Long start after engine change

[KBO]

Like the title states, jeep has a long start after the engine was changed. The long start happens after driving for around 30 mins or so. It starts after about 3-5 seconds of cranking. During the engine change they replaced the fuel injectors, cam position sensor, spark plugs, cam shaft synchronizer and other items.
During the troubleshooting they have replaced the fuel pump, CPS and replaced the fuel injector connectors (cracked wire insulation). I have the DEI manifold heat shield and injector wraps installed. Any help would be greatly appreciated. Trying to give the shop an idea of where to go next.

 

[Steel City 06]

Have they tested the fuel pressure after shutdown? If you hook up a pressure gauge, the fuel pressure should stay constant even after the fuel pump turns off. If the pressure is leaking down after fuel pump shutoff, then that could cause an issue.

 

[Steel City 06]

Actually, rereading this, search "heat soak" on this forum. That sounds exactly like this. Basically the heat from the engine boils the fuel inside the injectors after the engine is shut off, so it takes an unusually long time to restart as you have to purge the vapor to get liquid fuel spraying out.

Looks like you have the injectors wrapped already. There are also kits to insulate the fuel rail as well

 

[Steel City 06]

In addition, if they have done anything that modified the relation between the camshaft synchronizer and the crankshaft position sensor, there is a PCM relearn procedure that needs to be done to reset the calibration between the two.

This cannot be done by simply unplugging the battery from the PCM. You need a diagnostic tool like the Snap-On, Autel Maxicom, or similar to do the reset. Basically this tells the PCM that the relation between the two is different, and now it needs to learn the new position to run properly.

 

[KBO]

In addition, if they have done anything that modified the relation between the camshaft synchronizer and the crankshaft position sensor, there is a PCM relearn procedure that needs to be done to reset the calibration between the two.

This cannot be done by simply unplugging the battery from the PCM. You need a diagnostic tool like the Snap-On, Autel Maxicom, or similar to do the reset. Basically this tells the PCM that the relation between the two is different, and now it needs to learn the new position to run properly.

Thanks!
I’ll ask them about this. They haven’t mentioned doing this.

 

[KBO]

Actually, rereading this, search "heat soak" on this forum. That sounds exactly like this. Basically the heat from the engine boils the fuel inside the injectors after the engine is shut off, so it takes an unusually long time to restart as you have to purge the vapor to get liquid fuel spraying out.

Looks like you have the injectors wrapped already. There are also kits to insulate the fuel rail as well

I have the fuel rail piece (not installed) and plan on giving it to them to install. I also ordered the fuel line wrap.
Before the engine swap l hadn’t ever experienced a long start.
Not sure if it’s related but after the engine swap I have a P1494 code (emission leak detected)

 

[KBO]

In addition, if they have done anything that modified the relation between the camshaft synchronizer and the crankshaft position sensor, there is a PCM relearn procedure that needs to be done to reset the calibration between the two.

This cannot be done by simply unplugging the battery from the PCM. You need a diagnostic tool like the Snap-On, Autel Maxicom, or similar to do the reset. Basically this tells the PCM that the relation between the two is different, and now it needs to learn the new position to run properly.