Jaguar Repair: 1986 jaguar warms then cuts off, air flow meter, fuel compression

Question
1986 jaguar warms then cuts off. runs for about 10-15mins then dies. after it sits for a while it cranks normally and does it again after warming. please advise.

Answer
Hi DJ,
Your symptom narrows the problem down to only a thousand possibles so you need to so some testing when it is in it's failed mode.
All engines only require 3 items to run, compression, fire and fuel. Compression will not usually go and come back like that so you need to look at fire and fuel.

Fire is the easiest to test so look at that first by putting a timing light on a plug wire and spin the engine over when it will not start. If the light flashes then you need to get a fuel gauge and a "T" fitting and put the "T" fitting in the fuel line just before the fuel rail and put the gauge on the line from the "T" fitting. (be sure to put clamps on all the joints) You will need a fuel gauge that can read up to 50 PSI at least. Then run the car until it fails and read the fuel pressure by removing the air filter and turn the key on and reach your finger in the front of the air flow meter and open the flap inside. The fuel pump should start running and it should read about 42 PSI. When the car was running the pressure should have been about 32 PSI.

These two basic tests will tell you if the problem is fuel or fire related. Once you establish that, let me know and I will give you the next series of tests to run.
Howard