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Re: OT, Jeep Liberty Misfire Problem
Posted by: gnvair ()
Date: April 15, 2018 04:47AM

streblerm Wrote:
-------------------------------------------------------
> You might check out the MAF (mass air flow sensor)
> They make a special cleaner for them but I have
> used brake cleaner successfully. They are usually
> two little heated wires shrouded in a small bulb
> exposed to airflow in the air intake. If they are
> dirty they tell the computer that less air is
> getting to the engine which cuts the fuel trim as
> well. Eventually the o2 sensor takes over and
> evens out the fuel mix.
>
> If the wires in the MAF aren’t bright and shiny
> then it won’t read correctly. Pull the sensor,
> spray it and wait a few seconds then spray again.

Chrysler doesn't use mass air flow sensors of Jeep Libertys

Lee J

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Re: OT, Jeep Liberty Misfire Problem
Posted by: moomba32 ()
Date: May 12, 2018 08:07AM

Wow this thing has been running like this for a month, still driving it. I have eliminated bad gas of course, throttle position sensor, ADS relay and cleaned the throttle body. I've looked for vacuum leaks, still haven't found any. I have determined through driving that it's not related to engine RPM, just is easier to deal with at higher RPM. It seems to be more associated to intake manifold pressure. Under harder acceleration it runs fine, it actually only skips when it's driving at steady speed. I can give it just enough throttle for it to either slowly accelerate or decelerate and it runs good, it's that small area in between that it runs rough. Another symptom is under a normal acceleration up to 55 about the time it reaches 45 it quickly shifts into OD and locks the converter, the RPMs fall and it starts bucking like a standard shift in too high of a gear. I'm guessing MAP sensor right now, any thoughts? What tells it when to shift?

Don Marlowe
66 Monza 2Dr 140/pg
64 Spyder convertible now, 110/pg
Eutawville SC

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Re: OT, Jeep Liberty Misfire Problem
Posted by: jjohnsonjo ()
Date: May 13, 2018 05:52AM

Did you install new wires when you changed the plugs?

J.O.

65 Corsa Turbo Vert
79 Honda XL 500S
69 Honda CL 160 D
2010 BMW F 650 GS
2003 Bounder 36D
2013 KIA Optima SX turbo-AKA ZIPPY (wife,s car)
69 Newport Holiday Sailboat
Baja 150 dune buggy cart
Coleman HS 500 UTV
2016 KIA Sorento SXL Turbo

Bethlehem,Pa

Image and video hosting by TinyPic

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Re: OT, Jeep Liberty Misfire Problem
Posted by: gnvair ()
Date: May 13, 2018 06:14AM

Have you had any compression or leak down testing performed? Is the P0300 code returning after clearing it?

Lee J



Edited 1 time(s). Last edit at 05/13/2018 06:18AM by gnvair.

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Re: OT, Jeep Liberty Misfire Problem
Posted by: chris ()
Date: May 13, 2018 07:43AM

Lee makes a good point about the code returning. I'm still wondering about the ignition. These systems are hopefully more reliable than GM's coil packs were but the symptoms sound the same as those I had on my Cutlass and Grand Prix.

'65 Monza 4 door
4 speed
110hp
Gardner, KS

Heart of America Corvair Owners Association

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Re: OT, Jeep Liberty Misfire Problem
Posted by: Brizo ()
Date: May 13, 2018 08:30AM

moomba32 Wrote:
-------------------------------------------------------
> Wow this thing has been running like this for a
> month, still driving it. I have eliminated bad gas
> of course, throttle position sensor, ADS relay and
> cleaned the throttle body. I've looked for vacuum
> leaks, still haven't found any. I have determined
> through driving that it's not related to engine
> RPM, just is easier to deal with at higher RPM. It
> seems to be more associated to intake manifold
> pressure. Under harder acceleration it runs fine,
> it actually only skips when it's driving at steady
> speed. I can give it just enough throttle for it
> to either slowly accelerate or decelerate and it
> runs good, it's that small area in between that it
> runs rough. Another symptom is under a normal
> acceleration up to 55 about the time it reaches 45
> it quickly shifts into OD and locks the converter,
> the RPMs fall and it starts bucking like a
> standard shift in too high of a gear. I'm guessing
> MAP sensor right now, any thoughts? What tells it
> when to shift?

Moomba, Believe it or not, light accelerating at 40-45mph.in OD and lock-up is the heaviest you can load that engine. You cant brake torque it standing still - the computer wont let you. If you floor it at speed - it down shifts. And with so many gear ratios to choose from you cant "lug it". The higher the cylinder pressure (40-45) the more voltage is required to fire the plug and everything about your description sounds like you have a secondary ignition part that is shorting internally or to ground at that point.

Dan Brizendine,
'64 8door Greenbrier 140 PG. "In beautiful Wanamaker Indiana...with one stop light and 5 pizza shops"



Edited 1 time(s). Last edit at 05/13/2018 08:32AM by Brizo.

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Re: OT, Jeep Liberty Misfire Problem
Posted by: moomba32 ()
Date: May 13, 2018 03:22PM

Dan,, sounds like you know way more about it than I. Any suggestions on which parts to start replacing? Bear in mind it was running the same with old plugs with a gap of at least 120 thousandths before I installed new plugs with the correct gap. I would think it would take a higher voltage to jump the worn gap but changing the plugs had no effect.
I will try and get a new read on the codes.

Don Marlowe
66 Monza 2Dr 140/pg
64 Spyder convertible now, 110/pg
Eutawville SC

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Re: OT, Jeep Liberty Misfire Problem
Posted by: gnvair ()
Date: May 13, 2018 04:07PM

See if you can get a hold of a scan tool and watch the misfire counter to see if you can catch which cylinder (or cylinders) are misfiring.

Lee J

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Re: OT, Jeep Liberty Misfire Problem
Posted by: Brizo ()
Date: May 13, 2018 04:53PM

moomba32 Wrote:
-------------------------------------------------------
> Dan,, sounds like you know way more about it than
> I. Any suggestions on which parts to start
> replacing? Bear in mind it was running the same
> with old plugs with a gap of at least 120
> thousandths before I installed new plugs with the
> correct gap. I would think it would take a higher
> voltage to jump the worn gap but changing the
> plugs had no effect.
> I will try and get a new read on the codes.

Moomba, Plug gaps of .120 would require the firing voltage to rise to nearly triple what is normal to jump the gap. That placed a real strain on all the insulating materials so I'd be suspecting a bad coil or plug wire. Yes, find a scanner with misfire counting AND history and it may show you exactly which cylinder is misfiring during a test drive.

Dan Brizendine,
'64 8door Greenbrier 140 PG. "In beautiful Wanamaker Indiana...with one stop light and 5 pizza shops"

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Re: OT, Jeep Liberty Misfire Problem
Posted by: jjohnsonjo ()
Date: May 13, 2018 05:05PM

I will just add that "exactly" what you are describing happened to my motor home with a 8.1 Chevy. I changed the plugs and wires on the road in an RV park. Two of the iridium plugs opened to .090. New plugs and wires and I was on the road with no more miss.

J.O.

65 Corsa Turbo Vert
79 Honda XL 500S
69 Honda CL 160 D
2010 BMW F 650 GS
2003 Bounder 36D
2013 KIA Optima SX turbo-AKA ZIPPY (wife,s car)
69 Newport Holiday Sailboat
Baja 150 dune buggy cart
Coleman HS 500 UTV
2016 KIA Sorento SXL Turbo

Bethlehem,Pa

Image and video hosting by TinyPic

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Re: OT, Jeep Liberty Misfire Problem
Posted by: moomba32 ()
Date: May 13, 2018 06:43PM

Well it doesn't really have plug wires, coil plugs onto the plug. I went ahead and bought six new Mopar coils for it, that should fix it or eliminate those. Thanks for the help. There are a few ways this can end up. I'll drive it forever running weird, I'll fix it, or I'll pay someone to fix it. Mostly I'm short on time, the coils are cheap enough and I can install them all in about 15 minutes. Will let you know, may be a couple weeks.

Don Marlowe
66 Monza 2Dr 140/pg
64 Spyder convertible now, 110/pg
Eutawville SC

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Re: OT, Jeep Liberty Misfire Problem
Posted by: cnicol ()
Date: May 13, 2018 08:13PM

Best to fix an ignition misfire rather than "live with it". A long-term misfire will wash the cylinder of oil and it goes downhill from there.

Craig N. Coeur d'Alene ID.
66 Black Monza 4dr, 4.2L V8 49k
61 Seamist Jade Rampside 140 PG
60 Monza coupe (sold, sniff sniff)
66 Sprint Corsa convt - First car! Re-purchased 43 years later
2+2 gnatsuM 5691

+17 Tons of parts

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Re: OT, Jeep Liberty Misfire Problem
Posted by: moomba32 ()
Date: May 16, 2018 05:57AM

Codes update.
P0300. Random misfire
P0441 Evaporative emissions leak, gas cap.
P0522 Oil pressure, sender is bad.
P0131 O2 Sensor Bank 2, Number 1
P0132 Same as 131
P0123 Throttle Position Sensor, from when I swapped it, connector was loose.

Would O2 sensor cause the problem or my thinking is that the problem has caused the O2 code.

Don Marlowe
66 Monza 2Dr 140/pg
64 Spyder convertible now, 110/pg
Eutawville SC

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Re: OT, Jeep Liberty Misfire Problem
Posted by: jjohnsonjo ()
Date: May 16, 2018 06:07AM

Not related to you issue Don, but I was fighting an evaporative emissions leak on my wife's car for a couple of months. Then one day it needed gas and I had more free time to fill it than her. When I went to fill it I found the gas cap was very loose. When I ask her about it she had been leaving it loose for a couple of months because it was much easier for her to open. Tightened it down and end of problem.

J.O.

65 Corsa Turbo Vert
79 Honda XL 500S
69 Honda CL 160 D
2010 BMW F 650 GS
2003 Bounder 36D
2013 KIA Optima SX turbo-AKA ZIPPY (wife,s car)
69 Newport Holiday Sailboat
Baja 150 dune buggy cart
Coleman HS 500 UTV
2016 KIA Sorento SXL Turbo

Bethlehem,Pa

Image and video hosting by TinyPic

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Re: OT, Jeep Liberty Misfire Problem
Posted by: bwells ()
Date: May 16, 2018 06:34AM

Folks,

I have seen similar issues on a couple of newer vehicles. Problems that pop up right after filling up are sometimes related to the evaporative emissions control system. There is a complicated system that seeks to minimize the release of gas vapors to the atmosphere. If you try to top off the tank to the last drop, it overloads the canister for storage, fills lines with raw gas and creates a very rich mixture in the engine. This can also be an indicator of a bad or weak purge valve that controls when the vapors are allowed into the intake. Usually, OBD random and cylinder specific misfire codes show up.
Bottom line- don't overfill your newer vehicle at the gas station, especially european vehicles.

Good Luck,
Bill

Bill Wells
North Texas Corvair Assoc.
www.northtexascorvair.org
61 Ramp
65 Corsa

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Re: OT, Jeep Liberty Misfire Problem
Posted by: glivorsi ()
Date: May 16, 2018 10:43AM

Let us know how she runs with the new coils.

My Mazda would get a constant check engine light for the canister purge valve. After 3 purge valves under warranty, the dealer replaced the vacuum test pump and all the vent plumbing to the gas tank, did a smoke test on the entire system, and replaced the gas gap. I also had a data recorder plugged into my OBDII connector for about 2 weeks. After about 10 trips they finally kept the car for a week or so and had some guru from Japan looking at it. While they had a bunch of monitors hooked up to the engine, the PCM momentarily dropped power to the purge valve. PCM's monitor the voltage return from a sensor, and since it didn't see a return voltage the PCM assumes that the component is bad and it trips a code. They replaced the PCM in the car and I never had another problem with it.

Greg in Wildwood, MO (part of the St. Louis urban sprawl)

1965 Monza Vert 110PG, Crocus Yellow with black interior and top

2014 Honda Accord V6 (DD)
2017 Honda Pilot (wifemobile)
2012 Chevy Sonic 1.8L (kid's car)
1997 Honda CBR1100XX
2006 Mazdaspeed 6 (no longer own)

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Re: OT, Jeep Liberty Misfire Problem
Posted by: moomba32 ()
Date: May 20, 2018 07:51AM

6 new coils installed, no change. Anyone know what the sensor installed directly in front of the MAP sensor is? My best guess for next is the MAP sensor. Any other suggestions.

Don Marlowe
66 Monza 2Dr 140/pg
64 Spyder convertible now, 110/pg
Eutawville SC

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Re: OT, Jeep Liberty Misfire Problem
Posted by: Brizo ()
Date: May 21, 2018 02:58PM

I'm not familier with Jeeps but on an '04, it may be an intake air temp sensor.

Dan Brizendine,
'64 8door Greenbrier 140 PG. "In beautiful Wanamaker Indiana...with one stop light and 5 pizza shops"

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Re: OT, Jeep Liberty Misfire Problem
Posted by: moomba32 ()
Date: May 21, 2018 04:22PM

OK, new clue. I was watching a video on a Jeep skipping, the tech unplugged each coil while it was running looking for a change in idle, looked easy enough so I tried it. Well the first three I unplugged made virtually no difference, all on the left, drivers, bank, I only pulled one on the right bank and had a very noticeable change, others are a bit more work to access and was short on time. So this is making me think there's something effecting that one side and not the other? There's one fuel line coming in and the two rails are tied together. I was thinking a burnt intake valve could do this maybe? But I would expect something mechanical would stay broken and this happens all over the RPM range but only at steady speed.
Dan there's one of those currently in my cart, was looking at buying that, a MAP and PCV, all fairly cheap and look easy to change.

Don Marlowe
66 Monza 2Dr 140/pg
64 Spyder convertible now, 110/pg
Eutawville SC

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Re: OT, Jeep Liberty Misfire Problem
Posted by: glivorsi ()
Date: May 22, 2018 09:42AM

The Manifold Air Pressure (MAP) should be between the engine and the throttle. There's also an Intake Air Temperature (IAT) sensor typically in the airbox. The other one would be the Mass AirFlow (MAF) that's usually between the air filter and the throttlebody. These can cause some misfiring when they get dirty, but it's usually at lower RPM. Still, it's easy enough to remove and spray them off with MAF cleaner if you haven't already.

I feel horrible for everything you've gone through troubleshooting this thing. I think I'd either have no hair or gray hair by now!

Greg in Wildwood, MO (part of the St. Louis urban sprawl)

1965 Monza Vert 110PG, Crocus Yellow with black interior and top

2014 Honda Accord V6 (DD)
2017 Honda Pilot (wifemobile)
2012 Chevy Sonic 1.8L (kid's car)
1997 Honda CBR1100XX
2006 Mazdaspeed 6 (no longer own)

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