First Daily Start-up: What the Heck?

JeepLibertyKK · Dec 4, 2024

(I have a 18 second video but no idea if it can be posted here or the process to post if allowed.)

2012 Liberty Sport / 95k miles
I’ve had an ongoing start-up issue since summer. All these years and the Liberty always started up immediately with no drama… and now this. On initial start-up, it just cranks and cranks and the engine doesn’t really want to fire. I turn off the ignition and then redo the ignition start and it will start up. All seems ‘normal’ after this start and for the rest of the day. Battery voltage before start-up and voltage while running are both in normal range. Starter sounds like it’s turning over at normal speed.

Any suggestions on what might be going on and what I should check?

Thank-you
Richard

kiwi_outdoors · Dec 4, 2024

Time to change your plugs

lfhoward · Dec 4, 2024

Sounds very familiar. My 08 KK did that too. The fix was to replace the fuel pump inside the tank. The tank has to be dropped to do that job. Not fun but yes doable in your driveway. No smoking though!

The short term workaround is to turn the key to run for a couple of seconds before trying to start it. This allows the weak fuel pump to build up fuel pressure in the line. This is also the reason your KK starts on the second crank attempt.

JeepLibertyKK · Dec 5, 2024

kiwi_outdoors said:
Time to change your plugs

Thank-you for the reply. I have purchased spark plugs, ignition coils and an ignition wire set for an upcoming tune-up.

JeepLibertyKK · Dec 5, 2024

lfhoward said:
Sounds very familiar. My 08 KK did that too. The fix was to replace the fuel pump inside the tank. The tank has to be dropped to do that job. Not fun but yes doable in your driveway. No smoking though!

The short term workaround is to turn the key to run for a couple of seconds before trying to start it. This allows the weak fuel pump to build up fuel pressure in the line. This is also the reason your KK starts on the second crank attempt.

With a fuel pump issue, would it throw an error codes?
Thank-you.

lfhoward · Dec 5, 2024

JeepLibertyKK said:
With a fuel pump issue, would it throw an error codes?
Thank-you.

No, mine didn't throw error codes because it never got so bad as to cause a lean condition or misfires while at full throttle. It's almost like the heat soak issue on the old XJ's where it is more likely if the engine is hot and you go into the store, come back out in 5-10 minutes, and try to restart. No codes. Just cranks and cranks. What I think is going on with the old fuel pump is the internal seals are failing and fuel is allowed to drain backwards to the tank after you shut it off. This is more likely if the fuel rail is hot and the gas vaporizes in there.

DadOSix · Dec 5, 2024

Easy fuel pump test -

Cold jeep -

Turn key to run - listen for pump. May or may not hear it.

Do this 4-5 times to pressurize the line.

It should start right up if the fuel pressure is bleeding off.

Of course, the correct way is to borrow / rent a fuel pressure gage and test pressure at the rail.

JeepLibertyKK · Dec 8, 2024

DadOSix said:
Easy fuel pump test -

Cold jeep -

Turn key to run - listen for pump. May or may not hear it.

Do this 4-5 times to pressurize the line.

It should start right up if the fuel pressure is bleeding off.

Of course, the correct way is to borrow / rent a fuel pressure gage and test pressure at the rail.

Great idea. I’ll try that tomorrow morning and post the results. Interesting thought on my issue.

JeepLibertyKK · Dec 9, 2024

DadOSix said:
Easy fuel pump test -

Cold jeep -

Turn key to run - listen for pump. May or may not hear it.

Do this 4-5 times to pressurize the line.

It should start right up if the fuel pressure is bleeding off.

Of course, the correct way is to borrow / rent a fuel pressure gage and test pressure at the rail.

Okay, I was able to do this test today. I cycled the ignition five times and then started the engine. It wasn’t a perfectly ‘normal’ start-up like before this issue, but was far better than not doing the ignition cycling test. I’ll probably do the test a few more times, both ‘cycling’ and not cycling the ignition at start-up and see if I can establish a better pattern.

Can an AutoZone or equivalent do a fuel pressure test, or something that needs to be done by an auto mechanic?

Thank-you
Richard

DadOSix · Dec 9, 2024

JeepLibertyKK said:
Okay, I was able to do this test today. I cycled the ignition five times and then started the engine. It wasn’t a perfectly ‘normal’ start-up like before this issue, but was far better than not doing the ignition cycling test. I’ll probably do the test a few more times, both ‘cycling’ and not cycling the ignition at start-up and see if I can establish a better pattern.

Can an AutoZone or equivalent do a fuel pressure test, or something that needs to be done by an auto mechanic?

Thank-you
Richard

AZ should have a loaner tool

https://www.autozone.com/test-scan-and-specialty-tools/fuel-pressure-tester/p/innova-fuel-injection-pressure-tester/273356_0_0?searchText=fuel+pressure+tester

Seems as now, you buy the tool, use it and have 90 days to return it.

I guess that makes sense rather than just loan it, but then again, i never met a tool i did not want to keep!

You can get a tester also at harbor freight if you have one near.

Essentially, there is a fitting on the fuel rail called a schrader valve. (Looks like a fat tire valve) and - key off, cold jeep, you remove the cap from the valve and thread your tool onto that. Maybe a little spray of fuel.

Then - turn the key on and leave it just ‘on’ not start and walk round and read the pressure. Note it. Key off and walk away for a bit.(5 minutes to an hour) and see if that same pressure holds. I will wager it does not hold and you have diagnosed a weak fuel pump. If the pressure does hold, then we need to look and see what the pressure should be with key on. I * think * 65 PSI or so. Don’t recall right off. For me, if it is carrying on with hard starts and marginal pressure, i replace the pump (with a decent one - mopar - delco ) so as to not have to do the job again.

JeepLibertyKK · Dec 10, 2024

DadOSix said:
AZ should have a loaner tool

https://www.autozone.com/test-scan-and-specialty-tools/fuel-pressure-tester/p/innova-fuel-injection-pressure-tester/273356_0_0?searchText=fuel+pressure+tester

Seems as now, you buy the tool, use it and have 90 days to return it.

I guess that makes sense rather than just loan it, but then again, i never met a tool i did not want to keep!

You can get a tester also at harbor freight if you have one near.

Essentially, there is a fitting on the fuel rail called a schrader valve. (Looks like a fat tire valve) and - key off, cold jeep, you remove the cap from the valve and thread your tool onto that. Maybe a little spray of fuel.

Then - turn the key on and leave it just ‘on’ not start and walk round and read the pressure. Note it. Key off and walk away for a bit.(5 minutes to an hour) and see if that same pressure holds. I will wager it does not hold and you have diagnosed a weak fuel pump. If the pressure does hold, then we need to look and see what the pressure should be with key on. I * think * 65 PSI or so. Don’t recall right off. For me, if it is carrying on with hard starts and marginal pressure, i replace the pump (with a decent one - mopar - delco ) so as to not have to do the job again.

‘Essentially, there is a fitting on the fuel rail called a schrader valve. (Looks like a fat tire valve) and - key off, cold jeep, you remove the cap from the valve and thread your tool onto that. Maybe a little spray of fuel.’

I did another test today (Tuesday) and same result as yesterday. Cycled 5 times, Jeep started, only slightly less smooth than its ‘normal’ days.

I looked and see no valve of any kind on the fuel rail on the passenger side; there is a black hose connected to the fuel rail on the drivers’ side. (********* cap on a line close to the fuel rail is for the A/C.)

The valve IS on the passenger side fuel rail, correct?

DadOSix · Dec 10, 2024

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It should be right below that fitting on the ac hose that you show in your picture. It can be anywhere on that rail. Watch the above video for where it should be located and test procedure

JeepLibertyKK · Dec 10, 2024

DadOSix said:
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It should be right below that fitting on the ac hose that you show in your picture. It can be anywhere on that rail. Watch the above video for where it should be located and test procedure

Thank-you for your continuing help. I certainly can’t explain it but there is no schrader valve anywhere on the passenger-side fuel rail.

DadOSix said:
‘It should be right below that fitting on the ac hose that you show in your picture. It can be anywhere on that rail. Watch the above video for where it should be located and test procedure.’

I watched the video and re-inspected under the hood. I cannot explain it but there is no schrader valve or any other fitting on the passenger-side fuel rail. There is a line that runs to the drivers’ side fuel rail with a hose connected to it and without disassembly, I’m guessing it is not a schrader valve on that side either.

Thank-you
Richard

DadOSix · Dec 10, 2024

Hmm. Without a kK to see, you got me stumped. The line usually runs up the driver side firewall and has a connection like a transmission line. Then the rail runs up the left side of the engine, and has ports for 3 injectors, makes a 90 degree turn to the right and crosses the intake. Then another 90 right and ports for 3 more injectors. The service port is usually on the rail. Maybe Jeep changed things and moved the test port back close to the firewall where the line comes up from the tank.

JeepLibertyKK · Dec 10, 2024

DadOSix said:
Hmm. Without a kK to see, you got me stumped. The line usually runs up the driver side firewall and has a connection like a transmission line. Then the rail runs up the left side of the engine, and has ports for 3 injectors, makes a 90 degree turn to the right and crosses the intake. Then another 90 right and ports for 3 more injectors. The service port is usually on the rail. Maybe Jeep changed things and moved the test port back close to the firewall where the line comes up from the tank.

Your description of the routing seems correct, just no schrader valve on passenger-side fuel rail. Note the fuel rail on the passenger side ends near the firewall.

DadOSix · Dec 10, 2024

JeepLibertyKK said:
Your description of the routing seems correct, just no schrader valve on passenger-side fuel rail. Note the fuel rail on the passenger side ends near the firewall.

Alright then —

Next best idea - we need to get a look at the tester kit and see that it has an adapter that will fit in the fuel line - So i’d be disconnecting that fuel feed line that comes up by the brake booster and fitting the adapter there. So we are bypassing the rail and reading the pressure right there.

It takes , of course, a special fuel line / ac line tool to release that fitting - it’ll push in from the rail side to slide under the metal of the fitting and depress the lock ring that is inside there. Then the test kit adapter must fit in there to allow the gage to connect to the fuel line adapter.

There is a discrepancy in the mopar parts catalog. If you poke in a 12 3.7 liberty, the diagram shows our famous rail with a test port. Drilling further into the photo of the part, the port is no longer seen.
Mopar must have saved 50 cents per rail by eliminating the port.

DadOSix · Dec 10, 2024

Mopar OEM 6539A 5/16" Fuel Pressure Test Adapter - Tillman Tools

This 5/16" adapter is used with C-4799 gauge & hose assembly for fuel pressure diagnostics on vehicles equipped with metal fuel rails.

tillmantools.com

See this gizmo? Imagine the line and black fitting separated. This is the thing that you insert at the fuel feed to the rail, and can then measure static pressure, running pressure and pressure drop.

With as expensive as we are getting with the tooling, it may make more sense to have your local mechanic test those pressures for you.

JeepLibertyKK · Dec 11, 2024

)

DadOSix said:
Mopar OEM 6539A 5/16" Fuel Pressure Test Adapter - Tillman Tools

This 5/16" adapter is used with C-4799 gauge & hose assembly for fuel pressure diagnostics on vehicles equipped with metal fuel rails.

tillmantools.com

See this gizmo? Imagine the line and black fitting separated. This is the thing that you insert at the fuel feed to the rail, and can then measure static pressure, running pressure and pressure drop.

DadOSix said:
Thank-you very much for all your help and advice.

Richard

DadOSix said:
Mopar OEM 6539A 5/16" Fuel Pressure Test Adapter - Tillman Tools

This 5/16" adapter is used with C-4799 gauge & hose assembly for fuel pressure diagnostics on vehicles equipped with metal fuel rails.

tillmantools.com

See this gizmo? Imagine the line and black fitting separated. This is the thing that you insert at the fuel feed to the rail, and can then measure static pressure, running pressure and pressure drop.

With as expensive as we are getting with the tooling, it may make more sense to have your local mechanic test those pressures for you.

Nice work on finding a solution for Liberty’s without the schrader valve on the fuel rail. No idea why mine doesn’t have it; maybe a running-production change to save Jeep three cents. Based on its age, I’m not sure how much longer I want to spend money on this vehicle, but my wife loves it so we’ve kept it longer than maybe we should have. Just today, it threw a new error code which I don’t know if it ties into this starting issue: ‘P0116 / Engine Coolant Temperature Sensor.’ Guess I’ll start yet another thread!

Thank-you for all your help and advice. If I get a shop involved, I’ll post the outcome.
Richard

DadOSix · Dec 11, 2024

JeepLibertyKK said:
)

Richard

Nice work on finding a solution for Liberty’s without the schrader valve on the fuel rail. No idea why mine doesn’t have it; maybe a running-production change to save Jeep three cents. Based on its age, I’m not sure how much longer I want to spend money on this vehicle, but my wife loves it so we’ve kept it longer than maybe we should have. Just today, it threw a new error code which I don’t know if it ties into this starting issue: ‘P0116 / Engine Coolant Temperature Sensor.’ Guess I’ll start yet another thread!

Thank-you for all your help and advice. If I get a shop involved, I’ll post the outcome.
Richard

You are welcome!

Final thought on the adapter - If you are near to a junkyard that has some kj or kk jeeps, pull a rail and the associated line from back near the brake booster. You now have what you need to fabricate your own adapter with a few bits of compression / flare fittings.

Hope you get it sorted.

First Daily Start-up: What the Heck?

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