Warm re-starting issues

toy4everyseason · **Posted:** Thu Mar 19, 2015 8:41 pm

So I know mine still has an issue but it hasn't been warm enough to get it to fail for a consistent amount of time for me to hook up the fuel gauge and get a reading. It did it to me today but fired up on the 2nd try. I need temperatures in the 70's, traffic, and a heat soak time of 10min :banghead:

Any less than 10 min or more than 30 min, it doesn't fail consistently.

Gageraid · **Posted:** Fri Mar 20, 2015 10:49 am

toy4everyseason wrote:

So I know mine still has an issue but it hasn't been warm enough to get it to fail for a consistent amount of time for me to hook up the fuel gauge and get a reading. It did it to me today but fired up on the 2nd try. I need temperatures in the 70's, traffic, and a heat soak time of 10min :banghead:

Any less than 10 min or more than 30 min, it doesn't fail consistently.

Are you sure it's not the starter?

toy4everyseason · **Posted:** Fri Mar 20, 2015 10:35 pm

Not 100% sure it isn't the starter but it still cranks just as fast as when it does start. I tried again to make it fail but no luck. I did notice that when its warm & you shut it down pressure falls from 54psi to 34psi in about 10 min. I'll try again tomorrow to verify those results & eliminate the chance I just didn't screw the fuel pressure gauge snugly on the rail. I did find if I pull the fuel pump fuse or ASD relay I can recreate the crank no start issue but that was to expected. I was under there pulling relays to see which ones would kill the fuel.

Scar0 · **Posted:** Sat Mar 21, 2015 7:14 am

Fuel pressure should be 58 psi +/- 5 psi.
If you have a bleed down fuel pressure issue you can check this by doing a key "on" but do not start (listen for the fuel pump), Key "off", key "on" but do not start (listen for the fuel pump again), key off, then try to start it.

Alternately you can do a leak down test. (Compiled from the SM)
Start the rig and let the fuel pressure build to Max, and engine at operating temp.
Turn the ignition off.
Bleed down the fuel pressure by removing the fuel pump fuse.
Try to start the rig until it no longer starts.
Install special tool #6539 (5/16") or #6631 (3/8") fuel line adapter.
Install the fuel pressure gauge.
Start the rig and let the fuel pressure build to Max.
Turn the ignition off.
Fuel pressure should be 58 psi +/- 5 psi.
Using special tool C4390 (Hose Clamp Pliers) pinch the rubber fuel line between the fuel pressure gauge and the engine. (This eliminates a leaky injector affecting the results.)
Monitor the fuel pressure gauge for a minimum of 5 minutes.
The pressure should not fall below 35 psi.
Does the fuel pressure drop?
If yes, replace the fuel pump.

You should also consider the MAP sensor as it tells the PCM what altitude you are at. The PCM uses this info to control the pulse width of the injectors (how much fuel to inject).
It gets pretty deep with the language in the SM, but part of it says; Any time the PCM sees Wide Open Throttle, and RPMs, it will update barometric pressure in the MAP memory cell.
Maybe you just need to run it at WOT so the "pressure" can be updated.

pshivers · **Posted:** Sat Mar 21, 2015 8:52 am

On a side note, I believe MAP barometric pressure is set at key on right before the engine starts. It may update as you say, but unless you're driving through the mountains, it shouldn't change much.

toy4everyseason · **Posted:** Sat Mar 21, 2015 9:57 am

Scar0 wrote:

Fuel pressure should be 58 psi +/- 5 psi.
If you have a bleed down fuel pressure issue you can check this by doing a key "on" but do not start (listen for the fuel pump), Key "off", key "on" but do not start (listen for the fuel pump again), key off, then try to start it.

Alternately you can do a leak down test. (Compiled from the SM)
Start the rig and let the fuel pressure build to Max, and engine at operating temp.
Turn the ignition off.
Bleed down the fuel pressure by removing the fuel pump fuse.
Try to start the rig until it no longer starts.
Install special tool #6539 (5/16") or #6631 (3/8") fuel line adapter.
Install the fuel pressure gauge.
Start the rig and let the fuel pressure build to Max.
Turn the ignition off.
Fuel pressure should be 58 psi +/- 5 psi.
Using special tool C4390 (Hose Clamp Pliers) pinch the rubber fuel line between the fuel pressure gauge and the engine. (This eliminates a leaky injector affecting the results.)
Monitor the fuel pressure gauge for a minimum of 5 minutes.
The pressure should not fall below 35 psi.
Does the fuel pressure drop?
If yes, replace the fuel pump.

You should also consider the MAP sensor as it tells the PCM what altitude you are at. The PCM uses this info to control the pulse width of the injectors (how much fuel to inject).
It gets pretty deep with the language in the SM, but part of it says; Any time the PCM sees Wide Open Throttle, and RPMs, it will update barometric pressure in the MAP memory cell.
Maybe you just need to run it at WOT so the "pressure" can be updated.

Yeah I tried the key trick while it was failing and it still wouldn't start. I tried to replicate the leak down results I got yesterday but of course the Jeep doesn't want to cooperate :banghead:

It only lost 5psi in the same 10min timespan.

Am I also reading correctly that the proper timespan for the leak down test is just 5min? I'm an .....aggressive? driver so my jeep gets plenty of WOT :SOMBRERO:

Scar0 · **Posted:** Sat Mar 21, 2015 11:24 am

The leak down test is a minimum of 5 minutes. But it does not state a Max time.
There are a couple of KA with the same issue.
One replaced a crank sensor and it fixed it for about 4 weeks. Then they never came back to say if they ever figured out the cause.
Wish we could figure it out for everyone...

toy4everyseason · **Posted:** Sat Mar 21, 2015 9:15 pm

Gotcha, I'll have to measure my fuel line & order the correct specialty tool in line tester so I can isolate the fuel pump. I've been taking the measurement at the passenger side of the fuel rail but that doesn't really isolate whether its a fuel pump or leaky injectors. Thanks Scar0 for bringing that to my attention :rockon:

Marlon_JBT · **Posted:** Sat Mar 21, 2015 10:45 pm

It's not fuel. It's not sensors.

Wanna know what I think it is?

A SKREEM or TIPM problem.

Marlon_JBT · **Posted:** Sat Mar 21, 2015 11:42 pm

Guess what just happened to me?

Toy4everyseason, and everyone else who has this issue, do you have the security alarm?

toy4everyseason · **Posted:** Sun Mar 22, 2015 6:02 pm

Nope, no alarm here.

Gageraid · **Posted:** Sun Mar 22, 2015 7:17 pm

Just to route out everything, have you tried other keys yet?

toy4everyseason · **Posted:** Sun Mar 22, 2015 10:01 pm

Gageraid wrote:

Just to route out everything, have you tried other keys yet?

Yep & remote start & even took the time to completely remove the remote start from the car...no change

Gageraid · **Posted:** Sun Mar 22, 2015 10:13 pm

I see you have the 2008.
Is this the original gas tank and parts, or have you have the fuel spit back parts swapped out?
Not sure if this matters, just trying to gather all information.

toy4everyseason · **Posted:** Sun Mar 22, 2015 10:15 pm

Gas tank & filler neck have already been replaced almost 2 yrs ago under the x46 lifetime warranty

Gageraid · **Posted:** Sun Mar 22, 2015 10:17 pm

Is your EVAP canister in good working condition?

Marlon_JBT · **Posted:** Mon Mar 23, 2015 2:24 am

The reason why I was asking, there is a TSB for 2010s that supposedly cures a no start condition. Sometimes these TSBs apply to more than one model year or build date. My Jeep wasn't part of the rear window leak TSB, BUT once it was performed, I had no more leaks.

toy4everyseason · **Posted:** Mon Mar 23, 2015 3:05 am

Marlon_JBT good find, there's information in that TSB that may be very useful in finding a solution. Mostly that if it's failing, to pull the IOD fuse, wait 10 seconds & put it back. If it starts then it may be an electronic lock up of the Wireless Control Module(WCM) aka Sentry Key Remote Entry Module (SKREEM). The only issue I have with that is I've disconnected the battery during a crank no start and it didn't rectify the problem. I wonder how pulling the fuse is any different. I'll have to get in there tomorrow and pull the part number off the WCM to see if it's a defective part as indicated in the TSB 08-007-08 REV. A.

viewtopic.php?f=104&t=39066

toy4everyseason · **Posted:** Mon Mar 23, 2015 7:32 pm

Well my part number for my WCM is 05026071AN which is not the one indicated is a problem on the TSB. I see there is a updated part number for it but the dealership wants almost $300 for parts and labor to install it. I'm not really interested in throwing that much at it to find out later it wasn't the problem... the testing is on going for now since its still not failing consistently. :banghead:

Gageraid · **Posted:** Mon Mar 23, 2015 10:49 pm

I'm gonna throw out there another probably useless question/suggestion.
Does it start up any differently if you try to start it in neutral?

Warm re-starting issues

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