Injector wiring
 

I have a `90 Vert Turbo. After blowing some seals, I had it rebuilt by Banzai Racing in Ind. I had GSL-SE injectors installed for secondaries. Where should I look for the resister change for replacing them with stock inj.? Bad gas mileage and only getting about 5# of boost with stock S5 turbo, engine has street port and 3" exhaust but I think the cat. is fouled by too much fuel and not enough boost.

The injector has two terminals. W/the multimeter set to resistance, one meter terminal is placed on one of the two injector terminals and the other meter terminal applied to the lone injector terminal. High resistance injectors should read about 10 to 12 ohms or so.

Injector wiring
 

OK, I understand there will be a difference. The GSL-SE inj. have a different impedence, I want to put the original inj. in, How??

The FSM will guide you on how to remove the current injectors. The secondary injectors are rather easy to access while the primaries are not, thus you'll have to remove the upper manifold in the process.

So there are no changes to the wiring or computer? I have the inj. and a spare computer, so if I need changes , well, that`s what I`m asking...

I appreciate that you`re taking time to answer, but I`m trying to figure if there`s a wiring change or something to make the GSL-SE inj. work. They are coming out and stock inj. are going in, then, a cat change and 02 sensor...

The SE inj. are in as secondaries,,,

Your 90 S5 requires high impedance injectors so if that's what you want to to install as a replacement to the low impedance injectors then it is a simple swap. If your GSL injectors are low impedance and the car was set up to work off of low impedance injectors then there would have been a change made so the low impedance injectors would have worked and that would be either resistors were placed inline along one of the wires to each injector or a resistor box (found on early S4's) was wired in to do the same thing. If you have neither then it is a simple remove the old and replace with the new.

In looking back at your original post if you had a shop install low impedance injectors on a high impedance system then there would be a change made as illustrated above but this takes into account that the injectors were indeed low impedance and they knew what they were doing. If they installed low impedance on your S5 and made the modification necessary then there would be an inline resistor on both of the secondary injector wiring (only one resistor per injector and there are two wires to each injector so one of them would have the resistor). And this resistor would need to be removed.

Thanks! That`s what I`ve been asking...

The resistors are installed at the ECU where there is only one wire to each injector. You will need to solder on S5 injector connectors.