodave is offline
Member
 
Join Date: Oct 2015
Posts: 53
Default

Quote:
Originally Posted by PsYcHe View Post
How much fuel is in the tank? If it's the transfer pump then it doesn't usually show a problem above 1/4 tank or so.
Just over half a tank. So you're not thinking that's the problem then?
Reply With Quote
  #7  
Old 2nd August 2016, 04:39 AM
Delboy's Avatar
Delboy Delboy is offline
Senior Member
 
Join Date: Aug 2013
Location: Lowestoft, Suffolk
Posts: 2,492
Default

There's a detailed process to test the pumps on these in the tech dump Dave.

Have a look through the D3 common fault section for the tech dump
__________________
Del

Reply With Quote
  #8  
Old 2nd August 2016, 07:26 AM
Quattrodave Quattrodave is offline
Member
 
Join Date: Oct 2015
Posts: 53
Default

Quote:
Originally Posted by Delboy View Post
There's a detailed process to test the pumps on these in the tech dump Dave.

Have a look through the D3 common fault section for the tech dump
Thanks Delboy, I'll take a nosey after work tonight.

CHeers

Dave
Reply With Quote
  #9  
Old 2nd August 2016, 02:11 PM
Quattrodave Quattrodave is offline
Member
 
Join Date: Oct 2015
Posts: 53
Default

Foudn the tech section and the pdf docs thanks.

There's a lotta specialist tools listed, of which I have none! Have printed the necessary pages and may well end up taking the car back to the garage with diagrams in hand!

Was hoping it was something I could check!

May still have a look tonight and see if there's something I can do to make myself feel a little more useful (hate relying on garages - especially when they're busy & slow & can't find out what's wrong!)
Reply With Quote
  #10  
Old 2nd August 2016, 09:05 PM
Quattrodave Quattrodave is offline
Member
 
Join Date: Oct 2015
Posts: 53
Default

So, got close enough to each fuel pump to hear them both running whilst the engine was idling but the rough running still persists.

However, out of curiousity I took a video of the car starting up (from warm), blipping it and then on WOT where again the engine revved only to 4k. Video is linked below - is it me or is that an awful lot of steam and water coming from the exhausts?

This problem started around the time that I got a leak in the passenger (left side) footwell owing to clogged drain plugs in the plenum chamber (now cleared) - could they be related?

http://vid688.photobucket.com/albums...psmmyiobli.mp4
Reply With Quote
Reply

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. The time now is 06:39 AM.


Powered by vBulletin® Version 3.8.0
Copyright ©2000 - 2024, Jelsoft Enterprises Ltd.