Audi 80 cc - I know its not a MK1 but...

[qsilverza]

Hi,

As per above I have an audi 80 '86 model K-jet.

I couldn't get her to start and worked out that it was the fuel pump. So in the process of getting the fuel pump out which was well stuck I snapped a fuel line.

After getting another one of these made up, I hooked it up with another fuel pump that was working and the new fuel line was leaking but fuel was being pumped by the new fuel pump.

So I took the line back, got it remade and than slotted it back in, this time the fuel line didn't leak but than once again after checking a few things , this fuel pump has gone as well !! (I checked the fuel pumps by hooking them up directly to battery and just electronic Bzzt noise on connection but no whirring as per normal)

A respected audi mechanic friend of mine tends to think there is a blockage in the pipe causing the fuel pump's to fry, I thought initially it was an overvoltage of some sort but I checked and it looked ok.

So any idea's before I slot another fuel pump in ? My guess is that it's after the fuel accumalator and filter and in the K-jet system as the new pipe was leaking after the filter and near the K-jet braided line.


Is there anyway to be sure Maybe a stronger pump that won't blow or blowing compressed air through the lines ? or is the problem lying with an overvoltage or possibly even an undervoltage ?

UPDATE 23/02/09

Pulled fuel tank some rust so cleaning with industrial stuff !

PICS added* and pics to come of tank and rust.

[roccodingo]

fuel pump

If you are running the fuel pump dry ( disconnected from the fuel tank) you are most likely destroying the pump. The K jet fuel pump requires fuel in the pump for cooling of the components.

loosen the fuel line after the fuel pump and see if fuel will leak out the joint when the pump is run. re tighten and move to the next join or component, ( accumilator, then fuel filter , metering head etc) to find where there is no fuel leaking when the pump is running. then the restriction is between ther eand the last known leaking joint.

Have you changed the fuel filter ??? do you have a manual for info ??

Has the tank got rust in it which also kills the pump quickly ??

HTH

cheers.
Grant.

[qsilverza]

Not running the fuel pump dry, only to check, once it had gone.

I will clean the fuel tank to be sure and will replace filter. I guess i was a bit eager to get it started !!! How do I clean the tank ? What do you suggest ?

I don't have a manual, but another something to mention, I have another what looks to be filter. So my fuel system goes,

Fuel tank
Fuel filter small (I think)
Fuel pump
Fuel accumalator
Fuel filter (Big)
Main fuel line
K-jet Braided fuel line
K-jet

As, I said when the fuel line was not pressurised properly it didn't die. But that could be because, I tried it with that new line so it could be the fuel tank isn't clean and gunked up the pump.

If you are running the fuel pump dry ( disconnected from the fuel tank) you are most likely destroying the pump. The K jet fuel pump requires fuel in the pump for cooling of the components.

loosen the fuel line after the fuel pump and see if fuel will leak out the joint when the pump is run. re tighten and move to the next join or component, ( accumilator, then fuel filter , metering head etc) to find where there is no fuel leaking when the pump is running. then the restriction is between ther eand the last known leaking joint.

Have you changed the fuel filter ??? do you have a manual for info ??

Has the tank got rust in it which also kills the pump quickly ??

HTH

cheers.
Grant.

[roccodingo]

Yeah, just checked the layout on ETKA.

you could try using an extending magnetic pick up tool into the tank neck and see if you pick up rust and scale.., or remove the tank and clean it out ( flush)

when thats verified as ok, make sure you get a good flow of fuel out of the hose that connects to the in side of the fuel pump. the primary filter could be blocked, unsure if Audi 80 tanks use the same screen set up in tank as the VW's.

If the car has been sitting for a considerable period of time the fuel lines could be severely gummed up from old fuel. One of my rocco's would only drip a drop of fuel out the tank when the outlet hose was removed, solution was to replace the tank.

[Jmac]

Yeah a blocked filter will cause a rise in current draw at the pump. You also have a lift pump in the tank that has a gauze. This could be blocked as well. You already know running a roller cell pump will stuff it. WIth the 2nd pump on did it actually run before it died?????? Reason i ask is that there is something fair wrong with wiring if it died straight away, if the pump was a known good pump
CHeers
Jmac

[Golf Loon]

You could also reverse the electrical connection on the pump and see if that makes it unblock and shift the blockage.

[qsilverza]

Rocco, will remove and flush tank and check gauze and secondary filter in tank and the other filter. Flush it with clean fuel I guess ?

There was a good flow out of the tank through the small filter, I know because, I drained the tank before, I ran the car and I got enough fuel on me to make me the flame man !!! Not something I want to do again. lol. But it was old fuel so maybe the new fuel has cleaned the gunk off and blocked the filters.

Jmac, the second pump did run as I said, but it was with the new fuel line that wasn't pressurised properly.

Golfloon, I have tried reversing the current, but not while in the system. That might be something to try !!

Could the K-jet system be at fault here, or is the problem lying in the fuel system ? In any case, I will remove the tank and clean plus try and check and clean as many things as possible.

Anyone know where I can get a manual for these ? I have vag repair software but it doesn't include the 80. Maybe I could just use a something from a VW engine.

[Peter Jones]

This is handy.

http://www.diagnostic-assistance.co.uk/mech_inj.htm

Pete

[qsilverza]

That's very cool !!

This is handy.

http://www.diagnostic-assistance.co.uk/mech_inj.htm

Pete

[XXX-1.8T]

i want to see more pics of the car!

[qsilverza]

The 80 ? I have some up on somwehere, I will find the link and post for you

[qsilverza]

Ok, pulled the tank and checked. Looks like rust and like a brownish black goop, so going to use some industrial cleaner and try and empty it out.

I may use muriatic acid as per some guides but I will start off slow before I do the full blown process and see how clean she comes.

I'll bet this is why my pumps keep going !!!

In any case, at least I have some movement !! I can't tell you how good a feeling it will be if I ever get this thing running !

Is it possible to disassemble a fuel pump ?

*ADDED pics at beginning of thread.