Fuel Delivery Questions- Thoughts Folks..

[LibertyTC]

My 04 KJ is strange.
After sitting for 10 hours, I turn the key on, I do not hear the pump humm or nothing at all. Should the pump be heard when you first turn the key on?
How long should you hear it for? Been a while since I heard it, now that I think about it.
So whatever, I start it. It starts but kinda stumbles, almost like it is going to stall, but gets going ok within a second or two. Have not had a chance to look at rpm while its getting going in Park. Driveability seems ok once warmed up.

Since a fuel pressure test should be next, I noticed that the FSM states 49.2 psi plus or minus 2 psi.
I believe there is a test port there, so I just screw it in and get a reading, and also once it is running right? Anything I Should know re Psi or other info?

Then onto the external fuel filter, mounted just outside the fuel tank.
Any hints on replacing that? The FSM states that it is serviceable does not look like much fun to get at though.

 

[uss2defiant]

I think I also hear the fuel priming w/ the humming noise.

There's a schrader valve on both fuel rails.
You can look at whether the pressure holds when it is primed and also when the running.

For the fuel filter, I think you'll have to drop the fuel tank unless you have that service port under the carpet in the cargo area.

http://www.jeepkj.com/forum/f202/how-change-fuel-filter-27498/

http://www.jeepkj.com/forum/f202/another-one-how-replace-fuel-filter-46894/

 

[LibertyTC]

I think there is only one schrader valve on passenger side, but will have a look again.
This Saturday going to drive to the shop, and borrow their fuel pressure tester and see where it stands. If it is not around 49psi, the fuel filter or fpr may be suspect.

Also back to fuel pump priming, if I am not hearing the pump run when I turn ignition on, what's up with that?

 

[uss2defiant]

hmmm.... maybe it's primed already?
maybe try removing the fuse to the fuel pump and depressurize the system then put the fuse back on

 

[RenKJ]

I also always hear the fuel pump priming on power up, gona get around to check rail pressures before next winter just as a precaution, just curious, if i found the fuel pressure dropped off only when i gave it some throttle, would that indicate a filyer clog type issue?

 

[LibertyTC]

Tomorrow I get to borrow a good fuel pressure gauge.
There is no schrader valve on the driver's side.
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There is however one..
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In the meantime I need to fill up...
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:gr_grin:

 

[70AnvKK]

Nice 61 Catalina there at the old pump!

 

[LibertyTC]

Fuel rail pressure test complete.
The specification from my FSM states 49.2 psi plus or minus 2 psi.
I got readings as high as 60 psi....but why? :wtf2:
So we look up the specs on all data, there are two reading 49.2 psi for a 2 connector PCM and 59.2 psi for a 4 connector PCM :nutkick:
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I have a 4 pin block, so 60 psi is good.:drink_nl:
In this photo 30 minutes time has passed and is the leak down test, 45 psi observed.
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Next turn the key on, pump does prime, even though I could not hear it cabin, you could hear it with hood open, go figure.
Pressurizes up to 56 psi.
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Start Jeep and it stabilizes to 60 psi.52628[/ATTACH]"]

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So there it is, no fuel pump issues here.:icon_biggrin:
With the stumble in idle at first starting cold, I think my next move is to find a new OEM-IAC and install it.arty52:

 

[MarkJ]

My 2005 has only one port - passenger side as you found. I have NEVER heard my fuel pump. Even when trying to hear it. I just changed my fuel pump module a couple months ago and found mine did not have the trapdoor under the carpet. So I had to drop the tank, and hitch, and skid plate to get it done. Some models (maybe older than 2005) had a fuel filter outside the tank which is replaceable from underneath. On mine the filter is part of that inside tank module.

 

[profdlp]

Good troubleshooting work, TC. :worthy:

 

[uss2defiant]

Will you be ordering the IAC from Avondale wholesale parts?

 

[LibertyTC]

Not sure. I got an account with Chrysler, I get some real deals.
Thanks for mentioning Avondale though, will price compare once I get a price from dealer.
Our Canuck buck is not doing too good right now, add the postage & exchange at 20% =eek

 

[uss2defiant]

postage is 1 cent if I recall but I could be wrong after the finalize the payment process.