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When parked on an incline or after going up ramps etc the car won't start :(
Cracking open the injectors and bleeding it fixes the problem.. I've tried replacing the fuel filter but that hasn't fixed it :(
Any ideas? Can't see any leaks anywhere and fuel economy seems as average as ever..
Have same issue & still not found root cause. The problem appears to be pressure build up in the tank. If I leave my fuel cap loose the problem disappears.
There should be no need to crack the injectors. If mine stops after parking on incline I find the cap has self tightened so opening it and cranking gets it restarted.
really appreciate the reply.. will try that next time!!
I'll ask my audi-tech mate and see if it could be something to do with the tank-gas evap system thingy..
Check your lift pump in the fuel tank. Mine stopped working but car still ran but lots of air in fuel line ( you can see throughr the clear pipe nr. the VE pump.) £600 from *********** - now OK.
so whats the easiest way to check my lifter pump?
Rocket science. Can you hear it running in the tank filler for the first few seconds. ???
https://www.vwaudiforum.co.uk/forum/s...ad.php?t=13380
Regards
Peter
Mine was running but it did not deliver any fuel.
You can disconnect the input to the fuel filter and crank the engine, diesel should come out.
Ask him to have a look at the archive technical solutions if he works for audi main dealer,there is some info on this but if i remember there was never a fix but the symptom was accepted(fuel pick ups at the front of the tank hence fuel movement allows air to be drawn instead of fuel when parked on an incline)always leave more than than a quarter full.
well it has been ok and now started playing up :(
tried leaving the filler cap open but no joy.. booked into a good independant dealer on tuesday so fingers crossed..
I don't understand though how a failing pump would allow air into the system, especially if it's a submerged type..
Attachment 1000On vehicles with four-wheel drive the fuel tank is divided into a left and a right chamber.
t A so-called suction-jet pump -item 6- (left-side) is used for delivering the fuel from the left fuel tank chamber to the baffle housing of the fuel delivery unit -item 4- on the right.
t A second suction-jet pump -item 1- is located in the right fuel tank chamber and serves to improve the fuel delivery in the right fuel tank chamber to the baffle housing of the fuel delivery unit.
t The suction-jet pumps operate according to the principle of fluid entrainment: a stream of fuel delivered from the fuel pump fitted exclusively for this purpose -item 7- is passed through a nozzle in the suction-jet pumps -item 1- and -item 6-, and is thus accelerated. The accelerated stream of fuel draws off the surrounding fuel and delivers it to the baffle housing of the fuel delivery unit. The right suction-jet pump -item 1- delivers the fuel directly into the baffle housing, the left suction-jet pump -item 6- delivers the fuel via a separate pipe -item 5-.
t The fuel is distributed from the fuel pump -item 7- to the two suction-jet pumps via the connecting piece -item 8-. At the same time, the connecting piece restricts the pressure in the pipes to the suction jet pumps. Excess fuel is delivered via the Y-connector -item 2- and directly via another pipe -item 3- to the baffle housing.
t Unlike the system employed for petrol engines, the fuel supply and fuel return pipes to/from the engine are not required for the delivery of fuel to the suction jet pumps. As on vehicles with 6-cylinder engine and front-wheel drive, the injection pump is sufficient to draw off fuel from the baffle housing in the right fuel tank chamber
sorry iam thinking about the complaints when the vehicles were parked on a incline and wouldnt start,there was air being drawn through and eventually fuel.
Checking suction pump
Procedure
l Battery voltage at least 12.5 V
l Fuse in fuse holder -S228- (position 28) OK.
l Ignition off.
l Fuel tank max. 1/4 full. Drain the tank if necessary.
– Open fuse box cover on left-hand side of instrument panel.
– Take out fuse in fuse holder -S228- (position 28, left row, 5th large fuse from the top).
– Connect remote control -V.A.G 1348/3A- for V.A.G 1348 with adapter cable -V.A.G 1348/3-2- to right-hand terminal -arrow- on socket of fuse -S228-.
– Connect crocodile clamp to positive (+) terminal of battery.
– Remove rear seat bench →
– Detach cover for flange (left-side) -arrows-.
– Unplug electrical connector -arrow- at flange (left side of vehicle).
Caution
The fuel tank must not be more than 1/4 full when removing the suction-jet pump. Otherwise a large amount of fuel will escape.
– Unscrew locking ring using wrench -
– Carefully pull fuel gauge sender 2 -G169- and seal just slightly out of opening in fuel tank.
– Use torch to check content of tank (through gap between flange and fuel tank opening).
– Make sure the left fuel tank chamber contains at least 2 litres of fuel. Use hose to fill tank with fuel as required.
– Press remote control button.
l The suction jet pump should draw off a noticeable amount of fuel from the left fuel tank chamber.
If the fuel level does not drop:
– Check hoses, suction-jet pump, connecting piece and fuel pump.
cool i'll have a play.. wonder if can improvise the tool needed to remove the pump...
just bridge it out for short time,as i say sorry for misleading you before i am covering to meny forums and confusing myself(not reading the posts fully)
so best bet is:
1/4 tank fuel
wait till car doesn't start
bridge connections
see if it starts..
if it does then i take it a relay or sensor is duff?
If it doesn't what are my choices then?
thanks for any help!
pretty much,you could check supply voltage and take it from there.
The pump is fine - if it wasn't you would never get the tank down to 1/4 full.
I think the problem is with one way valves to/from the suction jet pumps. On a pump with issues these don't seem to close/operate in the same sequence when compared to a new one.
Unfortunately they are not replaceable parts so a new fuel delivery unit must be fitted to get a full fix.
The pump is not a lift pump. It's only function is to keep the fuel delivery reservoir full so the injector pump can draw the fuel off. However from 2002 all models (front wheel drive & Quattro) were fitted with a pump. In addition the valve arrangements were changed on the pump were altered to allow some pumped fuel to flow forward to the filter. It seems this was to improve fuel cooling for use in warmer climates. Unlikely performance will be affected in northern Europe. In addition the tank reservoir cannot be emptied by the engine as the low fuel sensor will shut the engine down. The injector pump also has a lack of fuel sensor that shuts the engine down before air reaches the timing piston. The only problem with not changing the pump is the nuisance factor. A cheap fix would be to insert a non return valve between the supply and filter or injector pump. The easiest way to get one is by fitting a hand prime fuel pump - a black bulb thing that you squeeze.
In my case the valves are just a little weak thus if I leave the tank completely vented and not let it pressurise I don't experience trouble - but will probably get worse.
well just got a call from the audi independant near here who have replaced the fuel return lines and the one way valves so we'll see if that fixes it..
if not i'll just whack a non return valve inline as you suggested.. do you know offhand what bore the pipe is to the fuel filter or to the pump?
To be clear the valves I mention are in the tank and require the fuel delivery unit to be removed. I suspect your shop may be refering to the fuel return regulation valve on the filter.
6mm pipe.
Ok the return pipes have been replaced, only time will see if that fixes it..
I've ordered a one way valve hand primer just in case. Can you tell me though what the 4 pipes are that connect to the fuel filter?
There is one each side of the t-piece and two which connect directly to the fuel filter. I can understand if there was only two! Which one would i connect the one way valve too?
Btw I really appreciate your time helping with this thread! cheers!
Mark
The left rear pipe is the fuel inlet to the filter & the right rear is the outlet to the injector pump.
The front right is the fuel return from the injector pump & injectors. The front left is the fuel return to the tank. The 'T' piece is the fuel preheat regulation valve
damn thought i'd fixed it by changing the injector return pipes, but it's doing it again...
which pipe on the fuel filter would you advise fitting the non return valve/primer onto?
I assume the best bet is the top left ie the feed from the tank to the filter.. if it still fails after that then i guess i've isolated the problem to be the pump or connectors around the engine bay?
right lets see if this bloody works.. getting bored now of having to park a certain way on slopes.. getting embarrasing..
http://pix.m6rk.com/2.5tdi.jpg
you no you need the fuel tank pump to increase the delivary pressure/rate to fully resolve this issue,but i like this contraption
well it didn't work :(
any other ideas!
Do you mean the contraption
yeah the contraption.. the bladder gets sucked into itself when parked overnight which i assume is the vacuum from the tank pulling it back against it's own one way valve.. but with this occuring sometimes it starts and othertimes not still..
i can't figure out where the air leak is... i've reached the limit of my capabilities :(
FYI for those who have been following this thread, or will google it in the future.. my problems have finally been fixed!
In the end I put a pressure gauge from the lift pump and found it was struggling. Replaced the lift pump (with help from friendly audi man with the right tools to undo the lock rings etc) and it's solved the issue. It's no longer sucking air, I've got the old lift pump to play with so can only assume the pump was failing and sucking in air from somewhere.. still at a loss to explain how though as the pump is sealed.. unless there is a one way valve somewhere in the pump too?
but it's back on the road at last hurrah!
ARGH!!!
spoke too soon..
anyone got any other ideas??
so far:
replaced leak off pipes
replaced lift pump
electric fuelpump in the tank and the temp valve on the fuel filter.Try clamping the return pipe off overnight and see if it starts better.
when i said lift pump.. perhaps i was using the wrong phrase..
I've replaced the pump on the passenger seat behind the driver with the lift motor in.. the tank drains to under 1/4 of a tank so the other pump must be ok i assume..
Or maybe not.Try priming the pump before starting by bridging the supply fuse,this will give some indication to the fuel delivary rate.Also as i said try to stop the fuel returning overnight by clamping the pipes then start and remove the clamps.Dont do both at the same time though.
excuse my ignorance but how do i bridge the supply fuse? I'll try clamping the return line tonight..
bridge fuse 228 20 amp with a fuse wireand this will supply the pump
i've been away in the states on work until now, on my return i've found by priming the car (turning ignition on and off) and then pumping the acclerator i can get it to start...
clamping the return seems to help a bit, but it still doesn't start as well as it should..
I've bridged the supply fuse and get a healthy amount of fuel pumped through too.
whats the likelyhood of it being the Injection pump causing the leak? I've got it booked in at a diesel specalist who can also recon the pump if required, but i don't want to get ripped off if i can help it.
just to add to this for those who are interested...
even though the car ran ok once started, it has been diagnosed as an issue with the vp44 injection pump.
I put one way valves either side of the IP, at the diesel specialists they said that the IP was weak. even though the car pulled well. Pressure tested the entire system and no leaks were found right up to the IP.
£900+vat for a recon pump so we'll see it that solves it on friday!
ok finally fixed..
for anyone interested the advance piston was well worn in the bore.. so the vp44 needed a complete overhall including a new housing insert... would definately recommend m&c diesels in colchester and PB asher in southampton for the vp44 overhaul..
I appear to have warped my discs in the meantime, so thats the next job :( argh...