80 quattro - Non-starter

BigT80 · 14-11-08, 09:07 PM

Hi all, Any thoughts on this one?: had to lay my 80q up last year - normally starts pretty well after being laid up, but won't at all now. Was OK when put away in what turns out to be (unfortunately) damp garage

. Seems there is a spark OK, but no smell of fuel or trace of it on plugs. Checked pump relay & it seems to be OK. Could pump have seized? No hurry for response as won't being going back to try again for a few weeks, but any advice meantime appreciated. Thanks.

4v6 · 14-11-08, 10:00 PM

Turn gnition on listen for pump running before the relay cuts it off, then give it a quick crank and listen again.
The pump should run then cut off. If it dosent then id say it was fuses or the relay rather than a seized pump.

spaarky · 15-11-08, 04:04 AM

yep - as 4v6 says, when operating the starter, the fuel pump will only run for a second or so. dunno what carb/injection it has, but it could just need to get fuel pressure back in the FI system, which has leaked away whilst sitting. Are all fuel lines & filters good ? If you underdo the main fuel line into the FI system (if fitted) you should have fuel forced out of the union if there's any pressure there

BigT80 · 23-11-08, 07:07 PM

Quote:

Originally Posted by spaarky

yep - as 4v6 says, when operating the starter, the fuel pump will only run for a second or so. dunno what carb/injection it has, but it could just need to get fuel pressure back in the FI system, which has leaked away whilst sitting. Are all fuel lines & filters good ? If you underdo the main fuel line into the FI system (if fitted) you should have fuel forced out of the union if there's any pressure there

Quote:

Originally Posted by 4v6

Turn gnition on listen for pump running before the relay cuts it off, then give it a quick crank and listen again.
The pump should run then cut off. If it dosent then id say it was fuses or the relay rather than a seized pump.

Thank you gents: I'll try these when I next go to the lock-up & let you know. Appreciate your thoughts. Cheers.

BigT80 · 13-03-09, 05:57 PM

Well back from another try to coax my 80q back into life. No luck, but more thorough check done this time: No priming sound from pump on switching on ignition, but then my Sport does not make much of a noise, but I guessed there should be something; so checked relay & fuses - OK. Decent spark at plugs. Checked earthing of pump under back seat (that one's caught me out before) all OK. So released primary feed from tank to metering head - nowt! Filled line up with fuel & it tried to fire, so think that's where problem is - no fuel being pumped. Ran out of time to directly wire pump to power supply, but would have thought would still try & prime even if u/s. Running fine when put away a year ago. Any other thoughts before I go back and have another go in a couple of weeks? Cheers.

spaarky · 13-03-09, 06:35 PM

certainly sounds like fuel m8, although I had to listen really hard to hear if pump was working, since it's quiet anyway and only runs v briefly during key operation since fuel lines to metering head should normally be under pressure anyway and don't need much push from pump to initially start up. getting fuel to the metering unit would probly be your best best to start with. I had corroded fuel line under heat shield at front of car, stopping lines from pressurising & hence limited fuel to metering head. if it's been laid up for a year, probly all fuel evaporated & any fuel in the tank poss badly degraded now too - apparently does happen & needs new fuel instead of what's in the tank already. also, have you checked that the cold start valve/injector is working ? there is a procedure for doing this in a haynes manual (no, course there's not a manual for quattros, that would make it too easy) - valve should run, if I remember correctly (?) for about 1 to 8 seconds when key is turned - this is effectively the cold start 'choke' for the FI, like the choke/enrichment you'd get on a carb. Problem is, for me anyway, that the duration of the cold start valve fuel spray depends on your engine identifying how cold it is outside, in order to tell the cold start valve how long to run for - this info on temps taken from another 2 engine sensors, but dunno which one and I can't afford to change either, so just takes longer to fire up. I found that changing the plugs made a big difference, so car is easily usable, but didn't solve the problem entirely. you could probly unbolt the cold start valve, put it in a jar & see if any fuel coming out on key operation. as you reckon, tho, I'd check any fuel tank breather isn't blocked (take fuel cap off to be sure), then wire fuel pump direct to batt to hear if working first, then reconnect and see if any fuel getting to metering head & then look at cold start valve if still a problem

vag80 · 13-03-09, 06:35 PM

If pump not running when ignition is first turned on it's a good chance it's the relay

steveb · 13-03-09, 07:04 PM

easy way to test the pump is to put a live feed to it, it should then run all the time if the car then starts you have a faulty relay ora wiring fault (don't leave it like this as in an accident the fuel pump shuts off if the engine stallls it won't if you by pass the relay etc)

BigT80 · 13-03-09, 10:00 PM

Thanks all for these super-fast posts; particularly Spaarky for the very comprehensive response. I'll let you know how it goes on my next visit. Deffo not relay though as swapped it out with my daily runner (80 Sport) whilst there and it worked fine. Temporary live feed to the pump will be my 1st course of action on next visit & see where we go from there. Cheers all!

BigT80 · 09-06-09, 08:46 PM

Quote:

Originally Posted by BigT80

Thanks all for these super-fast posts; particularly Spaarky for the very comprehensive response. I'll let you know how it goes on my next visit. Deffo not relay though as swapped it out with my daily runner (80 Sport) whilst there and it worked fine. Temporary live feed to the pump will be my 1st course of action on next visit & see where we go from there. Cheers all!

Not very interesting, but made another visit to try & start 80q today. Tried direct feed to battery - sparks when I went to connect neg on battery. So having removed pump from rubberised protector - so I could give it a thump I switched on ignition, but with no one there to crank it over; no joy, so opted to replace relay with jump between where pins 30 & 87 (switch part of replay) to give perm live feed (I think!) & then thumped it again. Petrol appeared at metering head where I'd disconnected it, so thought I was in business: so diconnected battery secured all connections & nothing! Pump got very warm tho, & despite further attemps hitting it with rubber mallet: no good. I guess pump moved a bit & then seized again; so replacement pump looks to be answer. Anyone confirm that this is probably why it was getting warm? Cheers in advance. G.

13-03-09, 07:04 PM	#8
steveb Senior Member Classic Audi Club Member Join Date: Jul 2008 Location: West Berkshire Posts: 1,155	easy way to test the pump is to put a live feed to it, it should then run all the time if the car then starts you have a faulty relay ora wiring fault (don't leave it like this as in an accident the fuel pump shuts off if the engine stallls it won't if you by pass the relay etc) __________________ [FONT] '76 Leyland Princess 2200 HLS '79 Scirocco storm '84 WR '89 coupe quattro '01 A2 1.4 TDI SE '14 A3 1.4 TFSI COD [/color][/size][/font]

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14-11-08, 10:00 PM	#2
4v6 Ex Member Classic Audi Club Member Join Date: Dec 2007 Posts: 5,565	Turn gnition on listen for pump running before the relay cuts it off, then give it a quick crank and listen again. The pump should run then cut off. If it dosent then id say it was fuses or the relay rather than a seized pump.

15-11-08, 04:04 AM	#3
spaarky Grown up member Join Date: Oct 2008 Posts: 124	yep - as 4v6 says, when operating the starter, the fuel pump will only run for a second or so. dunno what carb/injection it has, but it could just need to get fuel pressure back in the FI system, which has leaked away whilst sitting. Are all fuel lines & filters good ? If you underdo the main fuel line into the FI system (if fitted) you should have fuel forced out of the union if there's any pressure there

13-03-09, 05:57 PM	#5
BigT80 Grown up member Classic Audi Club Member Join Date: Apr 2008 Posts: 495	Well back from another try to coax my 80q back into life. No luck, but more thorough check done this time: No priming sound from pump on switching on ignition, but then my Sport does not make much of a noise, but I guessed there should be something; so checked relay & fuses - OK. Decent spark at plugs. Checked earthing of pump under back seat (that one's caught me out before) all OK. So released primary feed from tank to metering head - nowt! Filled line up with fuel & it tried to fire, so think that's where problem is - no fuel being pumped. Ran out of time to directly wire pump to power supply, but would have thought would still try & prime even if u/s. Running fine when put away a year ago. Any other thoughts before I go back and have another go in a couple of weeks? Cheers.

13-03-09, 06:35 PM	#6
spaarky Grown up member Join Date: Oct 2008 Posts: 124	certainly sounds like fuel m8, although I had to listen really hard to hear if pump was working, since it's quiet anyway and only runs v briefly during key operation since fuel lines to metering head should normally be under pressure anyway and don't need much push from pump to initially start up. getting fuel to the metering unit would probly be your best best to start with. I had corroded fuel line under heat shield at front of car, stopping lines from pressurising & hence limited fuel to metering head. if it's been laid up for a year, probly all fuel evaporated & any fuel in the tank poss badly degraded now too - apparently does happen & needs new fuel instead of what's in the tank already. also, have you checked that the cold start valve/injector is working ? there is a procedure for doing this in a haynes manual (no, course there's not a manual for quattros, that would make it too easy) - valve should run, if I remember correctly (?) for about 1 to 8 seconds when key is turned - this is effectively the cold start 'choke' for the FI, like the choke/enrichment you'd get on a carb. Problem is, for me anyway, that the duration of the cold start valve fuel spray depends on your engine identifying how cold it is outside, in order to tell the cold start valve how long to run for - this info on temps taken from another 2 engine sensors, but dunno which one and I can't afford to change either, so just takes longer to fire up. I found that changing the plugs made a big difference, so car is easily usable, but didn't solve the problem entirely. you could probly unbolt the cold start valve, put it in a jar & see if any fuel coming out on key operation. as you reckon, tho, I'd check any fuel tank breather isn't blocked (take fuel cap off to be sure), then wire fuel pump direct to batt to hear if working first, then reconnect and see if any fuel getting to metering head & then look at cold start valve if still a problem

13-03-09, 06:35 PM	#7
vag80 Senior Member Classic Audi Club Member Join Date: Oct 2008 Location: Bracknell Posts: 1,967	If pump not running when ignition is first turned on it's a good chance it's the relay

13-03-09, 10:00 PM	#9
BigT80 Grown up member Classic Audi Club Member Join Date: Apr 2008 Posts: 495	Thanks all for these super-fast posts; particularly Spaarky for the very comprehensive response. I'll let you know how it goes on my next visit. Deffo not relay though as swapped it out with my daily runner (80 Sport) whilst there and it worked fine. Temporary live feed to the pump will be my 1st course of action on next visit & see where we go from there. Cheers all!