High fuel consumption
Step 1: Is ignition system in proper condition?
Check battery voltage, ignition distributor, spark plugs, ignition coil, ignition timing, etc.
Yes: Go to Step 2
No: Repair or replace damaged ignition components
Step 2: Is engine in proper mechanical condition?
Check for mechanical problems: Compression, basic adjustment of valves and engine oil pressure.
Yes: Go to Step 3
No: Repair or replace damaged components
Step 3: Is the fuel pressure correct?
Yes: Go to Step 4
Step 4: Is the quantity of fuel delivered by the injectors correct?
Remove one valve at a time and inject fuel into a graduate for 30 seconds while engine idles. Compare quantity with that delivered by a known good injector. If quantity deviates from good injector, original valve was defective.
Yes: Go to Step 5
No: Replace defective injector
Step 5: Is the start valve in proper condition (no leaks)?
Yes: Go to Step 6
No: Go to Step 5-A
Step 5-A: Is the cold start valve leaking fuel?
Test the start valve for leaks. For this purpose clamp the fuel intake line closed with a clip. Does engine then run evenly?
Yes: Replace start valve
Step 6: Is the air flow meter in proper condition?
For testing, see under Engine does not start under Step 9.
Yes: Go to Step 7
Step 7: Is composition of exhaust gas (concentration of CO) correct?.
See the Air flow meter test Chart for value.
Yes: Go to Step 8
No: Adjust CO
Step 8: Is the altitude compensator functioning correctly?
The altitude compensator is installed in some vehicles operated at high altitudes. Check according to Altitude compensator test chart.