2018 Ram Big Horn, 5.7L Starting Issue

[ldgguy]

I have been having an intermitent starting issue for the last several thousand miles. I have replaced the four-year old battery during this time as well to rule that out.
Every once in a while it will attempt to start and it sounds like it isn't getting any gas. It will turn over for about 10 seconds and then stop. When I try again it will start right up. Sometimes when it starts it has a quick "zap" or "snap" sound. Everything is factory, there is no aftermarket anything on it. I have tried using several tanks of 89 octane gas as well as 87 with no difference. I searched previous posts but can't find anything similar to this issue.
It can do this when I start it with the key or with the remote factory start from the key fob. It can do it when it is cold outside or in the middle of the summer and it may do it when the vehicle has been sitting overnight or when it is warm and restarted.
If you have any tips/thoughts for me to try or other suggestions I would appreciate it.

 

[Mister Luck]

My first guess would be

Camshaft position sensor
and or
Crankshaft position sensor

But before you throw parts at your vehicle
Have a OBD port reader to give you a more accurate assessment and if the sensors have pending codes for example
like a P0335 or a P0340

If you don’t smell fuel under the hood or in your oil it could still be a problem with the fuel pump but that would normally give an error code.

 

[Ram Night]

This almost sounds like the fuel pump relay or pump is failing. There have been issues of the pump relay failing on these trucks and other cars. So a search and you will find a lot of information on how to test the relay with a couple of simple fuses tap jumpers. And instructions and diagrams on installing a $10.00 remote relay and harness there is only 4 wires to connect under the fuse panel box (TIPM) by the battery.

Plus there will be no error code because the PCM will be sending the run signal to the relay so it thinks everything is ok.