My old 2000 XJ8 (320k km) failed to start last night. Sounded like no compression. I figured I would be pulling the plugs and squirting oil in the cylinders today. I tried just cranking the engines and putting gas in the throttle and I did get it to run but as soon as the gas burned out it died. I did re start it by pumping and and it never ran above idle but as soon as my leg got to tired it died again. I will check the fuel pump next but that should not have caused the original issue and the odds of it breaking down at that moment seems odd. Obe Two Kenobe says I have multiple misfires and o2 module failure. Any other ideas

 

I would star with the fuel pump. Check the pressure at the schrader valve on the fuel rail by turning the ignition on and depressing the valve with a rag stuffed around it to catch the fuel. You should have a strong spurt of fuel.

 

Tilbury,
The fuel system for the engine starting works like this. When the key is first turned on the fuel pump runs for 3 to 5 seconds and then shuts down. When the engine starts the ecm takes over and turns the fuel pump on. To test I would first turn the key to on (not starting) wait 5 seconds turn it off and repeat 3 times. Then check for pressure at the schrader valve. If you have pressure then repeat once more and go to the cranking with no pedal. Does it start and die or do you get no start?
Before going into removing the tank and changing fuel pumps I would check the fuse for the pump, check the relay (by swapping) for the pump and change the fuel filter.
Give it a go and get back to us with results.

 

good advice here from RJ and avern. You can jump out the relay and you should hear the fuel pump running. If you have never changed the fuel pump with 320K km that is likely the problem

 

Have you had the timing chain tensioners done?

 

I had a face palm moment. I went back out to car, looked at the engine and saw I still had the air intake runner removed. I installed it on the throttle body and it started right up. I still am reading misfirings and o2 sensor faults. I am going to swap o2 wiring plugs and see if the fault swaps sides. What causes this bore wash. I don't touch the gas before starting and the engine ran for a moment before it stopped a couple days ago prompting this round of trouble shooting..

 

Clear the codes. They probably were set when you disconnected the air tube giving the ECU false readings from the MAF to compare with the O2 sensors.

 

Bore wash is usually the result of shutting the engine off before it warms up to open loop operation. The rich fuel mixture washes the oil off the cylinders and compression drops too low.

 

A hard reset might help. Disconnect negative cable from the battery and touch it to the positive post for a few seconds.