Fuel to engine problem Audi 80 Sport 84'
 

Hello,
I am experiencing problems with my Audi 80 sport (1984)
Recently my car has been stalling due to what seems to be a lack of fuel getting to the engine. I have tried changing the fuel filter and clearing out some of the crap that's in the plastic reservoir near the electronic fuel pump. (sorry about my lack of knowledge coming out in my writing)

Basically what happens is: I turn the ignition over and can hear the pump working and the relay ticks twice indicating it seems to be working. I will then be driving along and the fuel pump starts making a loud struggling noise then i start to feel the engine stalling with lack of fuel.

Any ideas to answer my probably dumb ass question?

Thanks,
Mark

get a new fuel pump....................:D

Does the car run normally for the rest of the time? How long before the symptoms occur after starting?

It could be you are pulling bits of debris from the tank. Have you checked the filters again?

Fuel flow test. Fuel injection pumps for K-jet (I'm going to feel really daft if it isn't K-jet, or even injection) should deliver about 4ltr/min, as measured on the return to the fuel tank. And about 5bar pressure.

There's been some discussion over on the other channel- http://www.quattroforum.com/forum/wr...ving-fuel.html

and here, for the ur, but the basics can be applied to all similar era machinery
http://www.isham-research.co.uk/quattro/fuel_pump.html

a new fuel pump would be my first port of call.

Sounds like it could be on the way out. I had similar symptoms with my old coupe a few years go.
Word of advice, Audi can get them but go to GSF as they were less than half the price of what the main dealer quoted and had them in stock.

Does it have 2 filters,like mine?Small plastic(gravity)one,then a larger metal canister one nearer pump?

try running it with the fuel cap off..............?? blocked tank vent

Yeah it has the 2 filters. Ill try having the cap off for a while. I just didnt want to go spending money on pumps if it is still working. (student budget) :o

What happens is ill be driving for about 500 yards then it will stall but fuel pump seems to be struggling. Perhaps there is still shit in the tank. :idea: It then starts fine, so im driving along and having to coast for a bit while i turn the key to pump some more fuel in. It then seems to last as long as that small amount of fuel lasts. And yes it is K-Jet and my 'car expert mate' knows sod all about really.

Ta for replies kind people

how noisy is the fuel pump???????

On cold start its fairly constant, when warm its quieter. With this new problem the noise gets louder as it is about to stall. When i changed the fuel filter last week it was pumping fine but sounds like its struggling.

If the noise gets louder before it's about to stall, it could be a fuel blockage before the pump.


Sounds like something is restricting the fuel flow which is causing the pump to do that.

just process of elimination.......we'll get there in the end.

are you damn sure its starvation and not flooding...? checked the plugs..??

check the earth for the pump,chances are it will be corroded and giving an intermittant connection,you can test this by linking in a temporary earth on the negative terminal on pump then driving car to see if symptoms persist,while you are there make sure both positive and negative terminals on pump are secure...if this dosent sort it then change the relay(easy and cheap)also check connections on plug to relay and give them a blast of WD,relays can break down over time as they only contain a wire coil and a set of duel points similar to ignition points........if neither of these virtually free repairs cure it then it will be the pump cos theres nothing left....its doubtful to be tank debris but even if it is then it renders the pump U/S

I got the impression that this was happening infrequently. But with it happening so quickly, I'm inclined to think that the fuel pump is a likely culprit.

But. I'm not a fan of replacing things until some work has been done to identify exactly whats happening.

as mentioned earlier

-4ltr/min roughly, checked at the return line.
-5bar pressure minimum, with the system connected normally
-5-8 amps running current, and the pump really does need 12v to work well (there is a relay mod which has been carried out on ur's a lot)
-Fuel pump relays can be at issue, occasionally. Bridging the relay contacts so the pump runs continuously is worth a go. ONLY for test purposes, to identify the problem. If that works, then a new relay. Don't be tempted to run that permanently.
-check the filters again, see if they are full of crap, again. How much did you remove last time?

Yeah, cheers coxy. Any tips on trying to check/clear blockage from tank? :hmmm:

See because i was wondering if all the audi's of that era had 2 fuel pumps. Wasn't sure if the previous owner had put an electric one on and there was some kind of fight between the electronic and the mechanical pump. But the answer is probably bits of rust in the tank. :wall:

tank out job on mine.............t'was fun....!

..where is the pump...is it 'in tank' ....''wet pump''...??

Cheers, I have lifted rear seat to check the earth which seemed fine. (took it off and scratched at it for good measure)
As for the relay, it sounds normal to me as if its doing its job. Do you know why the relay clicks twice if the ignition is turned half (engine not on) But on full ignition it only 'clicks' once. Is this normal? It basically gives two bursts of fuel on half key turn but only one on full ignition.

Not a wet pump, unless there another one of the bastards that i dont know about. Its all just a bit strange. I changed the fuel filter and petrol was pissing free from the tank non stop so then makes me wonder what else it could be. Its going to be a trail and error situation i think. Ill start with the cheap options like taking cap off, then check line pressure; last option taking the f'ing tank out :(

Think a fuel pump will have to be in order perhaps.

It needn't be. I know it's your daily machine, but some time and considered action will pay dividends.

Yeah I welcome myself to classic car motoring :tup: I knew it wasn't going to be plain sailing - wheres the fun in that ay? :moon: But thanks for all the help! I'm no mechanic but always up for learning, the hard way perhaps. :ihih:

when the pump is first powered up(2nd turn on key i expect)it will fuel up to pressure then turn off until the pressure drops,ie it starts,when you switch to ignition the pump is already up to pressure so wont need any more than one pump,i expect if you sit in car with ign on but engine not running youll find that the pump clicks every 30 seconds or so to maintain fuel pressure......change the relay,or just temporarily swop it with a headlight one to test,make sure the relay you use has the same amount of terminals and make sure it aint an indicator or hazard light relay.......you can bridge the terminals to test as the guy said before but im geussing that your probrably not proficient in electrics so your better off just swopping relays as you cant cause any damage doing this ok

take a visit to the scrapyard or buy a 2nd hand one off here,im sure someone will have one,you should get one for under 20 quid 2nd hand....if the scrap yard aint got an audi pump then look for anything older ford,granny,scorpio,sierra etc etc,with fuel injection,the pump is located on the outside front of the tank underneath,these pumps will power any make of fuel injection and are simple and reliable,ive used them on all sorts from jags to jap stuff......there is a very slight chance that the pick-up inside the tank has worked loose,simple way to test this is to fill the tank right up,if problem stops,then get yer spanners out cos your dropping the tank......but,this is doubtful and my geuss is that if you follow the steps ive listed then youll cure your problem long before you need to spend 60 quid on fuel!