AFN No start?

[andy10v]

Looking for help with B5 A4 1.9tdi Quattro AFN 110bhp.

Cranks, but does not start.
Caught for 1/2 second a couple of times.

Not like immobilizer cut.

No fuel at injectors when cranking

No glow plug light when ignition switched on (Is there an equivalent to the VW 109 relay that powers most of the engine electronics?)

No codes.

I changed the pump head seal, IQ seal, top cover seal about a month ago, IQ set with vagcom. (Was leaking previously) Car ran fine for the last month. A couple of days ago the car split a rad hose (where the diesel had leaked on).

I replaced the rad hose (forgot to disconnect the battery, and touched the back of the alternator with something metal and got a spark )

Drove the car straight after replacing the rad hose, worked perfectly, ran up to temp. Had 1/4 tank of fuel so filled to the neck and drove the car home.

Tried to start the car the next day, and it spins but does not crank.

I cant see any obvious fuel leaks
Checked fuses
No codes in vagcom
Tried another ECU, no different

Any suggestions/advice appreciated

[ManiacuV6]

IF you tried another ECU did you made the adaptation with immobiliser box ?

[Acidburn]

on my one it had a lifter pump in the tank which could be playing up and not supplying enough fuel. Could check and see if thats pumping?

I "may" still have the one from my conversion as I never did fit it but i'd have to check and see, I got rid of a lot of the stuff from that.

[diesel des]

Did you fill it with diesel...

Sent from my GT-N7105 using Tapatalk 2

[andy10v]

IF you tried another ECU did you made the adaptation with immobiliser box ?

Nope, did not bother, but it behaved exactly the same. It normally starts and runs for a couple of seconds on a immobilized ecu.

[andy10v]

on my one it had a lifter pump in the tank which could be playing up and not supplying enough fuel. Could check and see if thats pumping?

I "may" still have the one from my conversion as I never did fit it but i'd have to check and see, I got rid of a lot of the stuff from that.

I understood the AFN did not have a lift pump, it was purely suction from the main pump, and therefore any leak will ingest air.

[andy10v]

Did you fill it with diesel...

Sent from my GT-N7105 using Tapatalk 2

Nope, deffo the black pump.

I did also check my tank, it has diesel in it.

[andy10v]

So it runs.

I drained the fuel filter, checked the fuel stop solenoid (removed and bench tested, plunger operating freely). Put it all back together in disgust as I had not found anything wrong. My dad wanted to prime/bleed it to see what happened, and after bleeding the air out the injectors it runs

So maybe;
fuel line disturbed when I changed the coolant hose enough to create and air lock
water in the filter
bit of something jammed the cut off plunger
some random thing disturbed in the tank
?

I am inclined to get a new fuel filter and all new rubber fuel hoses.

[irish rwd]

Had this problem on a 97 AFN A4, cranked over and over, might catch the odd time and cut out again. I deimmobilised 2 ecu with no luck, turned out it was down to complete wear in the injector pump. (280k). Try installing a manual lift pump like the ones seen on the old pug or rover diesels, and pump the diesel into the injector pump while someone is cranking it over, it should fire into life. I installed a non return valve then in the fuel line to stop the diesel returning. Worked a treat

[irish rwd]

Sorry I was in the middle of writing when you commented just before me ! Glad you got sorted

[5cylinderman]

The easiest way to ensure the pump is primed with fuel is to get a rubber bulb hand primer off a 1.9 D Berlingo or 306 D. IIRC Nissan fit them to Primastar vans too.
Also, crack two of the injector connections while cranking at full throttle. It helps the pump purge any air.
Check the multiplug connectors in the pump loom in the engine bay as you may have disturbed something.
The plastic T piece in the top of the fuel filter can sometimes leak air and prevent proper bleeding. The O ring can get trapped/twisted and cause fuel drain back to the tank overnight.

[andy10v]

Thank you very much for the info/ideas guys

I like the manual pump idea.

Went to start it this morning and it spun a few times before it caught. Switched it off and it started straight up.

Ordered a fuel filter and picked up some fuel line from audi today so will make sure that is all ok.

[martinws]

I might have a few manual bulb pumps at home that I used when had bike carbs on my old coupe. I got the from a Citroen Xxsara I think.