AC S.A. all rights reserved. Under penalty of law and/or liability claims it is forbidden to copy, publish, distribute, make available and/or use in any way all or any part of information contained
within this document, in particular photographs, drawings, illustrations, trademarks, etc
20
1.11. Selection of pressure regulator
Install the controller according to the layout show in Fig. 1 to Fig. 6. In a sequential injection system,
pay attention to select a pressure regulator properly matched to the given car engine power and
injector nozzles. A pressure regulator that is poorly matched to the car engine power will not be able to
provide sufficient supply of gas at large demand (fully open throttle) and to maintain nominal gas
pressure within the system. Should gas pressure drop below some preset low threshold, the controller
will automatically switch to petrol.
1.12. Selection of injector nozzles
Injector nozzles diameter must also be matched to the given car engine power, see the table below.
Power per cylinder is engine power divided by number of cylinders in the engine.
Nozzle diameter [mm]
reducer pressure 1 [bar]
Power per cylinder range [KM]
1,7 - 1,8
11 - 16
1,9 - 2,2
17 - 28
2,3 - 2,5
29 - 34
2,6 - 2,8
35 - 40
2,9 - 3,0
41 - 48
3,1 - 3,2
49 - 55
The above rough values may in some cases not correspond to actual values.
2. The AC STAG diagnostic program
2.1. Controller-computer connection
Using a RS, USB or Bluetooth NEXT link connect the vehicle-installed (STAG-4 QBOX
BASIC/QNEXT /STAG-300 QMAX) controller with a PC computer on which the Ac Stag diagnostic
program is to be run. Turn the vehicle ignition switch ON to supply the controller with power before
launching the program. This step is required since no communication with the controller is possible
while it is in sleep mode into which it is automatically turned about 10 minutes after its power is
disconnected. As soon as the program is started, the controller links with it (provided the correct COM
serial port is selected). Successful communication is confirmed by the „Status: No ignition switch”,
„Status: Waiting for gas”, „
Status: Petrol
” or „
Status: Gas
” message displayed at the bottom left corner
of the program screen. Parameters window and tabs are presented on figures 13
÷ 16.
If you get the “Controller Error” message and “No connection” appears in the lower left corner of
the screen, select a different COM port from the Port menu at the top of the screen.
