Hi Everyone
I am writing from Darwin, a smallish city in the very north of the Australian continent. I have an 07 diesel manual JK Sport. 70,000 gentle (maybe too gentle) kilometres. I only doodle around the back blocks of my rural area mainly off road. I rarely take it into the city. It has been a lame duck for 6 months. The turbo only comes on when it wants to. Two sets of good mechanics have spent a huge amount of time on it. In addition to a brand new OEM Garret turbo (which made no difference) they have cleaned and changed just about everything you can think of. Eventually they spoke to the techsperts at Chrysler/Jeep in the USA who made various suggestions, none of which worked. Now the US Jeep experts have washed their hands of it - saying that they cannot fix it. At one point it looked as though a rat might have chewed an essential wire. Rats had chewed an iPod connector in the glove box. The car had been stored in a shed for 6 months over the monsoon season. It was fine when I put it in the shed - but was not fine when I took it out - flat battery too. But the fact that the turbo works sometimes should rule out rodent tampering (if a wire is cut - it stays cut?) also, the turbo can be switched on manually by cutting the engine for a second (while driving) and turning ignition back on. When the engine fires up again - the turbo always works. That is, until I slow down for a corner and change gear. Then the turbo often (but not always) goes to sleep again.

So, $4,000AU later - I have a great car that only occasionally comes to life and does what it is supposed to do. I can't fix it and I can't sell it. Right now I am trying to get a second hand ECU (with all the ignition and key trimmings) in the hope that the problem is a faulty weld on a chip in the ECU - as has been suggested by a couple of mechanics. The ECU has been reflashed - but that won't change anything if there is a dry weld somewhere.

Have any of you people got any other suggestions?

Waiting with keen interest.

I'm not at all familiar with the 07 JK CRD.
But whenever there is a boost problem I start by checkung the MAP sensor and its wiring.
And if your 07 JK is like my 05 KJ, I would also check the vacuum lines and solenoids, behind the air filter box, that control the turbo actuator.

Is your check engine light on?
Can you scan for codes?
Knowing the trouble codes would be a big help.

_________________
U.S. Army Retired

If it has a vacuum solenoid that opens when the ignition switch is turned on like our US Jeeps, it may very well be the culprit. You can bypass this solenoid when it is in the limp like running mode you describe and see if it brings it to life. If it does, you have identified your problem; replace the solenoid! Bypassing the solenoid will not hurt or damage anything...
Keep us posted!

It is the item with the red dot in the picture:

_________________
Supporting Vendor and Moderator of LOST
05 Jeep Liberty CRD Limited
Ironman Springs/Bilstein/Shocks
Yeti StgIV Hot Tune
Week's BatteryTray
No FCV/EGR
Samcos/ProVent
SunCoast/Transgo
Carter Intank-pmp
2mic.Sec.Fuel Filter
Flowmaster/NO CAT
V6Airbox/noVH
GM11 Bld.fan/HDClutch
IronrockArms/wwdieselMount
98 Dodge Cummins 24 Valve

Hi WW

I had a quick look under the bonnet but could not see anything looking like what you show. But I will take it to my mechanic next week and see what he thinks. I don't think that this item has been looked at yet - if it exists on my car.

My mechanic has been great. he has spent hours on this so far and has only charged me for a few. He has taken it on as a personal challenge. he said that only 2 cars have beaten him in his career. Unfortunately, that number has now risen to three. Just wish it weren't my car to be number three!

All suggestions are welcome.

Cheers

Can you post some pictures of the engine compartment under the bonnet, maybe we can spot the part in question!
On left hand drive US models, it is located on top of the passenger side fender well next to the power steering reservoir as per the picture...
Trace your vacuum line from the turbo actuator back to what it is connected to and you should be able to find it...

_________________
Supporting Vendor and Moderator of LOST
05 Jeep Liberty CRD Limited
Ironman Springs/Bilstein/Shocks
Yeti StgIV Hot Tune
Week's BatteryTray
No FCV/EGR
Samcos/ProVent
SunCoast/Transgo
Carter Intank-pmp
2mic.Sec.Fuel Filter
Flowmaster/NO CAT
V6Airbox/noVH
GM11 Bld.fan/HDClutch
IronrockArms/wwdieselMount
98 Dodge Cummins 24 Valve

A quick look on Wikipedia shows the 2007 JK with the vm RA428 which is a little different from the R428 in our libertys. I believe that the RA has an electrically actuated vgt, not vacuum. To me it sounds like a bad map sensor and it's cutting boost to protect the engine. On the R428 the computer verifies readings between map and baro sensors after being below a certain rpm for 15 secs or something like that. But the newer motors ecm may be programmed differently.

_________________
05 Liberty crd 185k miles / Lifters and rockers, arp studs, h.d.s. thermostat, weeks stage 1+2, carter lift pump with sasquatch harness, gen 2 filter head, hemi t/c, 245/70r16 bfg a/t ko2, on board air, uniden pro 520xl
4.10s with a detroit locker in the rear and e-locker up front
Next up....skids and GDE eco FT.

Hi Flash
I don't get it. I wrote you a lengthy answer - but it disappeared when I pressed the submit button! Not happy.

I will write it all again and get back to you.

Hi Locked

Yes, I think you are right. There is no tube attached to my actuator. Just a neat rod linkage and the electrical connectors.

I am new on this forum so don't know anything about the "Wikipedia". I will check it out. I am also not a mechanic so I don't know much about cars either. But I was a Chef Ranger here in the tropical Northern Territory of Australia for 30 years - so I know a bit about 4 wheeling. I had Toyotas at home and at work all my working life. They were good, but the Wrangler makes me smile (when it is working) in a way that a Toyota never did.

When I look at the list of work done on my car - I see that they have worked on the MAF (Mass Air Flow Sensor). Is that the same as a MAP?

Cheers

Hi Flash

here I go for a second time:

Yes, the check engine light is on pretty much all the time. It even stays on when the turbo is working. Rarely it will go off, but soon comes back on again.

These are the codes that have been thrown:
P0402 EGR Flow Excessive detected
P0101 Mass Air Flow Sensor "A" circuit performance. Air mass meter was reading 19 gms/s. Should be 3gms/s
P0299 Turbo Under Boost
C121A Steering Angle
B1A28 ECM Mismatch with SKIM

Work done includes, Attempt one: -
Air filter inspect
Intercooler hose inspect
Smoke test of air charge system
Found turbo actuator not to be working. Fitted complete new turbo and actuator - no change to problem.

Attempt two with code reading "under boost": -
Inspected air intake hose
Inspected all wiring looms - short of taking out dash board
removed exhaust and inspected
Ran camera down intake system
Removed and cleaned EGR valve
Removed and cleaned Mass Air Flow (MAF) sensor. No change
Swapped MAF with a known good one. No change
Removed and inspected boost sensor.
Removed and cleaned intake temp. sensor
Mapped boost sensor. Found actual values to be different to target values - turbo only making boost at high revs (sometimes)
Techsperts advise pressuring intake system. No leaks found.
They then advised disconnect intake pressure sensor and test. Same fault persisted.
Replaced intake pressure sensor - no change.

And then they told me to come and take it away

My local mechanic thinks it must be a bad weld within the ECU. This has been reflashed of course. But a reflash won't fix a dry weld in the circuitry. We are trying to find a second hand ECU here in Australia. But diesel manual JK Sport Wranglers are a rare breed and we may not be able to get one.

We suspect that there is nothing mechanically wrong with the car. We think it must be an electronic glitch somewhere in the engine management system. A false message is telling the car to go into limp mode and deactivates the turbo, something like that. But it is a needle in a haystack situation.

Cheers

The MAF (mass airflow) sensor measures the volume of air coming through the airbox.

The MAP (manifold absolute pressure) sensor measures the amount of boost at the intake manifold.

But it sounds like it did get checked. The map sensor can also be referred to as a boost sensor and it also sounds like they may be referring to it as the intake pressure sensor mentioned in your post.

Before just replacing the ecm, you or your mechanic should make sure it has power and ground. Also if you do get a replacement ecm it will need to have your vin# flashed into the new one in order to run. I learned the hard way about all the funny things a bad or disconnected ground can do

_________________
05 Liberty crd 185k miles / Lifters and rockers, arp studs, h.d.s. thermostat, weeks stage 1+2, carter lift pump with sasquatch harness, gen 2 filter head, hemi t/c, 245/70r16 bfg a/t ko2, on board air, uniden pro 520xl
4.10s with a detroit locker in the rear and e-locker up front
Next up....skids and GDE eco FT.

Hi Locked
Thanks for that.

I sure will get them to check the grounding at the ECM.

My mechanic explained some of the complexity of changing the main brain. He has taken down all the identity details and is considering the keys, ignition and those sorts of things. We understand that it would have to go to a dealership where they would reprogram things to match.

But - as you suggest, we will confirm the "power and ground" first.

Cheers

There was a code for excessive EGR flow in there. I wonder if the EGR is sticking open or failing to function at times. This would cause boost to be lost would it not? Fitting a block off plate would be a fairly quick and simple test to see if this is the problem. I am fairly new to these engines so maybe one of the more experienced members can chime in on weather my idea is plausible or not.

Hi Petey

Thanks for that. yes, this is why I am on this forum - I reckon there are experienced people out there who would know more than my local dealership - at least for some specialised problems like mine.

And no - the problem does not come from driving around upside down as we all do down here in Australia!

My first question after that laundry list of attempted diagnosis is why when they did not see the electrically powered actuator to the turbo move did they not verify the proper voltage was indeed even being sent to the turbo?

You need to find someone that actually knows how to use a quality multimeter to trace out some of these wires to ensure you do not have a break or bad connection. The intermittent on and off makes me think it is just that.

Sent from my SM-N910W8 using Tapatalk

_________________
2006 Liberty CRD Limited

Provent @ 43,000 km
SEGR in progress
SAMCO Sport hoses @ 48500 km
Goodyear Wrangler Duratrac LT225/75R16

Hi WolverineFW

I can't answer that question. I guess they were relying on the code that said "Turbo underboost". They did a series of tests on the turbo - but I can't say if they did that one in particular. If you are right, then the finger points back towards rat damage - maybe. I guess a rat could semi-sever a wire, which then works sometimes. I have noticed that it is more likely to work when everything under the bonnet is hot.

But in the meantime - my local guys have found a second hand "brain" (ECM, CPU, ECU - whatever) and are installing it late this week or early next week. I will keep you posted.

Thanks for your comment.