Trying to diagnose a 2007 Chrysler Pacifica with 4.0L V6, 132K. Wife's car. Over the last 6 months or so it's developed a hard cranking/long starting condition. It always starts and seems to run fine. It now throws a P0016 code for crank and cam sensors being out of whack. (It also triggers the Traction Control light, which my standard scan tool doesn't read.)
I started with a new AutoZone (Duralast) crank sensor and nothing changed. Put on a Bosch (OEM) cam sensor and nothing changed. It acts like it's not getting fuel at start-up so I tested the fuel pressure and it shows a full 62 PSI once primed. It drops to about 58 PSI while running and remains constant. It does bleed off (loses 14 PSI in the first 5 minutes, loses 34 PSI in the first hour; overnight it loses all pressure.). Based on the bleed-off I was thinking maybe a leaky injector. But, once cleared, the codes come back only while running when the fuel pressure is high and constant. So I'm not convinced it's a fuel delivery issue. Entire fuel system is original, though.
After wiring and sensors, most of the web guidance on the P0016 code suggests the timing has gotten off. The only timing-related reading my scan tool shows is for Ignition "Timing Advance for #1 Cylinder", which at cold idle ranges from around 12.0 up to 17.5. Timing belt and components are 5 years old and have 40K on them and are Dayco from RockAuto. OEM scheduled replacement is around 90K miles.
Any thoughts? Chasing obscure codes isn't fun but I'm trying to figure this out before waiving the white flag and taking it to the mechanic. Unfortunately, there's very little out there in the forums about the Daimler-era 4.0 V6. If you've got an idea, I'd welcome the suggestion. Thanks a lot.
I started with a new AutoZone (Duralast) crank sensor and nothing changed. Put on a Bosch (OEM) cam sensor and nothing changed. It acts like it's not getting fuel at start-up so I tested the fuel pressure and it shows a full 62 PSI once primed. It drops to about 58 PSI while running and remains constant. It does bleed off (loses 14 PSI in the first 5 minutes, loses 34 PSI in the first hour; overnight it loses all pressure.). Based on the bleed-off I was thinking maybe a leaky injector. But, once cleared, the codes come back only while running when the fuel pressure is high and constant. So I'm not convinced it's a fuel delivery issue. Entire fuel system is original, though.
After wiring and sensors, most of the web guidance on the P0016 code suggests the timing has gotten off. The only timing-related reading my scan tool shows is for Ignition "Timing Advance for #1 Cylinder", which at cold idle ranges from around 12.0 up to 17.5. Timing belt and components are 5 years old and have 40K on them and are Dayco from RockAuto. OEM scheduled replacement is around 90K miles.
Any thoughts? Chasing obscure codes isn't fun but I'm trying to figure this out before waiving the white flag and taking it to the mechanic. Unfortunately, there's very little out there in the forums about the Daimler-era 4.0 V6. If you've got an idea, I'd welcome the suggestion. Thanks a lot.
