2012 5.7L 2500 Ram cranks but won't start

Hey everyone,

My truck has about 57k miles on it and I use it on my farm. The other day it cranked and had a rough start. It idled really low for a few seconds but after pumping the gas it was fine.

I drove it about 10 miles to the farm and when I was done feeding the cattle it cranked but wouldn't start. It seemed to ignite the first time but it just died and went back into cranking. I'm assuming it has a spark or it wouldn't have ignited and the battery is fine so I'm guessing it's the fuel delivery.

Does anyone have any ideas as to why it wouldn't start? I'm going to use my other key and check all the fuses but since it had rough idling and it ignited for a second afterward I am guessing it's a fuel delivery issue and it's probably the fuel pump.

Any help would be greatly appreciated.

If you got no check engine lights, sounds like a fuel pump. I would still get it scanned to see if you got any pending codes for misfire or other ignition related issues to be safe.

Still might be worth the effort to have a tech check the fuel pressure, spark and air systems before shotgunning a fuel pump into it.

How cold is it? Have the plugs been changed? As plugs wear the gap gets bigger and causes hard starting especially in cold temps. Can you hear the fuel pump buzz turning the ignition to run? If not have someone rap the tank with a mallet while you crank it. If it wants to run with a shot or 2 of fuel injector cleaner in to the throttle body then you're probably right, fuel pump.

Check to make sure all the fuses are good. Use a test light to see if there is power on the fuel pump fuse while cranking. I have seen several recently with failed fuel pump relays.


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Thanks for the responses.

I got a code reader and it's giving me P0171 and P0174, which means there is a lean fuel air mixture. From what I read it could be a number of things - vacuum leak, fuel pump, filter, or injectors, bad cat, or the Map sensor. Going to check the forum more and ses what I can find. I checked the fuel pump fuse and it was fine.

Please let me know if you have any idea on how to fix this.

Use a test light and check to see if there is power on that fuel pump fuse while someone cranks the engine.


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SLT617 said:

Thanks for the responses.

I got a code reader and it's giving me P0171 and P0174, which means there is a lean fuel air mixture. From what I read it could be a number of things - vacuum leak, fuel pump, filter, or injectors, bad cat, or the Map sensor. Going to check the forum more and ses what I can find. I checked the fuel pump fuse and it was fine.

Please let me know if you have any idea on how to fix this.

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Not trying to be rude here but there is no magic bullet solution. You are going to have to find out what it is not by process of elimination. You may get lucky with the first thing like the fuel pump but the other stuff is going to take some scope and diagnostic work unless you want just shotgun parts at it until you get lucky.

Did you ever get a fix for this problem and what did you do? I have the exact same truck with about 50K miles on it and I am having the exact same issue, any insight would be appreciated, thanks.

It’s been my experience to check to see if the fuel pump is not working is just to turn the key to almost start. If the fuel pump is working you will hear it turn on for a few seconds. Once the pressure builds up, it will shut off.