Dead S2 :( fuel pump?

[BrianSmith_S2]

Hi, my Aby S2 has given me 5 years of reliable joy.... until tonight

Its been running smooth, pulling strong and generally in good shape until earlier tonight i went to start it and it just turned over..... i initially thought my imobiliser fob hadnt engaged and i might have flooded her so i left it 5 mins then turned her over again and she finally started after about 5 seconds.

Incase i had run the battery down i decided to go for a drive.

Everything seemed fine until on full throttle i was only seeing a sluggish boost of 10 psi (normally 19 psi) then it returned to normal then on another full throttle was only seeing 10 psi.... after pulling away from a junction the revs slowly dropped and the engine cut out

It not spins over as if there is no compression. There was now warning noises or any noises when it cut out the cam belt is still there. Im guessing from reading old threads its most probably the 18 year old fuel pump thats failed. I had run it very low on fuel yesterday

I will try and check the pump and relay and fuses tomorrow in daylight, but is it possible to get an Aby fuel pump from German & Swedish? I cant see one listed on their website.

Any help or suggestions well appreciated, especially as its nearly ADI time

Brian

[Polish]

mine spun up as if no compression and it was the key way in the bottom pulley took me a while to find it

[Acidburn]

Easiest way to check if its the fuel pump

put the back seat down so you can see into the boot, and turn on/off the ignition (don't need to start it, just get the lights up) and listen for the fuel pump to prime, you should hear a quick 1-2 second hiss from it. Could also be the relay.

I have vagcom if you want help with that

[BrianSmith_S2]

mine spun up as if no compression and it was the key way in the bottom pulley took me a while to find it

When mines turns over the top pully turns round with the belt, so im guessing the keyway on lower pully is ok.

What damage was done to yours? sounds like a bad thing to happen

[BrianSmith_S2]

Easiest way to check if its the fuel pump

put the back seat down so you can see into the boot, and turn on/off the ignition (don't need to start it, just get the lights up) and listen for the fuel pump to prime, you should hear a quick 1-2 second hiss from it. Could also be the relay.

I have vagcom if you want help with that

Whats your hourly rate as a mechanic

[BrianSmith_S2]

Easiest way to check if its the fuel pump

put the back seat down so you can see into the boot, and turn on/off the ignition (don't need to start it, just get the lights up) and listen for the fuel pump to prime, you should hear a quick 1-2 second hiss from it. Could also be the relay.

I have vagcom if you want help with that

Just been out and tried this out.... i could hear a very faint hum for about 2 seconds.... does that point to the pump being ok?

Maybe its just picked up some crud and is blocked....

[Polish]

my top pulley was spinning (dont ask me why or how) but got away with just putting a new pully on cost about £30 from vag just a bit of an **** to fit do a compression check

[Acidburn]

Just been out and tried this out.... i could hear a very faint hum for about 2 seconds.... does that point to the pump being ok?

Maybe its just picked up some crud and is blocked....

In that case then try pour some water (cupfull should do) down the back of the top pulley (cam position sensor) and see if it starts then, might be good to get some help with this and try it whilst cranking as well. don't need to be a lot of water.

and I don't mind working on others cars I just struggle working on my own

[Polish]

same as me aciburn own my own garage dont mind working on other peoples cars but hate working on mine

[BrianSmith_S2]

In that case then try pour some water (cupfull should do) down the back of the top pulley (cam position sensor) and see if it starts then, might be good to get some help with this and try it whilst cranking as well. don't need to be a lot of water.

and I don't mind working on others cars I just struggle working on my own

I did try this the first time it didnt start, but will try it again. Not sure how this would make it run low boost and cut out tho, i thought the cam position sensor was only used when the engine was being started

[Polish]

when mine broke there was no noise no bangs just cut out then spun as if no compression took me ages to find out what it was changed sensors etc mine is a 3b not an aby i wish i had done a compression check fist off would have saved me a lot time and swearing and cursing

[BrianSmith_S2]

Just purchased a fuel pump from G&S for £42

GSF number 183VG0291 18386F stated as equivalent to 8AO 906 091G

Was told theres no cost to return item if i dont use it, but im guessing it wouldnt do the car harm changing it because the one in there thats probably failed had almost done 170k

[mcandmar]

If it cranks over as normal its probably the fuel pump. They do seem to fail fairly quickly, mine went from miss firing to total failure within 40 miles.

Be careful when removing the high pressure fuel line from the tank cover, its a large banjo bolt that screws into a metal piece embedded in the white plastic cover. As you can see from the picture the bolt had seized up on mine and cracked the plastic while undoing it. From memory it was around ~30 from Audi for a new one.

Trick is to pull the plastic cover up and you can fit a spanner on the bottom side of it to stop it turning and cracking the plastic. Removing the pump is a easy, there are two plastic clips either side you need to push out and the pump will pull straight up out of its holder.

[S2central.net]

I've said this before... let me say it again...

The S2 does NOT prime the fuel pump when you turn the key on.

The little humming noise you hear when you turn the key on is the afterrun water pump - don't believe me - go put your hand on it while a friend turns the key on.

This one smells of camshaft sensor playing up. A 10 pence LED will verify that.

To check the fuel pump is working - the only way to be sure is to have someone crank it (while camshaft sensor unplugged) and crack open the fuel line near the injectors.

Assume you have checked silly stuff like fuses ?

COuld also be a duff relay - number 10 in main panel.

[BrianSmith_S2]

Thanks Paul

I checked all fuses ..... all ok

Popped open the fuel relay and closed the contacts manually and i could hear a gush of fuel in the lines... turned on ignition yet it wouldnt fire up.

Then i removed & inspected the spark plugs ..they were all dry, not a sniff of fuel

Cracked open both inlet and return fuel lines just under and behind ISV and operated relay and there was a fountain of fuel.... in fact when i released the relay the fuel carried on spraying... panic stations i suddenly realised the relay had latched closed somehow so i opened it and the fountain stopped So Fuel pumps ok then

Does the cam sensor control both ignition and fueling on startup? And even if it does my problem wasnt just starting the car, but it went low on boost and cut out... is this a symptom of the sensor as well? I guess i better invest 10p tomorrow and by myself an LED and read up on blink codes.... unless theres a friendly forum member near to me in the Surrey/Hampshire area with vagcom

Brian