A3 BKD Fuel pressure loss


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Apr 19, 2009
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About a month ago the car had some major work done on it, new cylinder head, cam belt service, con rods, glow plugs and all relevant seals. The car was running fine, then 5 days ago it wouldn't start, it was cranking over, but not 'kicking in' so i thought it was a fuel issue. I had 3/4 tank and the evening before this the car was fine. The first thing I done was checked the fuel filter, it had been changed about a year ago by me. It was pretty black, so I put it back in but decided to get a new one once i'd got the car started. When I refitted the old filter, after 30 seconds or so of cranking, it started to kick in, and idle'd fine. Almost as if air was in the fuel lines, stopping it from starting. So i went and got a new filter, fitted it and for 2 days it was fine. Decided I was going to drive to Paris...bad move. Parked up in Paris for the day, came back in the evening and the same problem car was just cranking but not firing. Breakdown guy came out (French) and the first thing he tried was to whack the fuel tank from underneath while i tried to start the car. Again, after 30 seconds or so it started and was fine again.

He said it was to do with the hot weather, fuel vapour and filling the tank to the max from what i could understand which seemed like a reasonable reason considering how hot it was, and the fact that I had filled the car to the max.

However, once we got home, the next morning it done it again, but it eventually started without needing assistance. So i'm now thinking that the fuel pressure is being lost somewhere.

So far all i've done is have a look at the pipes coming from the fuel filter, but who can recommend where i should start to solving this problem?

Are there any common places that these hoses leak?

Does the above issue sound like air in fuel lines?
First thing to do is get the car scanned for faults. That will give you a clue as to where to start ! (pardon the pun !! ) lol
Oh sorry i forgot to mention...scanned and no faults found.
Im having same issues did you resolve yours? my car a3 bkd makes a rattle / pinking noise when its running rough and judders under load normally 4th,5th and 6th gear as if my wheels are egg shaped.It seems to struggle when boost kicks in around 2,000rpm. I have changed the fuel pump as there was slight oil in the fuel (fuel was pale blue & filter dripped with black oil) but the problem is still there its very odd, seems like fuel starvation as you say. Am getting tired of searching for answers it seems it could be a number of things with these stupid BKD engines! it drove like a dream the day i changed my fuel filter and pump then the very next day a ***** to start, lots of smoke and the pinking noise came back. What makes it harder to eliminate is i had the cam belt/ uprated turbo and a lightened balanced flywheel fitted last week, the pinking noise started before this work but now i am not sure if the cambelt change could be adding to it, one good thing it idles like a dream since fitting the balanced flywheel conversion kit and revs like a petrol car ;) If i get to the bottom of this i will update...
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Not sure if this will help anyone but it seems my fuel pipes were the wrong way round as in the return and send to tandem pump. I have found this diagram here: http://www.viking-heating.co.uk/pics/engine-bay-BKD2.gif and copied the layout, car seems a lot faster and no juddering or flat spot during boost although its still making a pinking sound slightly, this could be until it settles down.. i lost some fuel while changing them over. I really dont know how these pipes got muddled up am guessing when the garage did the cambelt.
The real test will be in the morning when its cooled down to see if it starts ok!
I have changed the fuel pump as there was slight oil in the fuel (fuel was pale blue & filter dripped with black oil) could be leaking injector seals if the fuel is contaminated with oil
by any chance did you see an warming message flash up quick when trying to start? I had something similar but just once the other week
The warning light you see maybe because you are cranking it for too long, mine flashed up oil warning after around 6 seconds of cranking this is normal. I still have the rattling noise sounds like a tractor but goers away for a short time after really hard driving - its not the clutch and seems to be from the middle of the cam area so i am thinking maybe injector issue. Do check your fuel for contamination though, the fuel pump gasket leak after time on these cars and the injector seals wear out all these problems seem to cause the same symptoms also its really easy for a hillbilly garage to muddle up the fuel lines as this was my issue. One way to check its your fuel pressure is to clamp the return line (the one with the fuel temp sensor on it) and run the car to see if it restarts or drives better, when i do this my rattle noise goes away suggesting low pressure or injector problem.