2009 intermittent - crank but no start

Discussion in 'KK General Discussion' started by DarkPassenger, Feb 22, 2017.

  1. DarkPassenger

    DarkPassenger New Member

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    Hello Everyone,

    Vehicle info: 2009 Jeep Liberty Sport (3.7l, 4x4)

    First post here but I am a long time lurker. Within the past 4 months, our 2009 has developed a "crank but no start issue". To describe what is going on.... it cranks up fine first thing in the morning. However, if I drive for more than 15 minutes, turn it off, and try to start it again.... the engine just cranks over. It will continue to crank over for about 10 seconds then the starter will disengage (tip start feature). Typically, if you wait about 10 minutes, it will then start up with no problem. It is just a bit irritating that if I am running errands and need to run into the store real quick, I then have to sit there for 10 minutes before it will start again. No CEL codes are being thrown, it just doesn't start if the engine is hot. At first, this issue was intermittent but has become increasingly more present. The time it takes before it will restart has also gotten longer. Last week, my wife was stranded for 35 minutes before the jeep would start up again.

    So, here is what has been done so far..... At first, I thought maybe the starter solenoid had gone bad and was just getting hung up while cranking. That is when I learned about the "Tip Start" feature on Chryslers and ruled out this possibility. It's not an issue of the starter not disengaging, the engine just doesn't want to fire up after it has been run for 15+ minutes. The problem is so intermittent that I have not been able to make it surface while I have it in my garage will all diagnostic tools ready to go (figures). All coils are operating correctly, plugs are new, and wiring has been checked for breaks/chaffing. I did notice that the fuel pump was not engaging to prime the system (key on/ engine off). I figured that must be the culprit and replaced the fuel pump last week. However, the problem surfaced again the next day! Fuel pressure is all within specs so on to the next possibility.....

    Crank sensor and cam sensor are all operating within voltage specs. There are no issues once the jeep is running, just when you try to restart after the engine is hot (okay, I have said that enough times). All fuses and relays have been checked (even replaced the relays to be sure).

    Now, I am at the point that I need to narrow down what exactly the issue is before I start throwing more parts at it. I've read/seen on other pages that the cam and crank sensor caused issues like this but it seemed like it caused performance issues while the engine is running. Our engine has never died on us while driving, just doesn't start back up. I've had the jeep hooked up to MODIS and absolutely nothing indicates there being an electrical problem. All sensors are within specs and no codes have ever been thrown. This situation really has me stumped. I've tried multiple keys and continue to have the same results.

    Anyone have a recommendation? I am leaning towards swapping out the cam and crank sensors just to be sure since they are inexpensive. However, I would like to narrow this down and not spend money on parts that won't correct the issue. Thanks for your time.
     
  2. DarkPassenger

    DarkPassenger New Member

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    I will continue to update this thread as I progress through this issue. I keep finding a lot of other threads/sites where people have experienced this same problem. However, it seems that nobody ever comes back to update whether the problem was fixed and what they did to fix it!

    Today, I went out to run some errands, got the engine up to operating temp, and it wouldn't start when I came out from the store. I read up on a few posts last night that this could be a vapor lock issue. Mind you, I was under the impression that vapor lock kind of phased out with the abandonment of mechanically driven fuel pumps.... However, I do see that the fuel rail is very close to the exhaust so who knows? When it wouldn't start today, I held the gas pedal all the way to the floor (I read a post that this shuts off the injectors if the pedal is fully depressed when turning the ignition?). And what do you know..... the engine started after a few cranks. I will try this again next time it doesn't start to see if it works or if that was just a fluke. If it does work, I will be wrapping the fuel rail in heat resistant insulation to see if it helps. It just really has me stumped because the issue just surfaced a few months ago and we have had this Jeep for over 2 years. Perhaps the gas station we use switched to a higher ethanol mix and the boiling point is lower than it used to be?
     
  3. DarkPassenger

    DarkPassenger New Member

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    Update #2 - The fuel in the jeep was nearly empty after the last time the issue surfaced. I checked at my usual fill up spot and sure enough, they had switched to a higher ethanol fuel around the time my jeep started acting up. I found another gas station with a lower mix and filled up with premium. The issue has not happened since then...... I wish that I had thought of the simple things before replacing a bunch of crap that probably didn't need it lol