Diagnostic Procedure 3 — Unstable Idle (Cont'd)
EF & EC-433flowchartIdle rpm set in "N" position (A/T-relevant phrasing).
Diagnostic Procedure 3 — Unstable Idle (Cont'd)
1
CHECK FOR INTAKE AIR LEAK. When pinching blow-by hose (lowering the blow-by air supply), does the engine speed rise?
Yes
Discover air leak location and repair.
No
2
CHECK IDLE ADJ. SCREW CLOGGING. 1. Perform "IGN TIMING ADJ" in "WORK SUPPORT" mode. 2. Can you set engine rpm at 800±50 rpm (in "N" position) by turning idle adjusting screw? — OR — 1. Disconnect throttle sensor harness connector. 2. Can you set engine rpm at 800±50 rpm (in "N" position) by turning idle adjusting screw?
No
Check for I.A.S. clogging or throttle valve clogging.
Yes
3
CHECK COMPRESSION PRESSURE. Check compression pressure. Standard: kPa (bar, kg/cm2, psi)/300 rpm 1,275 (12.75, 13.0, 185) Minimum: kPa (bar, kg/cm2, psi)/300 rpm 1,079 (10.79, 11.0, 156) Difference between each cylinder: kPa (bar, kg/cm2, psi)/300 rpm 98 (0.98, 1.0, 14)
N.G.
Check pistons, piston rings, valves, valve seats and cylinder head gaskets.
O.K.
4
CHECK E.C.U. HARNESS CONNECTOR. Check the E.C.U. pin terminals for damage or poor connection of E.C.U. harness connector.
N.G.
Repair or replace.
O.K.
5
TRY A KNOWN GOOD E.C.U.*
INSPECTION END
NOTE
*: E.C.U. may be the cause of a problem, but this is rarely the case.