smarks

I have a 2014 Jeep JK Unlimited with ~56K miles. My wife was leaving the house and it died at the end of our driveway. It cranks but will not start. There are no codes. The battery is ~1 month old and is sitting with 12.4V charge. I've pulled battery terminals for reset, as well as replaced the crank position sensor. I can hear the fuel pump pumping up when key is in on position. While i did "throw" a CPS at it, I am not necessarily wanting to throw more parts at it. Any suggestions on what the culprit my be? Cam position sensors? I checked and the codes on my cam position sensors are not the ones impacted by the TSB. Any help would be greatly appreciated...

Thanks in advance,

Spencer

rob_engineer

Oh boy. This identical thing with the same symptoms happened with my 2014 at 58,000 miles. Died after leaving the driveway. No codes. You're not going to like this- it was a broken exhaust spring inside the engine. I posted on here about it back in February. The repair, along with replacing the cracked oil filter housing cost me about $2800. You should check the date when your Jeep was first registered. If within 5 years there's a chance it would be covered if that is your problem.

smarks

I saw your post and was hoping by ignoring it, that wouldn't be my problem. I have approx 57K miles on my Jeep so the similarities are a little uncanny...

Additionally, I just pulled one of my plugs and it is bone dry. I hear fuel pump running momentarily upon turning key to on position so i wasn't thinking it was the fuel pump. I did confirm that there is fuel pressure at the rail.

rob_engineer

Well good luck, and please post back on here once you find the cause and solution.

Sixty4x4

Smarks - not sure if the problem is similar to mine. My 2008, and possibly all others, have a tach pulse that drives the fuel pump after the engine starts. So at key on the pump goes to 60PSI then without the tach pulse during cranking will not turn the pump on again until it sees the tach pulse or unless the key is cycled on/off/on. Even though I have the Chev conversion it was the way the Jeep worked originally and the Motech system simply sent the pulse from the Chev Crank Pos Sensor. Only way to check this is you say you have fuel pressure, but do you have it while cranking? If you don't it will most likely not start. If you do have 55-60 PSI constant during cranking then that is not the problem. Only other thing I could think of is the ignition switch still hot during cranking. Try a downhill start in gear if you have a manual. Note: I will be a long way from anywhere soon on overlanding and fairly good 4WD trips so am going to rig up a 12V bypass direct to the pump to overcome this achilles heel of the Jeep system. My Chev would start, run 10 seconds then die, reset the key and repeat the cycle. Fixed it today.