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2006 Jeep Liberty engine vibration  RSS feed
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schwifi

Joined: 12/10/2017 00:00:27
Messages: 3
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I have a 2006 Jeep Liberty crd with a GDE eco tune (full torque). It has 105,000 miles on it and replaced the timing belt at ~90K. The GDE tune was added when the timing belt was replaced, and has been running well for over a year. A vibration has developed in the last 6 weeks during vehicle operation between 45 to 55 mph when under cruising speed load. The vibration goes away (or is significantly less noticeable) under full throttle acceleration, and is not present under no-load (45-55 mpg and transmission in Neutral). Only seems to occur when cruising between 45-55 mph. No vibration when cruising at 70mph

The problem started when my wife started the vehicle and according to her, it ran rough, no power, had a hard time keeping the engine running. After driving for a mile or two, the vehicle died in a parking lot. She shut the vehicle off, then started it again and it ran fine. She took the vehicle to the Dodge/Jeep Dealer to see if they could recreate the issue, but were not able to. The only thing they told her was that the computer indicated a "misfire". I have since connected my OBD II code reader to the vehicle, and get no codes at all - no engine codes or transmission codes. Not sure what a misfire code means for a diesel. Anyway, the vibration started after she picked it up from the Dodge/Jeep dealer.

I have run the engine mount check per this forum on engine mounts, but there is no vibration when I shift from park/neutral to drive or reverse.

The barometric pressure sensor, MAF sensor, and turbo boost pressure (map) sensors were replaced when I replaced the timing chain.

I am thinking about re-flashing the GDE tune into the computer - Not sure if the Dealership may have messed up the Tune in any way.

Anyone have an Idea what this might be?
GreenDieselEngineering
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Joined: 10/07/2009 07:25:47
Messages: 348
Location: Southeast Michigan
The misfire code is real and could be bad fuel or just an ecm hiccup. Some folks that have the misfire can key off and wait 30 seconds, then restart and problem goes away. The vibration at a certain speed range sounds like a driveline issue. Best to check the brakes, axle, etc. for play and fluid levels. If you turn the OD off, does it still do it at that speed range?
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schwifi

Joined: 12/10/2017 00:00:27
Messages: 3
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Thanks for the response - the vibration is present in the 45 - 55 mpg range with the OD off (approx. 2000 rpm) - approx. 1800 rpm when OD on. It happens only under light load - cruising. Under acceleration, the vibration isn't there - or much less noticeable. Also, if I put the transmission in neutral in this range, the vibration goes away. I'll admit, the vibration does feel like an out-of-balance drive line - or what I would expect an out of balance drive line would feel like (I've never had one go out of balance before). But an out-of-balance drive line would vibrate when the transmission is shifted to neutral.

A little more about the maintenance of the vehicle. The front wheel bearings were changed about a year ago. The Turbo charger was also replaced about a year ago also - old one failed just after the GDE tune - I didn't see it but I guess the adjustable fins in the compressor flew apart. It had been making some noise before the GDE tune so it wasn't a surprise. When I installed the GDE tune, I blocked off the EGR tube going from the intake to the cooler. Also, the transmission has always had a intermittent hard shift from 2nd to 3rd when cold. Doesn't happen all the time, but it is noticeable when it happens.

Since this vibration didn't start until after my wife took it to the dealer to see if they could replicate the ICU hiccup, I was curious if they didn't reflash the ICU with the stock program. That would have turned the EGR back on, but I have it blocked, so was wondering if that isn't causing the vibration. It only happens in that range where the EGR would be active. The vibrations are less noticeable when cruising above 60mph. The ICU is not throwing any codes.

The last thing I though - maybe the EGR tube I blocked block is leaking high pressure air. This would cause the engine to be less responsive but not sure it would cause the vibration. I haven't checked this yet.

Any Ideas you have are welcome - will check the rear breaks also, as per you suggestion.
schwifi

Joined: 12/10/2017 00:00:27
Messages: 3
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The GDE reflash didn't help the vibration. Will check the EGR tube and rear axle.

Thx
mavalos
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Joined: 22/12/2016 11:06:25
Messages: 5
Location: Grand Junction CO
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schwifi wrote: ........A vibration has developed in the last 6 weeks during vehicle operation between 45 to 55 mph when under cruising speed load. The vibration goes away (or is significantly less noticeable) under full throttle acceleration, and is not present under no-load (45-55 mpg and transmission in Neutral). Only seems to occur when cruising between 45-55 mph. No vibration when cruising at 70mph ........

Anyone have an Idea what this might be?


I have previously (less than a year ago) posted a similar issue here with my '05 Liberty CRD. I have the Eco and trans Tune. All the rotating masses (front axles, drivelines, etc) have been changed. Diagnostics at one shop has more recently revealed that after the rear driveshaft was removed, the vibration ceased. Note: a "special" provision was made that would not allow TCase fluid to escape where the DS mates to the TC. Consensus was that it may be differential or wheel bearings. Or possibly the clutches in the Trac Lok unit. Another person posted on LOST Jeep forum that he was experiencing the same problem and after installing new carrier & wheel bearings, the vibration went away. He did not reveal whether it was the carrier or rear wheel bearings that were bad and he didn't respond to me asking.

However, I'm not convinced that perhaps that his problem is the same as ours / mine. I even thought it may be bearing related in the TCase. I'm very weary of throwing even more $$ at something that can't be better or more definitively diagnosed. The TCase and differential parts are high dollar stuff to be guessing. However, I don't know how to narrow it down anymore as to one or the other. *frustrated*
 
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