What can cause no negative injector pulse on a S4 T2?? Any suggestions would be much appreciated!

 

How do you know the ECU is'nt pulsing a ground to the primary injectors?

One way to almost confirm there is a pulse by the ECU, is to crank the engine over as to start the car, and watch the tach needle. It should make very small bumps up/down as the engine is rotated. That means the trail coil is being pulsed by the ECU and I"ve found in the past that it also means the primary injectors are gettng pulsed by the ECU (used LED light tapped into the primary injector wiring at the ECU's small plug).

I assumed you have spark since you didn't mention the lack of spark. If you have spark, then the CAS wiring to the ECU is good and not the problem.

You did not mention if you have gone to the small plug on the ECU and checked for POWER on the light green wires when the key is put to ON. Should be there. IF not, then find out why not. A reason for NOT is having the solenoid resistor disconnected on early series four cars.

The ENGINE fuse and both EGI fuse have to be good to have spark/fuel on a series four car.