Diagnostic Procedure 9 — Hesitation under Normal Conditions
EF & EC-442flowchartSR20DE engine. Steps 2 (exhaust gas sensor) and 3 (canister purge) apply to models with catalyzer only.
Diagnostic Procedure 9 — Hesitation under Normal Conditions
1
1. CHECK SPARK PLUGS. Remove spark plugs and check for fouling, etc.
N.G.
Repair or replace spark plug(s).
O.K.
2
2. CHECK EXHAUST GAS SENSOR. (MODELS WITH CATALYZER ONLY) [CONSULT] 1. See 'M/R F/C MNT' in 'DATA MONITOR' mode. 2. Maintaining engine at 2,000 rpm under no-load (with engine warmed up sufficiently), check to make sure that the monitor fluctuates between 'LEAN' and 'RICH' more than 5 times during 10 seconds. RICH→LEAN→RICH = 1 time; LEAN→RICH→...... = 2 times. — OR — [Without CONSULT] 1. Set 'Exhaust gas sensor monitor' in the self-diagnostic Mode II. (See page EF & EC-412.) 2. Maintaining engine at 2,000 rpm under no-load, check that the RED L.E.D. on the E.C.U. or the check engine light on the instrument panel goes ON and OFF more than 5 times during 10 seconds.
N.G.
Replace exhaust gas sensor.
O.K.
3
3. CHECK CANISTER PURGE. (MODELS WITH CATALYZER ONLY) 1. Disconnect canister purge line hose and plug hose. 2. Perform cruise test. 3. Does the hesitation disappear?
Yes
Check purge and vacuum line.
No
4
4. CHECK FOR INTAKE AIR LEAK. When pinching blow-by hose (lowering the blow-by air supply), does the engine speed rise?
No
INSPECTION END
Yes
Discover air leak location and repair.