Monday, February 14, 2011

Engine Trouble-Shooting

Pinging or detonation type of engine noise

- Some things that can cause knocking are timing advanced too far, excessive engine heat. to lean a fuel mixture. All of these can be dependent on other things.

-- Things to look for are bad knock sensor, one or more injectors that are gummed up causing a lean condition in one or more cylinders, thermostat that is causing the engine to run to hot. Low fuel pressure causing lean condition.

-- A good place to start is with one of the $100.00 or so pc-based scan tools and one of the $100.00 dollar or so programs. This will let you monitor the outputs and interaction of many of the sensors in the engine.

-- You can pull the plugs and read them by the color and condition to see if you have a single cylinder that is running lean.

- Check the wiring on the fuel injectors. Could be a wire that is not obviously loose and the fuel to timing ratio is off. Be sure to look for splices and electrical plugs. If electric plugs, disconnect and look for corrosion. Also gently tug on any splices and if the wire appears to move out of the splice (any amount) re-splice it. You do need to remove the dog house to check the wiring to the fuel injection rail.

- To start with I would run a good brand of fuel injector cleaner through a tank or two of gas. I might even have a good shop do one of the fuel system cleaning procedures done on the engine.

- Try a higher octane tank of gas to see if that changed symptoms.

- Assuming you're using 87 octane gas, you might want to have a cylinder compression check done.

Contributors: Gary McNeil, Joan Taylor, Garry Foster

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