Installed new injectors, now it won't stay running

scotty305 · 12-11-2010, 02:13 AM

Blipping the throttle usually adds extra fuel for acceleration enrichment, if this is helping the engine stay running I would suspect the main fuel map is far too lean.

Assuming the old 1000cc/min injectors had resistors installed, did you remove the resistors when changing to the new injectors? Running high-impedance injectors with ballast resistors would screw with their opening times and could account for this sort of behavior.

Also, the fuel map should need about 30% fuel added, assuming the injector latency/deadtime/battery offset compensation was correct for the old injectors and has been adjusted correctly for the new injectors. Sorry I haven't used a PFC so I won't know the exact option names or values to use.

For what it's worth, my car (stock engine, stock ports) ends up at 2-3ms of fuel injector pulsewidth at idle using ID1000 primary injectors. If you're below that with your 725's, you should definitely add some fuel.

12-11-2010, 02:13 AM	#2
scotty305 Rotary Fan in Training Join Date: Mar 2008 Location: Culver City, CA Posts: 84 Rep Power: 18	Blipping the throttle usually adds extra fuel for acceleration enrichment, if this is helping the engine stay running I would suspect the main fuel map is far too lean. Assuming the old 1000cc/min injectors had resistors installed, did you remove the resistors when changing to the new injectors? Running high-impedance injectors with ballast resistors would screw with their opening times and could account for this sort of behavior. Also, the fuel map should need about 30% fuel added, assuming the injector latency/deadtime/battery offset compensation was correct for the old injectors and has been adjusted correctly for the new injectors. Sorry I haven't used a PFC so I won't know the exact option names or values to use. For what it's worth, my car (stock engine, stock ports) ends up at 2-3ms of fuel injector pulsewidth at idle using ID1000 primary injectors. If you're below that with your 725's, you should definitely add some fuel. Last edited by scotty305; 12-11-2010 at 02:17 AM.