It's the crank sensor!
Join Date: Nov 2007
Location: Central Minnesota
This thread lays out my problem and how to fix on a YJ - does any one know if it would be different on an XJ? I imagine the solution would be but are the tests to get to that point also in line?
Problem: Will crank but doesn't start until CEL + Fuel Pump Prime
Always start with posting the year/engine of your xj as there are significant differences throughout the years and the accuracy of the replies depends on the year/engine.
It is best to start fresh so that we know exactly what is going on. Please elaborate on your symptoms.
1. I am confused when you say " will crank but doesn't start until CEL and fuel pump prime". CEL stands for check engine light. How exactly is your check engine light involved here?
2. Does your xj have an "extended crank time" before it fires up when the engine is cold?
3. If you try the "poor mans prime", does that help? Poor mans prime: Turn the key to the on position. Fuel pump will energize and run for 2 seconds. Turn key to the off position. Repeat the above steps twice more. NOW crank the engine. Does it start quickly when you do this? If so, you are experiencing fuel pressure drop somewhere. Could be a leaky check valve, could be a different leak, leaky fuel injector, etc.
4. Does it start fine when the engine is hot?
99 Cherokee, 4.0 AW4, NP242
Past Jeeps: 49 Willys, 81 Scrambler, 88 Comanche
Without "data", all you have is an opinion!