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11-03-2018
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Senior Newbie
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Join Date: Apr 2015
Location: Thornlands QLD
Age: 67
Posts: 69 What Jeep do I drive?: WJ
Likes: 29
Liked 11 Times in 10 Posts
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The 2.7 cams run directly above the engine valves using a hydraulic lifter(bucket) - twin cam - 4 valves per cylinder arrangement -non adjustable . Generally diesels do not like hi revs and sound like a can of marbles when revved hard eg 4000rpm . Injectors are electronic so they are quite -the hi pressure pump pressurizes fuel to about 15,000 psi (don't quote me -talking generally) and feeds to injectors via the COMMON RAIL -the injectors and timing of the injection spray is completely governed by the Engine control unit -ECU . On old diesel engines ,mechanical injectors spray pattern was created by fuel pump pressure pushing a plunger in the injector unit overcoming internal spring pressure to spray the diesel into the cylinder - not as efficient as electronic but cheap and very reliable -so generally electronic injectors are quite unless they U/S or blocked causing a bad spray pattern and "diesel knock" -incomplete combustion .
Black smoke under load - causes - blocked air filter - lazy turbo ,blocked intercooler (full of oil) - all of these intake restrictions are possible cause - after that is injectors - one other cause on the 2.7 is an injector may have been removed , but the copper washer that seals the injector in the bore was not removed (double washer thickness) on re installation .Sometimes a smokey diesel is cured by a long ,full engine load run if you have been putting around the city - EGR's should only work at low revs ,but if they are clagged out - they need to be removed and cleaned out .
Injectors on the 2.7 are the engines biggest problem as limited access to 4 and 5 and there are many ways of removal - pullers ,slide hammers ect - sometimes your lucky and can remove by soaking in CRC and twisting back and forward with spanner - rocker cover cracks easy - one puller I have requires the removal of the injector internals as it screws into the internal thread - often rendering the injector U/s - if #5 injector is completely seized,engine has to be dropped down by removing engine and tranny mounts to get access.
Leak test is the only way to go -cuts out all the guesswork -see my previous posts as good photos clearly illustrate what you are looking for.
You did not mention KLMs on your engine -Generally over 220,00klm injectors and hi pressure pump need doing -some people are lucky -most are not .
If you need a second hand turbo cheap - let me know - cheers
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11-03-2018
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Lowranger Shocker
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Join Date: Jul 2017
Location: SE Qld
Posts: 1,510 What Jeep do I drive?: WG
Likes: 172
Liked 273 Times in 220 Posts
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Thanks for the comprehensive reply. To clarify: - Just under 240,000km. It had just over 220,000km when I bought it last May
- I run the Torque Pro app as a boost gauge. I see 0.5bar at mild throttle (normal slow trafic take-off) peaking up to 1.5 bar if I mash it. I think the turbo is healthy.
- Given the above and that the pressure is measured at the manifold (after the intercooler) I doubt it is clogged with oil.
- A straight-edge reveals all injectors are at the same height.
- No black death. In fact, the injectors look very clean. I suspect they are not original, but I do not have any history.
- EGR has recently been disabled. I have manually applied and removed vacuum to it to ensure it is closed. I'm pretty sure it is. It idles really rough when I manually put vacuum on the EGR and smooth when removed.
- The engine does not use oil and is not fume out the oil filler or dipstick.
The smoke is not bad, but visible in the mirrors. I'm working on the assumption that if you can see your own smoke there is a fair bit of it. It is black - not white or blue.
I'll do a leak test, but it will be a few weeks before I can get the time.
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11-03-2018
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Senior Newbie
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Join Date: Apr 2015
Location: Thornlands QLD
Age: 67
Posts: 69 What Jeep do I drive?: WJ
Likes: 29
Liked 11 Times in 10 Posts
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Sounds like it is running reasonably for the KLMS on it -the other thing that has been known to happen is the Catalytic convertor downstream from the turbo can partially block and give the engine an asthma attack - hard to get full noise due to excess back pressure . One of the WG's I had was fitted with a 3"mandrel bent sports system straight off the turbo with no Cat - went hard .Fortunately the WJ/J's are not fitted with DPF -diesel particle filter which also robs power as engine ages . I've never seen black smoke in the mirror on any of my 3 x 2.7's ,so if you are fairly convinced everything else is OK ,the injectors are giving engine full fuel but turbo speed -air being forced into engine MAY be affected by Catalytic convertor . Most newer engines cannot give full fuel underload until required boost is reached to stop the black smoke but I do not know if the 2.7's ECU is that smart as it's early common rail technology -let me know how you go with the leak test.
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11-03-2018
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Rock Munki
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Join Date: Aug 2009
Location: Castle Hill, NSW
Posts: 2,136 What Jeep do I drive?: WG
Likes: 11
Liked 300 Times in 245 Posts
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A clogged inlet manifold could richen up the mixture and generate a bit more black smoke. A can or two of inlet manifold cleaner probably wouldn't go astray.
A leaking injector could also add to the black smoke problem.
Oddly enough an EGR delete will kill the black smoke, it is worthwhile doing.
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12-03-2018
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Senior Newbie
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Join Date: Apr 2015
Location: Thornlands QLD
Age: 67
Posts: 69 What Jeep do I drive?: WJ
Likes: 29
Liked 11 Times in 10 Posts
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Forgot to mention - clean the MAF sensor - use MAF cleaner available in spray can from most large auto stores -do not use brake cleaner ect as it can affect the plastic on the unit -easy job compared with most on the 2.7 -couple of hose clamps on the air induction -should be done as part of a major service along with the camshaft positioner sensor if you want peak performance !
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12-03-2018
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Lowranger Shocker
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Join Date: Jul 2017
Location: SE Qld
Posts: 1,510 What Jeep do I drive?: WG
Likes: 172
Liked 273 Times in 220 Posts
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Funny thing... I just purchased a can of Wurth cleaner. EGR delete done.
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13-03-2018
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Rock Munki
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Join Date: Aug 2009
Location: Castle Hill, NSW
Posts: 2,136 What Jeep do I drive?: WG
Likes: 11
Liked 300 Times in 245 Posts
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Quote:
Originally Posted by almc3
Forgot to mention - clean the MAF sensor - use MAF cleaner available in spray can from most large auto stores -do not use brake cleaner ect as it can affect the plastic on the unit -easy job compared with most on the 2.7 -couple of hose clamps on the air induction -should be done as part of a major service along with the camshaft positioner sensor if you want peak performance !
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If you don't have a catch can installed on the PCV you will find the MAF is very oily. Cleaning the MAF is definitely a good thing to be doing.
Jason
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