MAP Sensor Pics after 37K miles with GDE Eco Tune/EHM

usa591 · **Posted:** Sun Dec 28, 2014 2:28 am

Hi All,

I installed my ProVent last week and spent this weekend doing some maintenance. One of the things I did was pull the MAP to inspect and clean it. I figured the pics were worth sharing.

This is approximately 37,000 miles and four years after installing the GDE Eco Tune and doing the EHM, which was when I cleaned it last.

Any thoughts on how efficiently this is working in this condition?

papaindigo · **Posted:** Sun Dec 28, 2014 12:17 pm

Would work better with a cleaning but even with a GDE tune that's not all that dirty given the time and miles.

usa591 · **Posted:** Sun Dec 28, 2014 12:33 pm

...yup, cleaned it before I put it back in.

One thing I'm noticing is that it is mostly dry, not covered in the oily soot that I noticed when I first pulled it at about 40,000 miles.

flman · **Posted:** Sun Dec 28, 2014 12:41 pm

Mine was even cleaner, just had a coating of oil on it, I just put it back in as is. :2cents:

gmctd · **Posted:** Sun Dec 28, 2014 12:54 pm

usa591 wrote:

Hi All,

I installed my ProVent last week and spent this weekend doing some maintenance. One of the things I did was pull the MAP to inspect and clean it. I figured the pics were worth sharing.

This is approximately 37,000 miles and four years after installing the GDE Eco Tune and doing the ORM, which was when I cleaned it last.

Any thoughts on how efficiently this is working in this condition?

You'll notice there is no oil on the sensor, result of GDE tuning and ORM diverting crankcase effluent - those are carbon deposits resulted from EGR function
All appears copasetic, positive result from the modifications
If you correctly connected the PROVENT, you will begin to see some light oil coating resulted from PROVENT-filtered crankcase vapor effluent - won't be anywhere near as bad as oem setup was

ArmyChief · **Posted:** Sun Dec 28, 2014 1:45 pm

GDE Tune STILL has EGR activated on decel. Be interesting to see what it would look like if you installed Sasquatch MS Intake Elbow kit with EGR block-off plate.

DOC4444 · **Posted:** Sun Dec 28, 2014 7:02 pm

What is the point of running ORM with a GDE tune? GDE tune does a much better job of reducing EGR function than ORM. Also, you have been driving with a CEL on so you have no way of knowing as soon as a real problem pops up.

Army, I have been involved with GDE since they first started doing performance tuning. My understanding is that GDE tunes only open the EGR on the KJ CRD in the rare situation when you are into the throttle suddenly lift off, then jump back on. Otherwise, EGR stays closed.

DOC

ArmyChief · **Posted:** Sun Dec 28, 2014 7:04 pm

DOC4444 wrote:

Army, I have been involved with GDE since they first started doing performance tuning. My understanding is that GDE tunes only open the EGR on the KJ CRD in the rare situation when you are into the throttle suddenly lift off, then jump back on. Otherwise, EGR stays closed.

DOC

DOC,

Thanks for more info. I called Kieth when I bought my CRD and asked about the EGR. I got the impression from him it opens on ALL decels.

GreenDieselEngineering · **Joined:** Sun Jun 07, 2009 5:10 pm **Posts:** 1111

The egr will only open if the turbo charger surging algorithm requests it, not on every decel. There has to be a pressure differential to flow boost backwards through egr circuit and that is the primary driver in the algorithm. rpm is the other main factor.

Allowing more turbo surge on throttle tip out will only increase the low cycle fatigue failure on the compressor wheel and lessen bearing life.

ArmyChief · **Posted:** Sun Dec 28, 2014 7:12 pm

thanks

WWDiesel · **Posted:** Sun Dec 28, 2014 8:34 pm

Why in the world would you want a functional EGR valve at all? Makes absolutely no sense to me!!! :roll:

First thing I did to the Jeep when I purchased it was to block off the EGR with a plate after reading all the horror stories about the soot and goo problems in in the motor and intake...

With the Squeeto/Yeti self installed tune, I have no EGR function (its gone anyway), no FCV function (its gone), no DTC light (check engine light) and a VERY clean MAP sensor and the cost was $0.
Very hard to beat!!! :BANANA:

ArmyChief · **Posted:** Sun Dec 28, 2014 9:00 pm

WWDiesel wrote:

Why in the world would you want a functional EGR valve at all? Makes absolutely no sense to me!!! :roll:

I used to agree..coming from the Powerstroek/Duramax arena...everyone deletes the EGR. However, Keith's statement, "Allowing more turbo surge on throttle tip out will only increase the low cycle fatigue failure on the compressor wheel and lessen bearing life."

Makes me wonder. I've never heard this thought process for the Fords or Duramax's

Lastly, if allowing the EGR to still function to alleviate any possible pressure differences between intake and exhaust sides of turbo, would that outweigh allowing the EGR to still function and carbon in the intake?

With no throttle body/FCV....pressure in intake should be minimum during decel and with a larger exhaust, possible no muffler..unlike a gas motor..back pressure in exhaust near zero is optimum. Is there a large pressure difference?

Not doubting Kieth, he is well respected....I would just like to read more on this phenomenon.

usa591 · **Posted:** Sun Dec 28, 2014 10:06 pm

DOC4444 wrote:

What is the point of running ORM with a GDE tune? GDE tune does a much better job of reducing EGR function than ORM. Also, you have been driving with a CEL on so you have no way of knowing as soon as a real problem pops up.

Sorry, my bad--I was running the EHM mod. No CEL's.

I finally got my act together to install my ProVent when I was stopped at a light next to a Black & White and I could see the one officer say to the other, "what's all that smoke?" when they were looking at my CRD. Here in CA I could get pulled over for being a "gross polluter".

ArmyChief · **Posted:** Sun Dec 28, 2014 10:35 pm

Its and older thread, but would seem to support that even with the GDE tune, Exhaust SOOT IS flowing through the intake. Referenced by the OP MAP pictures posted above (with only 37K on it) and the oil color and more importantly the EGR blocking plate soot buildup referenced in the below link.

viewtopic.php?f=5&t=72945&start=0

I've been reading for hours (here and other places...BWD and Honeywell white papers too)

gmctd · **Posted:** Sun Dec 28, 2014 11:06 pm

Back off the acc pedal suddenly, APPS causes ECM to pull fuel at the injectors, no fuel = reduced exh energy into the turbine results in reduced drive on the compressor vanes against impedance of BOOST pressure, resulting in immediate turbo spool-down while vehicle momentum driving thru TCC keeps engine rpm from dropping as rapidly as BOOST is dropping

What levels of "surge" have been seen in street scenarios, vs LAB scenarios where dyno loading results in rapid rpm drop at instant of fuel-pull - 'nuther words, where suddenly-reduced APPS input causes ECM to go to idle-fuel from full-fuel full BOOST conditions?

ArmyChief · **Posted:** Sun Dec 28, 2014 11:29 pm

gmctd wrote:

Back off the acc pedal suddenly, APPS causes ECM to pull fuel at the injectors, no fuel = reduced exh energy into the turbine results in reduced drive on the compressor vanes against impedance of BOOST pressure, resulting in immediate turbo spool-down while vehicle momentum driving thru TCC keeps engine rpm from dropping as rapidly as BOOST is dropping

GM,

I'm aware at what "surge" is and what causes it (pressure differences). However, I believe..wanting to have an educated conversation, as you and I have talked before, that there are factors in our Libby's that reduce to a bare minimum and possibly negate the risk of having apparent soot ingested.

As seen with the above MAP picture with a GDE tune and 37k, there is soot on the MAP sensor...no denying that. As seen in the two year old thread I posted, there is a higher accelerated oil color change and soot on the exhaust side of the EGR blocking plate. With those three statements (with no other data), we can hypothesize that with a GDE tune, when the EGR IS opened..pressure on the exhaust side is HIGHER than the intake side. This would facilitate exhaust to flow from the higher pressure region to the lower pressure region..yes?

Now, don't take this conversation of soot and EGR as a slam on GDE, its not. I have their tune and think it is the single most BEST thing to do to our vehicles known. This is ONLY a educational thread and investigation of intake soot.

Based on my research and previous knowledge, it would appear that using the EGR or Turbo vanes to equalize pressure is more functional on 2007+ diesels that have DPF & SCR...IE a higher exhaust back pressure (and gas engines with a throttle body) then our Libby's. Especially since unlike a gas vehicle where computed and engineered back pressure is a necessity, on a turbo diesel, ZERO back pressure is the GOAL.

So, if a Libby CRD owner removes or puts on a much less restrictive muffler 9cat back) exhaust and reduces their back pressure dramatically, then turbo surge theoretically should also diminish.

Lastly, I think ultimately the owner, after doing their due diligence, will have to determine if a sooted up intake, MAP and possible accelerated engine component wear out weighs the possibility of a turbo failure DUE to surging (and not some other mechanical or more importantly oiling reason).

Thanks for ALL the great info and conversation!

WWDiesel · **Posted:** Mon Dec 29, 2014 6:07 am

Very simple solution for all of this as some of us have already done!
No matter what tune you have, stock, GDE, Yeti, or SEGR, get the Weeks FCV elimination elbow kit and install it! No possibility of any EGR (SOOT) getting into the intake anymore.
Problem solved.... :-)r

You know, if I were really concerned about any high overpressure or backpressure during any mode of operation, I would simply add a blowoff valve like the gassers run on their turbo systems. There are plenty available on the Web and very simple to install.... :?:

rancherman · **Posted:** Mon Dec 29, 2014 9:52 am

Armychief:

The pressure differential isn't downstream of the turbo in the exhaust pipe. It's the difference in the drive pressure, and the intake pressure.
Think of the intake side (from compressor wheel- all the way to the intake valve) as a reservoir of compressed air. Lets say you are buzzing along @ 18 psi.. and suddenly backed out. 'drive pressure' leaving the engine goes down almost immediately.. ( the fire was put out) but there is a brief moment there is still 18 psi in the samcos, the intercooler itself, and the intake manifold.

This is when the turbo can suddenly change directions, which is the hard part on bearings.. well anything that is moving is 'jarred' pretty harshly. Each time this happens, it happens 2x. first time to run backwards, and a split second later again to resume normal direction.
In actuality, REDUCING back pressure with a larger exhaust, no muffler, or cat, will make this phemon WORSE. (because the 'drive pressure' will not be reduced/dissipated as fast during defueling) The 'overlap' of pressure differentials won't be near as long, or intense

gmctd · **Posted:** Mon Dec 29, 2014 12:32 pm

My posit was for GDE, considering that the engine is also a massive air pump which would not stop pumping air when APPS is suddenly reduced, and would not 'spool-down' nearly as quickly as would the turbocharger

APPS = Accelerator Pedal Position Sensor - we don' need no steenkin' gas-pedal throttle

And, of course, turbo CFM must be much greater than engine CFM, or you wouldn't get BOOST

Street-wise, vehicle speed and drivetrain rpm are a load on the engine - cut fuel and vehicle momentum\inertia would continue to drive the engine air-pump, pumping BOOST out the exhaust as vehicle speed dropped\slowed - almost instantaneous turbo spool-down cutting BOOST much quicker than engine is pumping it out

Lab-wise, the dynomometer is a load on the engine - cut fuel and that load would immediately drop engine rpm much quicker than in the street scenario, more easily producing the described effect of compressor-reversal

However, as rancherman pointed out, and which I was forgetting (I've slept some since back when, so sue me, eh), combustion-derived exhaust energy into the turbine suddenly drops, much quicker than the big air-pump driven by vehicle momentum can spool-down - instantaneous result in drive-to-pumped pressure differential across the turbo, turbine to compressor, can be 'bark', as per his explanation

So, per GDE, their 'tunes' are set to prevent this damaging effect, long as nobody jacks with the mix

ArmyChief · **Posted:** Mon Dec 29, 2014 1:06 pm

gmctd wrote:

So, per GDE, their 'tunes' are set to prevent this damaging effect, long as nobody jacks with the mix

I'll allow you to sleep...just this one time

However, I believe the EGR is open MORE than just during a programed surge condition (see original OP pictures, my post and referenced post above). When I have time..if I have time, I will hook up my picoscope to the EGR and monitor under various conditions with scantool connected.

MAP Sensor Pics after 37K miles with GDE Eco Tune/EHM

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