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Truck came into the shop with a customer complaint of screeching noise on startup and rough running.
Had codes PO335 PO336
Truck was brought in obviously in at operating temp state. No noise or rough running was noticed.
Crank the truck the next morning and Holy cow. Sounds like the bendix in the starter is hanging up on the flex plate and it is running awful. last about 20 -30 seconds and clears up and runs great. I crank and crank to try and get the starter to hang up or make the awful noise again. Note code PO335 is current.
I probe the crank sensor and note a perfectly good looking AC sign wave on the two wire VR crank sensor.
I let the truck sit the rest of the day and go to crank it again. Bam awful noise and rough running. "This time it stalls out and has and extended crank back." Wave form looks normal on the crank sensor. I mess with it on and off and notice its an issue that Only seems to show it self on a cold start.
Little bit of service data shows the pcm controls cranking its looking for 300-400 rpm. My train of thought is that this might be a leaky fuel injector flooding it out while it sits for extended period of time. In return this causes a misfire rough running and ultimately a phantom crank code and the pcm to keep the starter engaged to long. Fuel pressure gauge does not show a immediate drop in fuel pressure but over long periods on time " few hours" it will go from 58 psi primed to <30. Seen it as low as 18 in about a 4 hour sit with the gauge on it. I primed the system with the gauge and will let it sit over night to recheck in the morning.
Looking for advice on things to check, or maybe I am completely in the wrong ball park on tracking down this issue.
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