2000 Audi A4 #B5 2.5 TDI Quattro - Wont Start (Lift Pump maybe)

Dannos

Registered User
Hi All

First post, so please go easy on me.

My 2.5 TDI suddenly decided it was going to stop working Saturday night (@ 1am) and now wont start. Its got Diesel (even topped it up) & it cranks fine but doesnt fire up. At first i thought it might be the key (as its pretty tatty)/immobilizer connection, but it unlocks the car and turns it (until the battery starts to go flat) so i dont think its that. No warning lights on the dash, the coil and key come on and go as normal. Iv read quite a few similar posts saying its probably the fuel pump, but im a little confused as to which one. Is there 2? 1 in the fuel tank (lift pump) and one at the front (injection pump) (thats a pain in the ar*e to get at)?

Is there anyway i can do a test? Like spraying quick start in the air intake and see if it turns? Should i see if i can hook it up to VCDS? I know it wont hurt, but iv only got a VAGTACHO for my 2001 Ibiza so i need to find/buy one. Please bear in mind that i understand the basics not too technical, so will need idiot instructions. Willing to throw beer and heaps of praise to those that help :) !

Many thanks :)

Dan
 

aragorn

"Stick a V8 in it!"
Staff member
Moderator
VCDS Map User
i think there is no in-tank pump on the VE engines. The main injector pump on the engine sucks the fuel up from the tank.
 

Sturat

Registered User
It may be the crank sensor / engine speed sender (g28) or cam shift position sensor (g40). Both tell the ECU when to inject the fuel, if either of them are faulty it won't fire. Sometimes its an intermittent fault, it'll fire and then die again?
Or it could be something else.
Definitely need to see fault codes to get more of an idea what it is.
I've even seen water in the base of the main ECU housing by the battery full of water which ruined the glow plug relay. This tends to throw loads of weird fault codes up though as there are a few relays in it's base.
Good luck.
 

aragorn

"Stick a V8 in it!"
Staff member
Moderator
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TBH, these engines are renowned for the electronics module on the pump packing up
 

Sturat

Registered User
If i remember correctly you should be able to hear the pump kicking in when you turn in ignition on if it's working.
If the starting is intermittent then it's more likely to be one of the hall sensors imo.
What ever it is I hope you get it sorted quickly, my car's being a pain in the butt.
 

Sturat

Registered User
If you are thinking of taking the fuel pump out make sure your tank is less than half full and mop up the diesel that you spill - it likes to eat the sound proofing under the rear seat (I had a piece of sticky disolved soundproofing stuck to the front of my shoe and walked it into the house)
 

S4_dan

Fire up the Quattro!
VCDS Map User
Where abouts are you? Ideally a scan with vcds will tell you more, rather than just guessing.

But most likely it'll be the injection pump solenoid. Happens too often on the 2.5 engine.
 

Dannos

Registered User
Hey All.

Thanks very much for all your responses. Really appreciate the help. I might go broke trying to distribute the beers at this rate.

So my dad called today and said he had a quick look and it does indeed look like it has a lift pump (in the boot on the drivers side as its an estate). He said it doesnt sound like the pump is engaging. It is however getting voltage.

Hes gonna send me some pics tomorrow so i can give you a better idea.

Im based in London and the car is just outside London in Sevenoaks @ my dads pub. If it is the lift pump, is it better reconditioning it or getting a new/second hand one?

Such a shame as i only got the car the other month too :( !!
 

Sturat

Registered User
I've not had a b6 and never had to change a fuel pump, I've only taken one out of my b7 3.0 tdi cab. to completely drain the fuel tank so I can't help with replacement options, sorry.
Sounds silly but have you undone the small bolt on the side of the fuel filter (get a cloth and wear goggles) to see if there is any fuel pressure when cranking the engine? I think this may tell you if the pump is working?
All my experience is with my two b7's I know they are similar but they aren't exactly he same. Good luck
 

Dannos

Registered User
SO. The saga continues.

Got the pump out and got some pictures too, this is what we have from my Dad........."striped the electric pump
out the yellow thing, that is working ok, so I don't think it is the pump, will
reassemble and test before trying to get it back in the hole.
It might be as simple as a fuse or relay."

Sorry the pics are so small. My dad and technology.

i was reading that a guy call Chris Adams is a bit of a WHIZ with these cars/troubles! Anyone know of him?
 

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Sturat

Registered User
I did all this on my 3.0 tdi b7 when it wasn't working.
Glow plug relay is under ECU, if it's not swimming in water then it's probably ok.
I would definitely replace the crank sensor/engine speed sender and maybe the cam sender it the crank sensor doesn't fix it.
Good luck!
 

aragorn

"Stick a V8 in it!"
Staff member
Moderator
VCDS Map User
Have you scanned it for fault codes?

These engines are renowned for injector pump failure. There is no point throwing sensors at it willy nilly. Its not a 3.0 TDI, its a much more agricultural engine in comparison, and is much simpler.

chris is "adamss24" on here, you could try sending him a PM.
 

adamss24

Registered User
Hi All

First post, so please go easy on me.

My 2.5 TDI suddenly decided it was going to stop working Saturday night (@ 1am) and now wont start. Its got Diesel (even topped it up) & it cranks fine but doesnt fire up. At first i thought it might be the key (as its pretty tatty)/immobilizer connection, but it unlocks the car and turns it (until the battery starts to go flat) so i dont think its that. No warning lights on the dash, the coil and key come on and go as normal. Iv read quite a few similar posts saying its probably the fuel pump, but im a little confused as to which one. Is there 2? 1 in the fuel tank (lift pump) and one at the front (injection pump) (thats a pain in the ar*e to get at)?

Is there anyway i can do a test? Like spraying quick start in the air intake and see if it turns? Should i see if i can hook it up to VCDS? I know it wont hurt, but iv only got a VAGTACHO for my 2001 Ibiza so i need to find/buy one. Please bear in mind that i understand the basics not too technical, so will need idiot instructions. Willing to throw beer and heaps of praise to those that help :) !

Many thanks :)

Dan
Hi, i Would scan for fault codes and as advised above by Kev and a few others- the main fuel pump aka Vp44 is the main culprit ! I suggest you get a code scan and post the definitions on the forum and I could advise you more however I would rebuild the pump and re-time and program ! I wish you did not touch the tank pump, they are very fussy when tampered with.
 

Dannos

Registered User
So, funny thing. After putting it all back together, it still didnt work :( !!

Went and got a can of easy start and after 1 stall and then trying again, the engine is now up and running BAU. Wish id of tried it in the first place like i was going too.

So if anyone ever gets this problem again, EASY START 2 maybe 3 times and that may fix it. Think it was some kind of airlock or suction problem but who knows. Just glad its fixed :) !

Thanks for everyones help :) !
 

Dannos

Registered User
Hi, i Would scan for fault codes and as advised above by Kev and a few others- the main fuel pump aka Vp44 is the main culprit ! I suggest you get a code scan and post the definitions on the forum and I could advise you more however I would rebuild the pump and re-time and program ! I wish you did not touch the tank pump, they are very fussy when tampered with.

SO. Looks like my thanks was a little premature :( !!

Went to start the car yesterday and it displayed exactly the same symptoms as before :( :( ! Got it started again via easy start and it worked fine. Left it for 2 hours. Started fine again. Left it for another 2 hours. Starts fine. Left it for 5 hours and it wont start.

So what im thinking is its got some kind of air lock or the fuel is leaking back towards the tank and draining. Maybe there is some kind of non return valve that isnt working?!

Any ideas on how to test? I had a look and lots of people say could be a leak at either the fuel filter or pump?

I also ran VCDS on it and got the following.

VAG-COM Version: Release 409.1-US


Chassis Type: 8D - Audi A4 B5
Scan: 01,02,03,08,15,17,25,35,45,55,56

-------------------------------------------------------------------------------
Address 01: Engine
Controller: 8D1 907 401
Component: 2.5l/4VTEDC 0000AG D02
Coding: 02014
Shop #: WSC 63251
00010059 130 106CC150_1.V5A496947090
4 Faults Found:
17978 - Engine Start Blocked by Immobilizer
P1570 - 35-10 - - - Intermittent
01441 - Shareware Version. To Decode all DTCs
30-10 - Please Register/Activate - Intermittent
01442 - Shareware Version. To Decode all DTCs
35-00 - Please Register/Activate
00777 - Accelerator Position Sensor (G79)
28-10 - Short to B+ - Intermittent
Readiness: N/A

-------------------------------------------------------------------------------
Address 02: Auto Trans
Controller: 8D0 927 156 DN
Component: AG5 01V 2.5lTDI RdW 3132
Coding: 00001
Shop #: WSC 63251
No fault code found.

-------------------------------------------------------------------------------
Address 03: ABS Brakes
Controller: 8E0 614 111 A
Component: ABS/EDS 5.3 QUATTRO D10
Coding: 0273004284
Shop #: BB 24334
No fault code found.

I cleared the faults and they havent returned!

Any help most greatly appreciated :) !!
 

Dannos

Registered User
I've not had a b6 and never had to change a fuel pump, I've only taken one out of my b7 3.0 tdi cab. to completely drain the fuel tank so I can't help with replacement options, sorry.
Sounds silly but have you undone the small bolt on the side of the fuel filter (get a cloth and wear goggles) to see if there is any fuel pressure when cranking the engine? I think this may tell you if the pump is working?
All my experience is with my two b7's I know they are similar but they aren't exactly he same. Good luck

Hey Stu. Tried your idea of taking the nipple of the fuel filter to see if it squirts and it doesnt :( !!

Thinking i might see if i can take the union (?) valve of the filter and fill the filter up with clean diesel. My reg is X479 so its an early 2000. Is it fitted with a lift+priming pump do you know? Or is it likely to have a VP44 pump that sucks the fuel up? Im only having problems with it sitting for longer than 4 hours, so its almost like a non return valve, but i cant see if the 2.5TDI AKN engine has one :( !!

I can start it via easy start and then she runs fine if i turn her every 2-3 hours.
 

aragorn

"Stick a V8 in it!"
Staff member
Moderator
VCDS Map User
if it has an electric in tank pump, it shouldnt need a priming bulb, as the pump in the tank will push fuel up without issues.

I would jumper the in tank pump (feed 12v into its fuse) and see if its actually pumping fuel.

Check all the fuel pipework for leaks or perished hoses too.
 

Dark of north

Registered User
Hi, i Would scan for fault codes and as advised above by Kev and a few others- the main fuel pump aka Vp44 is the main culprit ! I suggest you get a code scan and post the definitions on the forum and I could advise you more however I would rebuild the pump and re-time and program ! I wish you did not touch the tank pump, they are very fussy when tampered with.
Hi! Has anyone seen adamss24?
 

Sturat

Registered User
Hey Stu. Tried your idea of taking the nipple of the fuel filter to see if it squirts and it doesnt :( !!

Thinking i might see if i can take the union (?) valve of the filter and fill the filter up with clean diesel. My reg is X479 so its an early 2000. Is it fitted with a lift+priming pump do you know? Or is it likely to have a VP44 pump that sucks the fuel up? Im only having problems with it sitting for longer than 4 hours, so its almost like a non return valve, but i cant see if the 2.5TDI AKN engine has one :( !!

I can start it via easy start and then she runs fine if i turn her every 2-3 hours.
As far as I'm aware when the immobilizer kicks in it stops the fuel, so if the immobilizer is stopping fuel then you won't get any fuel pressure and therefore no pressure at the filter. If it were me I think I'd concentrate on the immobilizer fault.
Hope that helps.
Good luck
Stu
 
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