tveltman

Can anyone (I'm looking at you, Tuomo) tell me what sort of connection hooks the fuel pump to the supply line? I have an '88 S4 and I am interested in replacing the supply line with braided stainless line owing to some possible damage to the other side of the line in the engine bay. I found that the long hard line connects to a short line coming out from under the fuel tank cover, but I didn't have time to drop the cover and investigate. The fitting that I located (essentially behind the rear wheel) is a convex male 16x1.5 fitting (presumably) similar to the one in the engine bay. Am I lucky enough that the fuel pump connects via the standard convex female M16x1.5 fitting (found on the rest of the fuel system, see the stock fuel rails if you aren't sure what I'm talking about), or am I going to have to machine an adapter to -6 AN?

Also, if machining is necessary, what material should I use, given that my hose fittings will be aluminum. I was thinking stainless steel since that would hopefully not rust the connection at the adapter shut, but I am a little worried about an aluminum/stainless steel seal. If I go with aluminum, I may have the same problem at the other side of the adapter (i.e. alu/alu joint seals fine, but alu/steel metric fitting on factory part does not).

TIA

dprantl

It's just a hose clamp that connects the line to the in-tank pump or filter.

Dan
'91 928GT S/C 475hp/460lb.ft

BigAl1

I'm looking at this for my '80 Euro S right now. The output of the pump goes through a fuel filter, then on to a fuel accumulator, then forward to the engine bay. The threaded connection at the output of the fuel filter is M14 x 1.5, and it will need a crush washer to effect a seal. The hose from there is a short hardline that changes to softline under the fuel tank support cradle and continues to the connection you can see in the wheelwell. The hardline leaving the fuel filter output fitting has a metric ball flare on the end (don't know the size or how these are spec'd).
There are M14x1.5 to AN-6 adapters available from Aeroquip, Russels, etc. Also available are the M16x1.5 to AN-6 adapters for other points in the fuel system.

Hope this helps,
Allan

tveltman

Is the '80 fuel system identical to the '88? Also are you sure it's M14x1.5? All of the other fittigs I have run across are M16x1.5. Thanks for the help!

BigAl1

I double checked the outside diameter of the male threads that go into the outlet of the fuel filter are just under 14mm, and the pitch is 1.5mm. I crosschecked the thread pitch vs TPI guage and no-go with 15, 16, 18 TPI, so reassured it is metric pattern. I'm not sure about similarities between years - maybe crosscheck the PNs for the fuel filters? I'll be using a Mahle KL-21.

tveltman

Okay, based on the chart here, that is in fact M14x1.5. The other fittings are all M16x1.5, including the one in the engine bay, so that is a little surprising to me, but good enough. Thanks for the info

smith 928

Contact John Kuhn he does this.