Strange setup problems

[Ilkka]

Hello,

I bought the HFS-3 system for my Saab NG900 2.0 turbo -96 with the original Trionic 5 engine management system (around 350Hp, 500Nm before the Aquamist). Spent the weekend with the installation and today started to perform final system tests. I instantly ran into strange problems.

Once I turn the ignition key to pre-crank position and wait a few seconds for the system to start, all three lights on the board lit up (constantly). At the same time the pump starts pumping and doesn't stop until I turn the ignition off. I measured the voltage on the injector- wire (soldered to the pin 3 wire coming out of the ECU) during pre-crank, and it was 0.12V. Injectors are Siemens Deka 630cc, 12ohm. The black and white wires are grounded to the chassis ground point near the ECU.

If I start the car, the pump shuts down and the F-IDC led starts to flicker and the two other leds aren't active, just as it should be. Now the injector- measures 14.1V at idle. Injector+ (red wire) and main power (red wire) measure 14.3V (connected to the same pin 60 ignition switched wire coming into the ECU). With the threshold trimmer at the minimum, if I blip the throttle the THRES led lits but nothing comes out of the nozzle. If I put a jumper to the SYS, the nozzle outputs a nice cone.

Below you can find a lot of information on Trionic 5. The ECU pinout can be found on page 125.

Here's how I connectd the HFS-3 to it:
Pin 3 - injector- (green)
Pin 26 - fail safe (cut the wire and used brown and white)
Pin 60 - injector+ (red)

http://trionic.mobixs.eu/Trionic%205.pdf

Any idea how to start debugging the system?

I have access to portable oscilloscope etc, and work daily with electronic instruments and devices.

Thanks!

Ilkka from Finland

A few pictures at different stages of the install.