Latest cars in the workshop

We looked at a Ford Cosworth Race Car just before it went to Brands Hatch on the trailer to race for the weekend.
Once fired up it was obvious there was something wrong.
Not all the cylinders were firing.
These cars are far from complex and simple time tested methods can work quickly.
Pull off the injector connector for each cylinder in turn, the missing cylinder will have little effect on the engine tone. You may not notice much in the way of a rpm drop as the idle stepper motor will keep the idle speed stable.
But you will notice the difference in engine tone.
Having diagnosed cylinder number 1 as the problem, the next step is to find out why.
You need 3 elements to make an engine run;
fuel.
spark.
compression.

Swopping the injector connector with cyl 2 did not move the problem so a fault within the fuel system could be quickly ruled out.
That left the ign and engine condition.
A quick spark check showed a spark at the end of plug lead. But that isn't the end of the spark test. We need to make sure its not the plug. Simple (on these cars) whip out the plug and see if it sparks when earthed while the engine is running.

While the plug is out carry out a quick compression check, compare results with a running cylinder if the cranking pressure is unkown.
In this case the plug had failed.

Using an automotive scope and amps clamp would of proved the fault much quicker and prevented miss diagnosis.