Is that right?,
Then why if i've changed all three and after blocking the return they ALL work,i.e hold pressure
That would also be true with other fpr's,not only Webers,such as Bosch units such as those fitted to Jetronic equipped cars,the fpr fitted on those cars work in the same way as the Weber units.
The fuel pump is fitted with a non-return valve that should stop fuel returning to the
fuel tank for a while
The pump prime timing on Weber injected cars will no way be enough to fill the empty lines,rail etc you'd need to turn the ign. switch at least 3/4 times to prime the system.
And i still don't understand how the hell after closing the fuel return line on all 3
fpr's they suddenly all work after various attempts.
The same thing happened on my mates Toyota mr2 turbo that had a Weber fpr temp.
fitted in place of the original unit,on the Toyota the fpr is fitted on the Return circuit
and the Weber unit did the EXACT same thing,at first the unit would not hold pressure for nowt,after crushing the outlet returning to the fuel tank it worked,holding pressure for two days...
Faulty non return valve?,maybe,but the chances of having BOTH cars with faulty fuel non return valves seems a little remote.