Usualy a slow start is down to the IAC (Idle air control valve)..Mines screwed, and can take upto 15 seconds to start. (Somedays are better than others)
Two ways to test:
pull the code - Underneath your steering columb, theres a black and green connector. hook the black to black. Turn your car to ignition but dont start..You car will blink a code with its CEL (its like morse code, so two long and 4 short is the ECU saying the IAC
http://www.scoobypedia.co.uk/index.php/ ... ngECUCodes
Test two - turn the key to start for just 1 rotation. Let it go back to ignition and try to start it again. What this does is lets the ECU know it didnt start, so it opens the IAC all the way. Sometimes like mine they get stickey and dont like to move little bits. The ECU will pull it WAYY out.
Let us know how you go
Code ITEM
11 Crankshaft position sensor
12 Starter switch
13 Camshaft position sensor
21 Engine coolant temperature sensor
22 Knock sensor
23 Mass air flow sensor
24 Idle air control solenoid
31 Throttle position sensor
32 Oxygen sensor
33 Vehicle speed sensor 2
35 Purge control solenoid valve
42 Idle switch
44 Wastegate control solenoid valve
45 Pressure sensor –Pressure exchange solenoid valve
51 Neutral position switch
Other Subaru Codes
These codes are not documented in the Impreza Workshop manual but are mentioned in other Subaru Documentation (and can be decoded by a Select Monitor), these may or may not be applicable to the Impreza.
Code ITEM
11 Crank angle Sensor or Circuit
12 Starter Switch or Circuit
13 Cam Position Sensor or Circuit (TDC Sensor on Justy)
14 Fuel Injector No. 1 (Legacy, Impreza, Justy, SVX)
15 Fuel Injector No. 2 (Legacy, Impreza, Justy, SVX)
16 Fuel Injector No. 3 (Legacy, Impreza, Justy, SVX)
17 Fuel Injector No. 4 (Legacy, Impreza, SVX)
18 Fuel Injector No. 5 (SVX)
19 Fuel Injector No. 6 (SVX)
21 Coolant Temperature Sensor or Circuit
22 Knock Sensor or Circuit (Right Side on SVX)
23 Air Flow Meter or Circuit (Exc. Justy)
24 Air Control Valve or Circuit (Exc. Justy)
25 Fuel injector No. 3 and 4 (XT-6)
26 Air Temperature Sensor (Justy)
28 Knock Sensor No. 2 (SVX, Left Side)
29 Crank Angle Sensor (SVX, No. 2)
31 Throttle Position Sensor or Circuit
32 Oxygen Sensor or Circuit (No. 1, Right Side, On SVX)
33 Vehicle Speed Sensor (VSS) or Circuit
34 EGR Solenoid or Circuit
35 Purge Control Solenoid or Circuit
36 Air Suction Solenoid Valve (Impreza)
37 Oxygen Sensor (No. 2, Left Side, On SVX)
38 Engine Torque Control (SVX)
41 Air/Fuel Adaptive Control
42 Idle Switch or Circuit
43 Throttle Switch
44 Wastegate Duty Solenoid (Turbo Models)
45 Pressure Sensor Duty Solenoid (Turbo Models)
45 Atmospheric Pressure Sensor or Circuit (Non-Turbo Models)
46 Neutral or Parking Switch or Circuit
47 Fuel Injector
49 Airflow Sensor
51 Neutral Switch (Manual Transmission Models)
51 Inhibitor Switch (Automatic Transmission Models)
52 Parking Brake Switch (Exc. Justy)
53 Fuel Pump or Circuit
54 Choke Control System
55 EGR Temperature Sensor or Circuit
56 EGR System
57 Canister Control System
58 Air Control System
61 Fuel Tank Pressure Control Solenoid (Impreza)
62 Fuel Temperature Sensor (Impreza)
63 Fuel Tank Pressure Sensor (Impreza)
64 Vacuum Line Control Valve or Circuit
65 Vacuum Pressure Sensor
66 Sequential turbo system
67 Exhaust valve solenoid (positive pressure)
68 Exhaust valve duty solenoid
71 Ignition Pulse System
73 Ignition Pulse System
74 Ignition Pulse System
88 TBI Control Unit