OH NO MY 4.0 IS DIESELING?

I have a 1997 XJ and have been questioning why it is not starting right away. Sometimes i have to try and start it twice. This is intermiten so it does not always do it. But last nite when i tried to start it, it started to turn over and then when i thought it was started it made a clank noise and then stopped. Then i turned it again and it came right back on. My freind said it sounds like it is dieseling. What is the definition of dieseling, and how can this be fixed?

dieseling is when u have carbon built up in the cylinder head and it is igniting the fuel without an ignition source(spark plug)

Adding to the above, back in the days of carburetors, when emission controls were just coming into play, dieseling was pretty common - hot spots in the engine would continue to combust the fuel, and since a carburetor will provide fuel as long as the cylinders pull it, the engine would run on without ignition (very badly). "Anti-dieseling solenoids" became common on carburetors, to shut the idle circuit off with the ignition to prevent this. Dieseling is very rare in fuel injected vehicles, since the fuel supply is controlled electrically. If your engine is running so rich that there is often unburned fuel in the cylinders it might still do it, but this is not common. If this is your problem, you need to find out why it is dumping fuel. A test of the injectors might be a good first step.

JEEPTUBE said:

I have a 1997 XJ and have been questioning why it is not starting right away. Sometimes i have to try and start it twice. This is intermiten so it does not always do it. But last nite when i tried to start it, it started to turn over and then when i thought it was started it made a clank noise and then stopped. Then i turned it again and it came right back on. My freind said it sounds like it is dieseling. What is the definition of dieseling, and how can this be fixed?

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Trouble starting the engine is not dieseling. Dieseling is when you turn off the ignition and the engine keeps running.

THANKU EVERYONE!!

Seafoam. It works. My 97 4.0 was carboned up so bad I had to run premium fuel. Now I use regular again.
Rick