Ok people sorry for this dumb question. Which injecotrs are 'secondaries' and 'primaries'? The ones that are actually in the block or the ones that sit on the manifold? About to install my 1600s an 720s and need to make sure I got them in the right place lol.

 

Primary injectors are the ones that are "in the block" and secondary injectors are the ones that go into the lower intake manifold.

 

And to follow up with another question. Can anyone point me in the direction of getting 2 new o-rings for the injector at the top, where the fuel rail goes. I have 8 used injectors, if the o-rings look to be alright could I re-use them or is this a bad idea? They are going on 720cc injectors, and I got a wally 255.

 

You could use the old ones as long as you don't break them.

Once the injectors are installed, and prior to reinstalling the upper intake manifold, what your supposed to do is jumper the yellow two socket fuel pump check connector and then turn the key to ON. The fuel rails should pressurize and you leave the key to ON for several minutes and look for leaks around the fuel injectors.

That's why the Fuel Pump Check Connector exists in life.

And or you could buy new o'rings from McMaster Carr as shown in the jpg below. I doubt you'll be able to beat their price for 25 of 'em. They deliver in three work days if you order before noon. Usually.

 

i have a question sorry for thread jacking..

have a s4 t2 i have setup n/a using stock ecu etc etc if i put n/a 460cc injectors instead of the 550cc would the ecu run them fine or would it try run them like 550 and not operate correctly?

 

It'll run lean. The ECU expects 550's are in the engine and is programmed for 550's. It can't tell one injector from another. It depends on You to put the right item in the fuel rail.

 

Thanks HAILERS its appreciated