Crank no start frustration!

[Matthew Aguilar]

Okay so, I’ve attempted to diagnose this crank no start but have gotten no where. I verified fuel pressure at the rail so I know it’s not a fuel issue. When I pulled the coils to check the spark plugs I noticed the spark tubes had all been almost melted and the coils cracked, surly I thought this was the source of my concern. Replaced coils and tubes. Now it will crank for about 10 seconds and attempt to start only at WOT. It will run for about a 2 seconds after key is out of crank position, again only at WOT. I hooked up a scan tool and pulled DTC P1397. I’ve check the wires going to the DME and found no opens or shorts. I have 5v ref, good ground and on the signal wire I have 12v coming from the DME. Other forums said this is correct operation. I replaced the sensor, code still present. Crank no start concern still present.

[JFP in PA]

2 hours ago, Matthew Aguilar said:

Okay so, I’ve attempted to diagnose this crank no start but have gotten no where. I verified fuel pressure at the rail so I know it’s not a fuel issue. When I pulled the coils to check the spark plugs I noticed the spark tubes had all been almost melted and the coils cracked, surly I thought this was the source of my concern. Replaced coils and tubes. Now it will crank for about 10 seconds and attempt to start only at WOT. It will run for about a 2 seconds after key is out of crank position, again only at WOT. I hooked up a scan tool and pulled DTC P1397. I’ve check the wires going to the DME and found no opens or shorts. I have 5v ref, good ground and on the signal wire I have 12v coming from the DME. Other forums said this is correct operation. I replaced the sensor, code still present. Crank no start concern still present.

P1397 Camshaft Position Sensor 2 - Signal Implausible, Short to Ground, Short to B+

Potential causes:

- No power supply.

- Short circuit to B+

- Short circuit to ground.

- CMP sensor faulty

Check the wiring...

[Matthew Aguilar]

On 9/18/2024 at 3:13 PM, JFP in PA said:

P1397 Camshaft Position Sensor 2 - Signal Implausible, Short to Ground, Short to B+

Potential causes:

- No power supply.

- Short circuit to B+

- Short circuit to ground.

- CMP sensor faulty

Check the wiring...

I checked the wiring. Only thing I’m not sure about is pin 2 the signal wire had 12v coming out of the dome going to the cam sensor connector. Pin 3 had 5v and pin 1 had non. I ohmed pin 2 for a possible short to b+ and found no short. Is the DME suspect?

[Loren]

Could also be the cam position sensor itself.

 

[Matthew Aguilar]

On 9/22/2024 at 11:47 AM, Loren said:

Could also be the cam position sensor itself.

 

I already replaced it. I noticed the tube from the AOS had a hole in it so I replaced it. Now today after cranking multiple times I was able to get it to idle very roughly any throttle killed it. Any ideas? Could that code lead to a mechanical failure? The vario pads worn?

[Matthew Aguilar]

Update: I removed the cam cover bank 2 for the given code and found the Variocam pad completely destroyed and missing. With the cams removed I counted the timing jumped three teeth. Installed new cam pads and it fired up. Slight misfire cylinder four.