Keep on running !! - Page 2

Clifford Pope · Jun 8th, 2006, 08:21

Chris has said it - if the ignition is off it has to be caused by something in the combustion chamber being hot enough to ignite the mixture anyway. That could be carbon build-up, or an incorrect spark plug running too hot, or possibly an exhaust valve overheating.
Overheating could be caused by a weak mixture, air leak, incorrect ignition timing, cooling fault, such as choked radiator or partial blockage in the water passages in the cylinder head. I suppose a faulty condensor could cause an ignition fault that in turn might lead to overheating.
Are you sure the fuel cut-off really does cut off? Could the valve be leaking? Many cars don't have them, and don't run on, but presumably it was fitted in this case because of a known tendency.
Another classic cause is simply the idling speed being too high. I'm not sure why that is.
Could be the fuel is burning too hot, eg if you are using an unnecesarily high octane like super-unleaded when it doesn't need it.

ivor940 · Jun 8th, 2006, 10:28

Hi, Mk 1 Fiestas and Mk3 Escorts had a "Run on" snag which was fixed via an electric Solenoid and pipe which let in air to the Inlet manifold when the engine was shut down. This made the mixture too weak and the engine could not run on.

ivor940

Jun 8th, 2006, 08:21	#11
Clifford Pope Not an expert but ... Last Online: Today 08:06 Join Date: Dec 2001 Location: Boncath	Chris has said it - if the ignition is off it has to be caused by something in the combustion chamber being hot enough to ignite the mixture anyway. That could be carbon build-up, or an incorrect spark plug running too hot, or possibly an exhaust valve overheating. Overheating could be caused by a weak mixture, air leak, incorrect ignition timing, cooling fault, such as choked radiator or partial blockage in the water passages in the cylinder head. I suppose a faulty condensor could cause an ignition fault that in turn might lead to overheating. Are you sure the fuel cut-off really does cut off? Could the valve be leaking? Many cars don't have them, and don't run on, but presumably it was fitted in this case because of a known tendency. Another classic cause is simply the idling speed being too high. I'm not sure why that is. Could be the fuel is burning too hot, eg if you are using an unnecesarily high octane like super-unleaded when it doesn't need it.

Jun 8th, 2006, 10:28	#12
ivor940 Master Member Last Online: Sep 16th, 2013 07:55 Join Date: Dec 2003 Location: Malahide View Photos By: ivor940	Hi, Mk 1 Fiestas and Mk3 Escorts had a "Run on" snag which was fixed via an electric Solenoid and pipe which let in air to the Inlet manifold when the engine was shut down. This made the mixture too weak and the engine could not run on. ivor940

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