Cranky Rig

[shellback91 2,305]

I have a question for the group. Occasionally when I start my Jeep it keeps on cranking after I let go of the key. I let go of the key because it is not starting. If I wait a second or two she fires right up.  This usually happens on the first start of the day then it behaves the rest of the time, usually.

 

I was thinking it could be a battery issue, my current AGM battery is about 2 1/2 years old. I am considering replacing it anyway because of the landscape we live in called Phoenix. Thoughts on that are welcome.

 

Back to the crank issue,  the more I think about it I am leaning towards something being stuck. Any thoughts on that? The inter-webs have all kinds of conflicting info so I thought to ask here too.

 

 

-Marty

[Curly 1,317]

First thing that comes to mind is the starter solenoid is sticking.  The internal linkage in the starter gets worn or dirty and it sticks. You may be able to clean it and lube it, but a rebuilt starter is probably a better bet.

 

 

[Curly 1,317]

Here is a diagram of the starter. You can see the shift  lever at the right side of the plunger and the 2 hinge points that wear. If it sticks, it will keep the contacts to the starter motor

connected.

 

 

 

[Bradywgn71 1,008]

On 9/13/2024 at 9:58 AM, shellback91 said:

I have a question for the group. Occasionally when I start my Jeep it keeps on cranking after I let go of the key. I let go of the key because it is not starting. If I wait a second or two she fires right up.  This usually happens on the first start of the day then it behaves the rest of the time, usually.

 

I was thinking it could be a battery issue, my current AGM battery is about 2 1/2 years old. I am considering replacing it anyway because of the landscape we live in called Phoenix. Thoughts on that are welcome.

 

Back to the crank issue,  the more I think about it I am leaning towards something being stuck. Any thoughts on that? The inter-webs have all kinds of conflicting info so I thought to ask here too.

 

 

-Marty

Our XJ was doing this.  For that cranky rig it was not maintaining fuel pressure overnight (or heck even for a few minutes) and had a bad fuel pressure regulator.  The mechanic was able to test it and see the fuel pressure go away almost immediately with key off.  This is of course after us replacing a ton of sensors, computer, fuel pump, etc,

[theksmith 5,778]

did your new battery solve your issue?

 

if not then i have some thoughts for you on this...

[shellback91 2,305]

It may have. I was gone for over a month so it sat until last week. Before I replaced the battery it was behaving itself, it seems to still be behaving. I am in a monitor the situation and consider my options mode now.  Maybe replace the starter just because, I am not sure.

 

Edit: I'll take your suggestions for future reference though.

Edited September 30, 2024 by shellback91

[UselessOverland 20]

On 9/13/2024 at 4:32 PM, Curly said:

First thing that comes to mind is the starter solenoid is sticking.  The internal linkage in the starter gets worn or dirty and it sticks. You may be able to clean it and lube it, but a rebuilt starter is probably a better bet.

 

 

This

[theksmith 5,778]

your starter is probably fine and so is your ignition switch, etc.. i think your only real problem is the intermittent no-start after sitting for a long time...

 

on a JK (3.6L, not sure about 3.8L) the key does not directly control the cranking time, the computer does. you can see what i mean by putting the key in RUN, then just ever so briefly pulse it to START/CRANK - your rig will still crank over till it starts up without you holding the key at START. or could hold the key in the START position long past when it actually starts and yet you won't grind the starter gear because the computer knows when the rig actually fires up and stops powering the starter regardless of the key.

 

your rig is acting normal in terms of trying to crank till it starts even when you let off the key. since you have another issue it eventually does time out and stop cranking though.

 

the no-start after sitting issue is probably your fuel pressure not holding. this can be from a leaky injector, or connector, but most often is a bad fuel pressure regulator. i *think* the regulator on these is in the pump unit inside the tank. :( however, there is a service port on the fuel rail where you can hook up a pressure tester to verify. check a service manual or Google for what the target pressure and realistic time it should hold is. the fact it starts on second try makes sense as it will build up fuel pressure after being on for a few seconds.

 

if it's not a fuel pressure problem, then it could be a sensor such as the intake air temp giving bad readings and so the computer isn't adjusting the fuel/air ratio correctly for that initial start.

 

Edited October 2, 2024 by theksmith

[Curly 1,317]

@theksmith  That was actually my first thought as well, but since he describes a long crank only  on the first start, I discounted fuel psi.  In my experience, if there is a problem with the regulator, then it will be hard start every time (or at least if the vehicle sits for more than 5  minutes).   I've been out of the game too long, I wonder if there is a psi sensor on the JK/JL platform you could read with a  scan tool. 

[shellback91 2,305]

8 hours ago, theksmith said:

your starter is probably fine and so is your ignition switch, etc.. i think your only real problem is the intermittent no-start after sitting for a long time...

 

on a JK (3.6L, not sure about 3.8L) the key does not directly control the cranking time, the computer does. you can see what i mean by putting the key in RUN, then just ever so briefly pulse it to START/CRANK - your rig will still crank over till it starts up without you holding the key at START. or could hold the key in the START position long past when it actually starts and yet you won't grind the starter gear because the computer knows when the rig actually fires up and stops powering the starter regardless of the key.

 

your rig is acting normal in terms of trying to crank till it starts even when you let off the key. since you have another issue it eventually does time out and stop cranking though.

 

the no-start after sitting issue is probably your fuel pressure not holding. this can be from a leaky injector, or connector, but most often is a bad fuel pressure regulator. i *think* the regulator on these is in the pump unit inside the tank. :( however, there is a service port on the fuel rail where you can hook up a pressure tester to verify. check a service manual or Google for what the target pressure and realistic time it should hold is. the fact it starts on second try makes sense as it will build up fuel pressure after being on for a few seconds.

 

if it's not a fuel pressure problem, then it could be a sensor such as the intake air temp giving bad readings and so the computer isn't adjusting the fuel/air ratio correctly for that initial start.

 

 

3 hours ago, Curly said:

@theksmith  That was actually my first thought as well, but since he describes a long crank only  on the first start, I discounted fuel psi.  In my experience, if there is a problem with the regulator, then it will be hard start every time (or at least if the vehicle sits for more than 5  minutes).   I've been out of the game too long, I wonder if there is a psi sensor on the JK/JL platform you could read with a  scan tool. 

 

Thanks gents, After the last few days I am leaning to another issue than the starter too. My gas tank was replaced a couple of years ago, so I am hoping that thing will not need to be dropped.

 

I am going to reach out to Joe and see when I can get in and have him give it a look.