96 XJ, 4.0L, AW-4, 124k miles, no CELs, new coil, dist, plugs, wires within last year.

Once warm it takes a while to start back up, like 10 seconds of cranking. Starts perfectly when cold. Once running, it runs great.

I know this sounds like a leaking injector, but this happens even if I try to start immediately after shutting off. And I can't imagine an injector is leaking that much in only 3 to 5 seconds.

Any thoughts? Don't want to buy new injectors if it's likely the CPS or coolant temp sensor. Anyone had the same problem?

TIA

 

The coolant temp sensor is definitely a suspect and needs to be ruled in or out right away. It's suspect whenever there is a problem with starting either with a stone cold engine or a hot engine. When the engine finally does start with a hot start, does it start CLEAN or does it stumble for a few seconds?

The CTS can be tested for resistance values when the engine is cold/hot. The testing procedure will tell you to remove sensor, place in a pan of water with a calibrated thermometer and heat water and measure resistance. Because that is a PITA, what I generally do is to measure resistance while the sensor is still installed in the vehicle. Measure cold, then hot, then compare both of those numbers to the resistance chart located in all maintenance manuals. If they are "close", the problem probably lies elsewhere. There should be a very wide range in measured values between a cold and hot engine when measuring the CTS. The sensor isn't that expensive if you would just like to replace it.

This does not sound like a crank sensor issue or fuel injector issue to me.