Underboost diagnosis

Gypsy62 · **Posted:** Mon Sep 23, 2019 3:01 am

The (presumed) original turbo is my benchmark for "normal" boost: jeep was a "rocket sheep" pre turb removal, albeit with intermittent "limp" mode symptoms.

The newly-installed unit from Dieselsite disappoints: major underboost & slight blow-by.
CODES: customary EGR (@ Sasq 1/2: haven't yet synthesized ECM). That's it.

Diagnostics thus far:
- Confirmed entire intake path unobstructed and holding pressure, air filter fine.
- Turbo "boosting" to some degree, confirmed @ my 1/8th"npt intake tap. Boost/EGT gauge coming soon*.
- Correct Timing Confirmed (Fun!).
- I have hesitated to pull the int. man. to check for rocker failure; less than 5k miles since replaced!

Multiple Test Drives:
Worth mentioning that I removed the serp belt & tbelt cover plate (for timing inspection) & then re-mounted the harmonic balancer for test drives. Even with no serp resistance, still sub old-turb pep off-the-line.
- Vac solenoid bypassed; minor boost increase, if any.
- MAP cleaned; possible minor increase in boost (new map ordered).

The underboost issue is vexing. The beast was breathing fire until my turb went South, so it seems hard to blame other systems.
- Fuel Related? New Filter has under 50 miles. Filter head update/Kennedy lift <5k miles.
Opinions welcome.

Peripherally:
- This "New" turbo is still very lightly blowing oil. However, imo ANY blow-by should be unacceptable in a new unit. Probably replacing with a Garrett ball-bearing unit (thanks, Joe!). I'll have turbo's custom oil supply/drain fittings machined w/drain "Y" to accept Provent drain. Updates later.
- Other posts suggest ECU tune challenges with the larger turb. My 3" exhaust, elec. fan setup & (coming) intake snorkel may compound the math.
- Seriously considering rebuilding the shortblock w/ "Totalseals". Opinions? About 160k on engine and I'm on the fence whether necessary or advisable. Before original turbo failure, lotsa' power. Never did compression test (only have gas eng comp/leakdown tester). Subsequently, question re to what degree blow-by @ pcv was turbo leaking vs worn rings.
- *I just ordered a "Glowshift 3n1" combo Boost/EGT/(AT fluid)Temp gauge w/sensors. I like the multi-function single gauge concept but @ $200 I'm a bit weary of accuracy/durability.
Any reviews of Glowshift gear?

Thanks

Keys: Liberty CRD turbo problem weak failure under-boost underboost under boost

GordnadoCRD · **Posted:** Mon Sep 23, 2019 7:18 pm

As you report, pre-garrett-failure:, your performance was acceptable

Post Turbo Replacement: performance not acceptable in many ways.

I'd say this limits the problem pretty well. Nothing surrounding the turbo, from vacuum, oil supply, blow-by, or anything else has presumably changed.

Your ultimate solution is to send your Garrett to Diesel_guy86 (Blackbird Industries?) for his rebuild/mods, (or , more ultimately , exchange for his full ceramic roller product he's recently completed)

As far as the Dieselsite turbo goes, mine was a little like that for the first 5000miles or so. I don't know for sure why, but I wrote it off to minor changes to the vane control rod, and time for the turbo bushings to "break in" or loosen up. Again, I don't know if it's even a thing, but it's how mine acted. My chats with Joe indicated it may be related to the WickedWheel that Dieselsite uses

As far as oil coming into the charge-air system, I have had that all along, but like you, there were no changes to my short-block.

As far as tearing the short-block down, unless you have rear main bearing leakage, I'd recommend leaving it alone. The factory system to deal with this is still working as before, and if the oil is a bothersome issue, There is always the https://shop.sasquatchparts.com/products/mann-provent-200-3931070550/ which is available as the original product and plumbed in the way we have done in the past, or there is the newly available custom install kits to lighten your wallet and simplify your experience. https://shop.sasquatchparts.com/products/bundle-sasquatchparts-provent-kit-mann-provent-200-oil-separator-jeep-liberty-28l-crd/
Much MUCH cheaper than tearing your shortblock out and refreshing it in ANY way.

As far as Glowshift, I think WWDiesel may use some of this gear.
I have never had a failed, faulty, or inaccurate AutoMeter gauge , so I've never used anything else. Sorry for my inexperience in that. I know there are cheaper options, but I've stayed with AutoMeter.

Good luck Gypsy, whatever you choose.

WWDiesel · **Posted:** Mon Sep 23, 2019 11:04 pm

I have two Glowshift gauges, boost and transmission temperature. Very satisfied with both and have had no issues with either one.
As for the three in one Glowshift gauge, I have no experience with it. Personally I don't like the idea of putting all in one, too confusing.

Gypsy62 · **Posted:** Wed Sep 25, 2019 3:19 am

It's worth repeating that while testing these turbos I removed the hose from the CCV(PCV), allowing it to vent directly to air. Therefore, elevated case pressure could not have been responsible for causing blow-by at the turbos' journal bearing. A Provent 200 has arrived to replace my similarly-functional but less-elegant DIY. I am going to tap the provent's vent-out into the 3" exhaust downpipe.
I'm going to water-cool the incoming Garrett ball-bearing turbo. That will leave the high/low oil-pressure supply/return ports at the block vacant:
- The High Pressure port can be used for mounting an Oil Pressure Sensor for a gauge.
- The Return Line's port can be dedicated to the Provent's oil drain line.

Question for the Brain Trust:
Which coolant line would it be best to intercept to install the feed and return to the turbo?
I am already stressing about the spectre of sudden coolant loss frying the turbo... maybe a separate coolant pressure gauge would provide comfort if not adequate warning.

Re gauges, thanks for your input.
It's a good idea to start a new thread on the subject.
Cheers

WWDiesel · **Posted:** Wed Sep 25, 2019 11:42 am

Gypsy62 wrote:

It's worth repeating that while testing these turbos I removed the hose from the CCV(PCV), allowing it to vent directly to air. Therefore, elevated case pressure could not have been responsible for causing blow-by at the turbos' journal bearing. A Provent 200 has arrived to replace my similarly-functional but less-elegant DIY. I am going to tap the provent's vent-out into the 3" exhaust downpipe.
I'm going to water-cool the incoming Garrett ball-bearing turbo. That will leave the high/low oil-pressure supply/return ports at the block vacant:
- The High Pressure port can be used for mounting an Oil Pressure Sensor for a gauge.
- The Return Line's port can be dedicated to the Provent's oil drain line.

Question for the Brain Trust:
Which coolant line would it be best to intercept to install the feed and return to the turbo?
I am already stressing about the spectre of sudden coolant loss frying the turbo... maybe a separate coolant pressure gauge would provide comfort if not adequate warning.

Re gauges, thanks for your input.
It's a good idea to start a new thread on the subject.
Cheers

1. Reminder, the CCV requires the negative suction pressure of the turbo inlet for efficient operation and to help prevent any pressure buildup in the engine crankcase. It was designed that way by the engineers.
2. The oil drain line on the ProVent must be plumbed below the engines oil level or you will nave to install a non-return check valve for it to drain properly.
3. For coolant supply and return to the turbo, I would use the original places the EGR cooler used.
Supply, center port on head; always under full pressure of water pump discharge.
Drain, plumbed into the heater core return which goes into the low pressure of the water pump suction.
This would insure a good flow under all engine operating conditions.

:SOMBRERO:

Gypsy62 · **Posted:** Wed Sep 25, 2019 2:36 pm

Many Thanks for coolant port-tap counsel, WW!!!

Re provent oil-return back-pressure, I purchased the check-valve at same time. Thanks for heads-up.

Re vacuum @ CCV, with the hose off there is plenty of vent-pressure even without any applied intake-vac. That makes it difficult for me to absorb that hosing it to the intake vac induces a 'crucial' reduction in case pressure.
Anyway, I'm going to tap a "Y" pointing downstream within the exh. downpipe to accept the provent vent-out line.
In theory, the higher-volume of the 3" exhaust passing around the smaller (5/8"?) pipe orifice should create some measure of venturi-effect vacuum, No?
Post-install, I'll grab a vac gauge to confirm. Given the effort/expense to mod, hope I'm right...

WWDiesel · **Posted:** Wed Sep 25, 2019 5:18 pm

Gypsy62 wrote:

Many Thanks for coolant port-tap counsel, WW!!!
Re provent oil-return back-pressure, I purchased the check-valve at same time. Thanks for heads-up.
Re vacuum @ CCV, with the hose off there is plenty of vent-pressure even without any applied intake-vac. That makes it difficult for me to absorb that hosing it to the intake vac induces a 'crucial' reduction in case pressure.
Anyway, I'm going to tap a "Y" pointing downstream within the exh. downpipe to accept the provent vent-out line.
In theory, the higher-volume of the 3" exhaust passing around the smaller (5/8"?) pipe orifice should create some measure of venturi-effect vacuum, No?
IN theory yes, let us know how well it performs. And many on LOST have stated that anything over a 2.5" pipe is an overkill and waste? Not sure on this one!
Post-install, I'll grab a vac gauge to confirm. Given the effort/expense to mod, hope I'm right...

Please read this (kinda long) and draw your own conclusions:
Excessive CCV or Engine Blowby viewtopic.php?f=5&t=80491

Meant to post this drawing in earlier post:

Gypsy62 · **Posted:** Fri Sep 27, 2019 12:21 am

Thanks for the graphic, WW!

I back-drafted the link. It seems most concerns re the EHM were cold-climate based (= freezing). At least at my current latitude, that doesn't apply to me.
Anyway, I now have a Provent in-hand...

The "engineers designed for a slight vacuum applied to the CCV"...
Okay. Even absent frigid temps, my objective is to replicate that intake "slight vacuum" venturi effect except at the exhaust side. Hope it works.

However, I maintain that blow-by at a NEW turbo should not pivot on the addition of that "slight vacuum". Especially with the CCV blowing wide-open with no hose attached? No Way. Not Acceptable.

This Spring I replaced the Gulliverian rear main seal assembly (during trans rebuild); in '16 I replaced the insufferable F'ing OEM SINGLE-lip front main seal with a hard-searched twin-lip substitute (during HG/TBelt/ Rockers, etc). However, even before I performed those major surgeries on my beast I never had leaks at either front/rear seal. So, whatever case-pressure prevailed it violated neither the main seals nor the old turbo's journal bearing seal.

If you haven't noticed that your time is finite, pay attention.
I would rather be doing almost anything than working on a jeep that should be reliably delivering me to worthy coves and caves, bluffs and beaches. Too old for this. Grrr.

That does not, however, mean that I am not immensely grateful for the knowledgeable insight and advice of the LJ Brain-Trust. To the contrary.
Thanks!

WWDiesel · **Posted:** Fri Sep 27, 2019 2:49 am

Gypsy62 wrote:

Thanks for the graphic, WW!

I back-drafted the link. It seems most concerns re the EHM were cold-climate based (= freezing). At least at my current latitude, that doesn't apply to me.
Anyway, I now have a Provent in-hand...

The "engineers designed for a slight vacuum applied to the CCV"...
Okay. Even absent frigid temps, my objective is to replicate that intake "slight vacuum" venturi effect except at the exhaust side. Hope it works.
If you have no CAT and a free flowing muffler to prevent any back pressure, in theory your exhaust negative pressure device should function adequately.

However, I maintain that blow-by at a NEW turbo should not pivot on the addition of that "slight vacuum". Especially with the CCV blowing wide-open with no hose attached? No Way. Not Acceptable.
I totally agree with this statement.

This Spring I replaced the Gulliverian rear main seal assembly (during trans rebuild); in '16 I replaced the insufferable F'ing OEM SINGLE-lip front main seal with a hard-searched twin-lip substitute (during HG/TBelt/ Rockers, etc). However, even before I performed those major surgeries on my beast I never had leaks at either front/rear seal. So, whatever case-pressure prevailed it violated neither the main seals nor the old turbo's journal bearing seal.

If you haven't noticed that your time is finite, pay attention.
I would rather be doing almost anything than working on a jeep that should be reliably delivering me to worthy coves and caves, bluffs and beaches. Too old for this. Grrr.

That does not, however, mean that I am not immensely grateful for the knowledgeable insight and advice of the LJ Brain-Trust. To the contrary.
Thanks!

My only intent was to bring awareness to some of the quirky things we have learned along the way about the design functions on this engine. Some were learned the hard way by some. Did not want you to design yourself a problem. :5SHOTS:

Underboost diagnosis

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