Rough Idle/Engine Stalls at Idle — Always (continued)
F2-34flowchartRough Idle/Engine Stalls at Idle — Always (steps 7-12)
1
STEP 8: Is fuel line pressure correct at idle? (page F2-113) Fuel line pressure: 260—310 kPa (2.6—3.2 kgf/cm2, 37—45 psi) {Vacuum hose to pressure regulator disconnected}
No
Low pressure: Check fuel line pressure while pinching fuel return hose. If pressure quickly increases, check pressure regulator (page F2-113). If pressure gradually increases, check for clogging between fuel pump and pressure regulator. If hose is not clogged, check fuel pump maximum pressure (page F2-110)
Low pressure: Check fuel line pressure while pinching fuel return hose. If pressure quickly increases, check pressure regulator (page F2-113). If pressure gradually increases, check for clogging between fuel pump and pressure regulator. If hose is not clogged, check fuel pump maximum pressure (page F2-110)
Yes: Go to next step
2
STEP 9: Does volume air flow sensor move smoothly from closed throttle position to wide open throttle? (page F2-149)
No
Repair or replace volume air flow sensor
Yes: Go to next step
3
STEP 10: Is there air leakage at intake-air system components?
Yes
Repair or replace
No: Go to next step
4
STEP 11: Is engine compression correct? (section B2) Engine compression (Minimum): 981 kPa (10.0 kgf/cm2, 142 psi)-300 rpm
No
Check for cause (section B2)
Yes: Go to next step
5
STEP 12: Connect System Selector to data link connector and set Test Switch to "SELF TEST"; is ignition timing correct at idle after warm-up? (page F2-71) Ignition Timing (BTDC): 9—11° {10 ± 1°}
No
Adjust ignition timing (page F2-71)
Yes
6
Try a known good ECM and check if condition improves (page F2-141)