Irregular Engine

When I start my 1997 Proton Wira Automatics 1.5 (fuel injection), the engine idles run irregularly at alternating high and low rpm. When I switch off and restart the engine, the condition would go back to normal. This occurs occasionally regardless whether the engine is cold or hot. I have used nozzle cleaning additives, changed the air filter and checked the acceleration cable. The normal idling speed of the engine is 750rpm but goes to 1500 during the trouble.

What should the standard ignition timing of my model be? Different woorkshop have given different readings ranging from 5 to 10 degrees BTDC. Will the catalytic converter be damaged through regulsr use? What is its influence on fuel consumption and power output?

Reply:
Modern EFI engines are no longer like the days gone by where any mechanic armed with a screw driver and timing light can sort it out. If one does not have an EFI/Harness checker, any problem solving is really hit or miss. I suggest you take the car to a Proton service centre with all the necessary test equipment. Your problem could be any number of things and I would be guessing what could be your problem and that would be wasting time. Put the ngine through a test cycle and you will find out all that is wrong.

Catalytic converters wear out with use and there will come a time when it will need to be replaced. If you have been running leaded fuel, then the possibilty of it being in ineffective is greater. You can remove it and run a straight pipe in its place but technically you are running illegal engine and you are also adding to the pollution of the atmosphere.