Hi I have a KH laser that will fire and run for a second or 2 and stop
I have tried 3 carbys, replaced head gasket, checked compression (No 4 a little low but should be ok.) I have pressurised each cylinder with compressed air about 60 psi (no leaking valves.) replaced plugs. coil lead throws a blue spark about 2 inches if you crank over and you earth it out. Have checked and double checked the timing belt marks I have swapped coil and distributor. It sounds like it fires and runs out of fuel. pump works fine and have checked filter. It fires up a bit better if you have distributor advanced as much as it will twist but just dies after it fires and tries to run. all leads are in correct firing order (double checked.) I am stumped, I have spent three days and no joy. After it has fired and stopped it has a low hissing noise come back through the carby (pressure of some sort.) this may be normal I don't know. If anyone has a solution I am all ears. Please help I am going nuts

Does it have a Ballast Resistor ????...it may be failing.
Checked for vacuum leaks ???
Is it auto or manual ???
If it's auto, check the vacuum line that goes to the tranny, vacuum modulator, see if it has been sucking up tranny fluid.

It is manual have searched for vacuum leaks found none so far. But ballast resistor I have no idea will have to look into it . Thanks for the ideas

Hi,

The ballast resistor is normally white ceramic and about 25mm by 100mm or so. A wire at each end. Another way to test it is to turn the ignition on, without trying to start. Get a Multi-meter and test the Voltage at the Coil at the + terminal. It should be around 9 Volts. Not sure about Escorts, but some early Falcons had resistance wire in the Loom which did the same thing.

The reason they have it is this. As you crank the engine the battery voltage drops. This means a weak spark. We use a Coil that runs on about 8 Volts to get a good spark. When the engine fires, the resistor keeps the Coil at about 8 Volts. The Coil would overheat and fail if we didn't.

The Exhaust, it could be blocked. If you are sure the Ignition is right, drop the Exhaust at the manifold. There may be a baffle in the muffler that has come loose.

Re-check what you have done, when things are not going well and you start swapping things, it is easy to make mistakes or fit faulty parts. An engine will run from a spray bottle of petrol aimed into the Carb. You can do this to eliminate the entire Fuel system. Only use a small amount, a backfire can make you human fireball !

I hope this will help, report back with what you find.

Hi,
It was blocked exhaust. what a lot of work for such an easy fix. Thanks for your help much appreciated.