Won't start after engine is warm

427cobra · **Joined:** Thu Nov 24, 2011 11:02 am **Posts:** 6

Hello,
Hope someone can help me. 2006 Liberty CRD, 60000 miles. Jeep starts most the time when it is cold, then after is has been run around town warmed up and shut off for a little while it will not start. Probem has been getting worse, it was every once and a while, know it is almost everytime. Unplugged heater plug on fuel filter housing and did have a small burn, but shows no sign of fuel coming out ( housing was changed once aproximately 2008) but wires don't look like they were ever spliced or changed so I don't know if burn was from original housing. When I pump fuel housing pump it is soft and takes 5 to 7 pumps before it builds pressure still does not always start, if I let it cool down for a 1/2 to 45 minutes it will usually always start. Sometimes I need to pump fuel housing and sometimes I dont and it will start . When I drive it to work and it sits for 8 to 10 hours before restarting, it starts up. No pressure on the pump makes me believe a leak in the line somewear, but wouldn't happen even when it is cold. Any suggestions on were the most commons fuel line leaks are or should I put pressure pump on it or something else.

papaindigo · **Posted:** Thu Dec 01, 2011 7:24 am

See Sams NOOB guide video on fuel head bleeding, sounds like you are not opening the bleeder screw, for how to and a picture of the 2gen fuel head. A burned fuel heater end makes it virtually certain you have a 1st gen head and even if you see no fuel an air leak; remember our systems "pulls" fuel to the fuel pump so the line is not under pressure hence air going in is easier than fuel going out.

Bottom line is your problem is almost certainly air in the fuel head.

Rich · **Posted:** Thu Dec 01, 2011 10:14 am

My friend Tom (sidebrake) went through one hell of an issue with his CRD and not being able to start with the engine warm. He diagnosed the entire fuel system, spent quite a bit of money, and found it was a stuck injector. You are having the same symptoms with yours...

To prevent others from going through the hell he did, he created the flow chart below for diagnosing fuel system issues.

viewtopic.php?f=5&t=59446&p=661763&hilit=fuel#p661763

Good luck!

papaindigo · **Posted:** Thu Dec 01, 2011 11:38 am

I've seen the chart and it's a good one but given that 427cobra appears to have a 1s gen fuel head with a burn on the heater plug I'd start with installing a new 2n gen head. Minimum is that needs to be done anyway. I can say my air in fuel problem was with a 1s gen head, slight burn on heater plug, and no detectable fuel leak at that plug - problem cured by 2n gen head.

sidebrake · **Posted:** Thu Dec 01, 2011 12:17 pm

Thanks for the plug Rich.

papaindigo - I agree that it's a good idea to replace the fuel head, since he's on the 1st gen unit, if nothing else just as preventative maintenance. It's a (relatively) cheap part and maybe he'll get lucky.

The point of the flow chart is to systematically rule out common problems without spending a ton of money in the process. Because air in fuel is such a common issue, its easy for people to automatically jump to that conclusion, but its not always the right one necessarily. As Rich mentioned, I spent a lot of time and money trying to fix "air in fuel" problems when it was never an issue to begin with.

427cobra - If it is the injector, you're looking at (+/-) $400 plus the cost of flashing the new injector code to the PCM. Other components can cost more (last I checked a CP3 pump was $2k+) so just take your time and do a proper diagnosis so that you're not just throwing money at the problem.

Here's the direct link to the diagnostic: https://docs.google.com/viewer?a=v&pid= ... y=CO3NyM4B

427cobra · **Joined:** Thu Nov 24, 2011 11:02 am **Posts:** 6

Thanks for all the help, going to try recomendaitions this weekend, can anyone tell me what lets it start when engine is cold if air is in the line.
Thanks again

jeepdan · **Posted:** Sun Dec 04, 2011 6:24 am

My cold start problem is evolving into a hot start problem. viewtopic.php?f=5&t=63238&start=20
Yesterday I drove to and from work with lift pump fuse out. The jeep started cold and ran fine. After returning home, I tried restarting after setting for 5 minutes and it would not fire up. I let it set another 8-10 minutes and it fired up instantly. :?:

mozzio · **Joined:** Thu Jan 17, 2008 7:03 pm **Posts:** 59

I have been having this identical problem since I bought my 2005 in 2006. I have replaced the fuel head, added a lift pump form a 3500 dodge ram, replaced two injectors, along with the dealer supposidly cleaning my fuel lines(don't know what that was for) and still have not been able to fix the problem. My jeep has spent almost three years on and off at the local dealer.
I should add that once the engine has been run for 2 or 20 miles I have to wait 2 1/2 hours before it restarts, and then it starts normally. It almost seems like a sensor or something quits working when it's hot.

If you figure this out, please post the solution, or if any one has any other advice for me I am more than receptive to your comments. Thanks in advance!

ATXKJ · **Posted:** Mon Dec 05, 2011 10:55 pm

Well - most of the responses are common CRD issues - however irrespective of CRD's - there are 2 common warm engine issues
1) electrical components that fail when hot but work cold - a friend troubleshot his by taking electronics cold spray and a hair dryer and walking though the ignition (isolated it to a capacitor - which Ford wouldn't sell separately - had to buy a distributor) - slow painful - works.
2) vapor lock - much more of an issue in the summer - not in December - but if your fuel lines are routed close to an exhaust line - it'll still happen - but a lift pump should kill it - pressure is a lot harder to vaporize - vacuum is easy.

(don't expect help from a dealership - maybe a good Cummins/Sprinter diesel mechanic - but not the generic Jeep dealership)

Rich · **Posted:** Tue Dec 06, 2011 12:26 am

Holy hell...

USE THE DIAGNOSTIC TOOL POSTED!

WolverineFW · **Posted:** Tue Dec 06, 2011 5:41 pm

mozzio wrote:

I have been having this identical problem since I bought my 2005 in 2006. I have replaced the fuel head, added a lift pump form a 3500 dodge ram, replaced two injectors, along with the dealer supposidly cleaning my fuel lines(don't know what that was for) and still have not been able to fix the problem. My jeep has spent almost three years on and off at the local dealer.
I should add that once the engine has been run for 2 or 20 miles I have to wait 2 1/2 hours before it restarts, and then it starts normally. It almost seems like a sensor or something quits working when it's hot.

If you figure this out, please post the solution, or if any one has any other advice for me I am more than receptive to your comments. Thanks in advance!

Does it crank and not fire or not crank at all? If it does not crank at all it could possibly be a bad starter solenoid. I had a vehicle with the same problem. Would only start when it was cold because the solenoid was bad.

jeepdan · **Posted:** Tue Dec 06, 2011 5:44 pm

Thanks for the info and charts Rich and sidebrake,
I will perform the Fuel Pressure Soleniod test and Injector leak down test Thursday on my day off.
Hope it is not the Fuel Pressure Soleniod$$$$$$$$$$.
I also thought of switching Cam Shaft Position Sensers with my other CRD to see it is that.
The jeep did just fine yesterday and then today it did not want to restart after stopping at the parts store, took five cranking attempts.
It's still going to be hard to find an intermittent problem, I just wish it would act up at home while it's in the garage :dizzy:

mozzio · **Joined:** Thu Jan 17, 2008 7:03 pm **Posts:** 59

[/quote]Does it crank and not fire or not crank at all? If it does not crank at all it could possibly be a bad starter solenoid. I had a vehicle with the same problem. Would only start when it was cold because the solenoid was bad.[/quote]

Well Rich, the diagnostic chart was helpful but didn't fix the problem.
Jeepdan; It will crank until the battery expires ( i've never done that though) but will only fire after it cools down. It will not refire immediatly after I turn it off either. I have also replaced the mprop and fuel pressure solenoid.

jeepdan · **Posted:** Tue Dec 06, 2011 10:27 pm

mozzio wrote:

Does it crank and not fire or not crank at all? If it does not crank at all it could possibly be a bad starter solenoid. I had a vehicle with the same problem. Would only start when it was cold because the solenoid was bad.[/quote]

Well Rich, the diagnostic chart was helpful but didn't fix the problem.
Jeepdan; It will crank until the battery expires ( i've never done that though) but will only fire after it cools down. It will not refire immediatly after I turn it off either. I have also replaced the mprop and fuel pressure solenoid.[/quote]

That's not very encouraging, I think I will swap Camshaft Position Sensors first, then go for the more involved tests.

jeepdan · **Posted:** Thu Dec 08, 2011 5:05 pm

I was able to do some testing on the jeep today while it was taking one of it's "no start" tantrums with the engine fully warmed up. I placed a piece of clear plastic tubing on the fuel return fitting of the Fuel Pressure Solenoid, disconnected the Camshaft Position Sensor and cranked the engine over. Two five second cranks filled the 5/16 plastic tubing up about 12" in length.
I understand that there shouldn't be any fuel leaking through the Fuel Pressure Solenoid while cranking the engine over to start. How can I determine whether the Fuel Pressure Solenoid is faulty or maybe a faulty Fuel Pressure Sensor is preventing the ECM from holding the Solenoid closed?

jeepdan · **Posted:** Thu Dec 08, 2011 9:12 pm

Just came from the garage, performed the same leak test on the Fuel Pressure Solenoid. This time with the engine COLD, there was not any fuel leakage found in tubing after cranking. Interestingly the engine fired a very short burst with the Camshaft Position Sensor disconnected. :shock:

WolverineFW · **Posted:** Fri Dec 09, 2011 1:28 am

jeepdan wrote:

. How can I determine whether the Fuel Pressure Solenoid is faulty or maybe a faulty Fuel Pressure Sensor is preventing the ECM from holding the Solenoid closed?

Does the solenoid have a part number on it, possibly from Bosch? If so, maybe you can figure out what the normal resistance ratings of the solenoid and then take some readings on yours. If the resistance rises on a soleniod ciruit as it gets old, it tends not to function properly as it cannot get enough amps to pull in/hold in or both.

jeepdan · **Posted:** Fri Dec 09, 2011 5:28 pm

Ordered a new Fuel Pressure Solenoid today. I hate to to throw parts at a problem, but I need this gremlin fixed ASAP and I don't have a Diesel Fuel Diagnostics Manual to double check the wiring circuit. :juggle:

mozzio · **Joined:** Thu Jan 17, 2008 7:03 pm **Posts:** 59

I installed a a new fuel pressure solenoid with no luck. Just replaced the cam sensor. Still won't start when it gets hot

jeepdan · **Posted:** Fri Dec 09, 2011 7:37 pm

mozzio wrote:

I installed a a new fuel pressure solenoid with no luck. Just replaced the cam sensor. Still won't start when it gets hot

Sorry to hear that, was you old Fuel Pressure Solenoid leaking off fuel when cranked hot?

Won't start after engine is warm

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