The engine in my 1984 firebird wont stop turning over after key release
If you are talking about engine cranking, then you should check for free operation of the starter motor solenoid. This is situated on the top/side of the motor and it\'s job is to engage the starter motor only when the ignition key is turned to the crank position. It is plausible that the solenoid has become corroded, or fused in the closed circuit position.
To check to see if this is the case, remove and clean the starter motor solenoid, and test it\'s operation while off the car.
If you are talking about continuous running, not cranking, then you will best use an endoscope and insert it into the engine\'s cylinders to view the innards. You are looking for a build up of carbon on either the valves, valve stems (when in the open position), pistons, and cylinder head. Also check the condition of the spark plugs for a build up of carbon.
Carbon is a byproduct of combustion, and can build up on some internal engine surfaces. This can cause a number of issues when running. The carbon becomes red hot and can retain it\'s temperature for a long period of time. When you turn off the engine in a carburetor vehicle, then air and fuel can still be drawn into the engine while its momentum winds down. However as the red hot carbon in the cylinders is hot enough to ignite the fuel and air mixture, the engine still runs, still turns and continues to suck in more air and fuel mixture, and continues to operate.
It may operate quite roughly and eventually stall out, as the fuel/air mixture isn\'t as efficiently burned when ignited by hot spots, and the hot spots may eventually cool enough to fail as an ignition source.
These two above examples are perhaps a couple of the most common reasons for an engine continuing to run after the ignition key has been turned to the off position, or has even been removed from the lock/barrel.
The only final reason for the engine managing to keep running after the key has been removed, is a faulty ignition lock/barrel mechanism.
Nov 18, 2012 |
1984 Pontiac Firebird