Experiencing Dieseling Problem?
B21F Engine – 240 Fuel Filter Location
Disconnect the battery negative lead making sure that you have the radio code if applicable. In the luggage compartment lift the carpet and you will see an inspection plate in the floor. Remove the plate to see the top of the sender unit. Disconnect the earth (ground) wire and the lead from the sender unit terminal. The sender unit is held in place by a locking ring which can be taken out with a special tool or by using a piece of hard plastic and a hammer. The plastic is to prevent sparks. Place it in one of the cut-outs in the ring and gently tap it until the ring comes loose. Lift the sender unit out of the tank. It is possible to make the tool if you want to.
The filter is on the very end of the unit. When replacing the sender you need a new gasket.
Dieseling was a common problem on carb engines and can be caused by:
1. Incorrect timing. 2. A carburettor that does not close entirely can contribute to running once the engine is off, since the extra fuel and oxygen mixture can combust easily in the warm piston chamber. 3. An improperly rated spark plug can retain heat and cause the problem. 4. An engine that runs too hot or too lean may produce an environment conducive to allowing unspent fuel to combust. 5. An idle speed that is too fast can leave the engine with too much angular momentum upon shutdown, raising the chances that the engine can turnover and combust more fuel and lock itself into a cycle of continuous running. 6. Hot vaporized oil gases from the engine crankcase can provide ample fuel for dieseling. 7. Built-up carbon in the ignition chamber can glow red after the engine is switched off, providing a mechanism for sparking unburnt fuel. This can happen when the engine runs very rich, depositing unspent fuel and particles on the pistons and valves.
The MVS Volvo Newsletter is a once-a-month email delivered to your email. It’s simple to unsubscribe at any time if you change your mind.