2012 1500 Cranks but won't consistently turn over and is getting worse (seems to start better on hotter days)

ocifferdave

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A month ago my truck started having issues with remote start. It might turn on, or it might try, sounds like it started, then turn off after 2 seconds of the engine struggling. Turning it on manually via key turn would work with a little bit of struggle (you could hear the engine attempting to turn over, but almost stall out but then run fine).

I had noticed on hotter days it would start up with less struggle.

Lately, its been hit or miss if I can even turn it on via key turn (I don't try the remote start anymore since that keeps failing now).

No engine codes.
No work done on the truck since I got it two years ago (besides the standard oil changes).
Thinking this might be a dirty fuel line issue, I put in the highest grade gas into a near-empty gas tank a week ago along with a fuel line cleaner additive -- no difference, still getting harder to start.

Last two days I cannot start the truck.

Here's a short video of me trying to start the truck today:

https://youtu.be/Z1IKamNSjdU

It's hard to hear, but you can hear the engine starting to turn on then fail. After the second attempt you hear for a split second the engine trying to turn over, but then afterwards its only the sound of the ignition cranking. I even trying pumping the gas peddle (something I have not tried to do before the video today), but that didn't seem to make a difference.

Ideas of what I can try next?

P.S. Letting it roll down a hill in neutral while the engine is off with the key turned to the on position and then throwing it into drive doesn't do a thing.

10/2 UPDATE: Because of this forum I was able to fix my own truck for only $46 and avoid a potential $1300 auto shop bill. Thank you very much!

The Fix: https://www.verticalvisions.com/tipm-test-bypass-cable-mini-blade-fuses.html
 
Last edited:

XCELLR8

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Fuel pump relay
WIN Unit

Are two places to start. You need to find out if it is getting fuel or spark, that will tell you where to go.
 

csuder99

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Sounds like no fuel, check fuel pressure at the rail. It might be the fuel pump relay but not very likely. You can just swap the relay with another non-essential one (e.g. horn) and see if it makes a difference. More likely the fuel pump.
 

SYKRAMMAN

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P.S. Letting it roll down a hill in neutral while the engine is off with the key turned to the on position and then throwing it into drive doesn't do a thing..
That trick only works with manual trany's. Auto trans work off of high pressure.
 

CamperMike

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Csuder, Fuel pump relay is in the TIPM and is troublesome on Mopar vehicles from that time. I don't think it happens as often with these trucks as other models but it still happens. I would bypass the relay and see if it starts better.
 

csuder99

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CamperMike, you're right. The run/start relay is conventional but the fuel pump relay is integrated. Doh !
OP: To check if the fuel pump gets power check if there is 12V at fuse 70 in the PDC during cranking.
 

ocifferdave

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Csuder, Fuel pump relay is in the TIPM and is troublesome on Mopar vehicles from that time. I don't think it happens as often with these trucks as other models but it still happens. I would bypass the relay and see if it starts better.
This was the issue, @CamperMike. Thank for saving me a lot of money and headache by pointing me to what turned out to be the issue.
 

ocifferdave

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CamperMike, you're right. The run/start relay is conventional but the fuel pump relay is integrated. Doh !
OP: To check if the fuel pump gets power check if there is 12V at fuse 70 in the PDC during cranking.
Yep, CamperMike is my hero -- that was the issue and it only cost me $46 to fix it:

 

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