Technical Question - fuel pump?

[Electric Leyland]

Went abroad for a while leaving my Audi 100 (69-76) out to grass. Came back to it this week, hoping for the best with the sun shining as I turned the ignition. Started on the button (fairly new battery) after recently being MOT'ed by top chap DaveRapid up in Royston (highly recommended). Gave it some high revving for a few seconds, all good, but then the revving slowly diminished over about half a minute, gradually decreasing down to a splutter, and then out. Subsequent attempts only lasted seconds. Now nothing. As if it had run out of petrol, but there's 1/4 of a tank in there (as represented by fuel indicator).Looking under the bonnet (not being much of a technical bloke) I think the problem is fuel pump related. Half way up the pipe is a clear plastic ball which is completely empty, and then taking the pipe off and blowing hard into it (towards the tank), my mate could clearly hear the fuel bubbling away in the tank through the (open) petrol cap. No blockages there then. So, I'm guessing the fuel pump is buggered. Presume whacking it with a hammer won't do anything. Could it just be blocked? There's a new one on fleabay now for a fiver (says 71-76 model, looks about right though, I think anyway). I'm going to try and buy that and fit it myself, with a spanner and some allen keys. Is it as simple as it looks? Any advice gratefully received. I've not tackled this sort of thing before. EL

[FredTransit]

Can you run the pump with the pipe off? Is there any petrol coming out?

[mnde]

Okay first thing first before you buy that fuel pump. Disconnect hose running twixt fuel pump and carb. Point away from the engine (e.g. into a bucket). Get your mate to turn engine over. Petrol should spurt strongly in bursts.All those starting attempts could have flooded the engine. Leave 24hrs and try again. Manual or auto choke? Could be blockage in the carb, crap brought through from the tank by hi revving after a long layoff? Been there, done that with my GSA.Check all HT/LT connections are good. Also I had very similar symptoms on my BX a couple of years ago: engine cut out in a car park. Would start again but stopped after diminishing amounts of time, followed by completely unable to start. Stranded, had to be taken home on AA truck. Turned out to be borked coil.Good luck,Mark.

[Electric Leyland]

Good advice, thanks.No petrol seems to come out, no. Already left it for 24 hours, but nothing. Auto choke.Disconnected hose from between pump and carb, pointed away, started engine, turns over no probs, but still nothing. Took pump off, played around with it, seems to work ok, pressure from pipe when you work it in and out. Reattached it all (thinking could have unblocked that) but no. Next, off down to shop to buy new fuel pipe, it could have a split in it that can't be seen, letting in air? By the way there's no leaks under the car at all. So if not, could be blocked carb or knackered coil then.

[Mr_Bo11ox]

It does sound like a dodgy pump, basically if you have disconnected the outlet pipe of the pump and cranked it over and no juice has come out, I think you are pretty close to finding the source of the problem.

 

Incidentally EL, check this thread! Theers a queue of potential shiters wanting to join up right there.

 

http://oldjapanesecar.proboards.com/ind ... hread=1453

 

also I have been contacted by a 'RobTPB' who would like to have his application approved.

[seth]

EL, is it on a steep driveway, nose up? Could you get the car level and try again? If the pump is a bit dodgy it might not be able to pull the fuel up from the tank having drained back while parked but is able once fuel is flowing and the cars driving on flatish roads.

[Electric Leyland]

OK I've stuck a bid on that fuel pump then, only cheap anyhow so be nice to own a new one. I doubt it is the fuel pipe, doesnt appear to have a hole in it anywhere.Have given resident newbie approval man Mr H Sceptre a nudge re the approvals Mr B, hope to sort that out asap. Apart from the usual reason about disallowing obvious spammers, I still can't quite see why so many folks cant get on here, it's weird.It's level on the flat Seth, probably is the pump. Hope to be able to try a new one next week.

[Minimad5]

You said when you blew into the fuel line your mate could hear fuel bubbling in the tank ?Sound like there is fuel in the tank but a very low amountHad the same problem with my dads Audi 200 2.2 turbo, (yes its injection) but he had fuel in the tank an it wouldnt pick it up, popped in a can full an it started straight away.if still no success have you checked the pipe from the tank to the fuel filter ?Maybe rust or corrosion from the tank has block it ust before the filter ???Hope Ya Get It Sorted

[Richard]

Get a length of petrol hose, connect it to the pump input and stick the other end in a petrol can. If that works your fuel pump is probably OK.

[Mr H Sceptre]

Mr BolloxI have now activated those newbies that you informed us of from the Oldjapanesecar forum , with the exception of Frinkmakesyouthink as there is no activation email from him. Any chance you could do me a favour & post a message on the Oldjapanesecar forum & ask finkmakesyouthing to re-register?Thanks a lotHS

[daverapid]

Thanks for the kind words, sorry to hear of your recent troubles!It's most likely a faulty fuel pump, but check the fuel pipe from tank to pump not only for corrosion and blockages, but also for air leaks. If that pipe leaks it will draw air rather than suck fuel....and not necessarily leak fuel until some gets sucked up.Very common fault on RWD Skodas, but same principle applies here.