Jeep 2012 JK - Hard Starting

flatfender

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Joined
Feb 28, 2015
Location
Wake Forest
All,

I've got a 2012 JKU 3.6L that's been hard to start but starts every time. Usually requires multiple cranks, but then fires up and runs fine. ETC light comes on when it fails. Doesn't seem to be electrical from a battery/starter, etc standpoint. So I'm thinking it's fuel, ETC related but not sure where to start troubleshooting. Any advice or ideas would be great.

Thanks,

Matt P.
 
a_kelley said:
Check fuel pressure before you key on and start.. or, turn the key on, wait 3sec, off, on, wait 3sec and try to start. If it fires up immediately, suspect pump check valve, leaking injector or pressure regulator.

Good luck.
Click to expand...

Ok, this definitely makes it start right up. Now to find out why it’s bleeding pressure off :( She has noticed that it’s more prevalent when hot, which makes sense if metal or rubber is expanding or contracting, etc. Not looking forward to finding the trouble spot :)
 
Well to help you out -

Regulator is pump mounted - fuel pump assembly will include regulator. You only need to determine if the injectors are bleeding pressure or it's going back in the tank. You can do that by attaching a gauge to the fuel line and priming the pump & let it sit.. if the pressure holds for some time (30-60 minutes) & drops 50% MAX at 1 hour, the pump & regulator are ok. If it drops more than 50% in an hour, the pump or regulator is bad. If it holds, suspect a leaky injector. Any misfire on hot long startup?
 
Thanks I was planning on getting a gauge to check what the pressure was doing, but knowing which direction to look is extremely helpful - Thanks!


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Autozone will rent you a very complete fuel pressure kit....I recommend renting with cash so you get your money back right away rather than hoping the clerk processed your credit card refund.
 
It probably is fuel related, but on the off chance that everything checks out, I had a similar issue on my YJ years ago, everything checked great, just a constant hard start / multiple attempts. One day it gave me the click-click of the starter solenoid engaging but not turning. Pulled the starter to find if was full of mud.
 
shelby27604 said:
It probably is fuel related, but on the off chance that everything checks out, I had a similar issue on my YJ years ago, everything checked great, just a constant hard start / multiple attempts. One day it gave me the click-click of the starter solenoid engaging but not turning. Pulled the starter to find if was full of mud.
Click to expand...

I tried a different starter thinking The windings had a flat spot, but same result. I’m pretty sure it’s fuel related as well at this point


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