intermittent long start... fixed.

I had begun seeing this earlier in the summer, but only a couple times a week. Didn't matter if the car had been running recently or if it was the first start of the day... the engine would turn over fine, but would simply crank for 3 - 4 seconds before finally firing. No lights or DTCs.

First step was to take it to the dealer. Their recommendations revolved around "carbon build-up" in the throttle body, clogged fuel injectors, and spark plugs that had 60k miles. Since the start-up delay was completely random and the length of the delay was like clockwork, I figured it had to be something electrical that was putting the PCM into some temporary mode.

A powertrain engineer at Chrysler first had me look at the battery voltage, since there's a "rollback detection" that can be mis-triggered if the battery is low and the rpm during crank is too slow. Basically, the sensors can't determine rotational direction, only speed... so if the engine rpm matches what is known to be the backwards rotation of the crank following a backfire, the PCM will not deliver fuel. This was not the issue in my case.

Next, I tried the crank position sensor swap. Like I said, there were no DTCs but my issues were similar enough to other posters that I thought it was worth a try (and the sensor was only $24). My car is a RWD w/ the starter on the passenger side of the engine. It is absolutely necessary to remove the starter in order to get to the crank sensor on my car... it's tucked directly above the starter motor. 3 bolts and the starter is out, then the biggest pain is the sensor connector. This did not fix my starting issue.

Finally, I picked up the cam sensor and did that swap ($20). So easy I wish I would've done it before trying the crank sensor... Oh well. I did the cam sensor on Monday, and I haven't had the issue since. I'm confident that this was the culprit. The original sensor had no visual damage, so it was just a flakey signal that caused the PCM to mis-trust it from time to time.

Intermittent signals from either the crank or cam sensor can apparently cause this issue, so I'm glad I checked both. The PCM will not deliver fuel until the engine position is determined (cam/crank sync is achieved). Once engine position is determined, the cam is not referenced again. The pattern between the cam and crank signals needs to be of "good" quality in order for the PCM to be happy. No lights or DTCs unless the issue occurs two times in a row.