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 Post subject: MPG issues
PostPosted: Wed May 08, 2019 5:00 pm 
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I have driven about 2k miles since getting the libby but I was hoping for better mileage. I'm getting a consistent 22-23 mpg, I am a light foot driver and it is 70/30 highway city, I get the high end of estimated mileage from all of my other rigs. New fuel filter, oil and oil filter, I am running LT tires but they are snow rated traction tires not AT's. I do have the GDE hot tune (i know but GDE states same map until 80%+ throttle as the eco tune) in hand but I am waiting for a TC before I flash it. It did sit for two years before I got it running again, but afaik there is no boost leaks currently, new turbo to cac hose and inspected the cac to engine hose, no significant leaks in the cac (small one I repaired with jb weld for now). There is no CEL lights, I did not ask GDE if the tune was factory or not so maybe someone put a yeti or self tune on before? Anything else I can check?


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 Post subject: Re: MPG issues
PostPosted: Wed May 08, 2019 5:34 pm 
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Check engine temperature after the engine is fully warmed up. Do not trust the O.E. engine temperature gauge.

Please use either the Torque Pro app, or an OBDII reader to get an actual temperature measurement.

Cross reference your temperature reading with an infrared temperature gun reading with the laser pointed on top of the thermostat assembly.

The readings - whatever they are - should be the same or close to the same. If they are not the same, either the infrared temperature gun is inaccurate, or more likely the O.E. temperature sending unit is malfunctioning.

If your engine temperature is significantly lower than 180 degrees Fahrenheit, then your engine operating temperature is too low. This will negatively affect fuel efficiency and performance of the engine.


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 Post subject: Re: MPG issues
PostPosted: Wed May 08, 2019 7:01 pm 
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Location: Oregon Coast Dairy Country. Land of stumps, dumps, and "Liquid Pumps"
Don't trust the EVIC unit for specific mileage.
They are consistent, but that's consistently wrong, in most cases.
Do it the old fashioned way, by hand. More of a pita, but always as accurate as your odometer.

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 Post subject: Re: MPG issues
PostPosted: Wed May 08, 2019 7:15 pm 
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I do count by hand, the evic says 25 which doesnt seem to far off at this point. I did just verify that the turbo actuator is indeed working, I am asking GDE if they can confirm that the current tune is a factory tune. I was driving earlier today and when to pass someone, 25-60 pull at about half throttle and got a fair amount of smoke behind me and then a sudden stutter when off throttle that cleared up in a few seconds.


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 Post subject: Re: MPG issues
PostPosted: Wed May 08, 2019 8:53 pm 
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For mixed driving like you state I would say about 24 or maybe a little more as long as not extended idling times. The engine temp is very important. Thats about how far most of the factory EVIC s are off with original size tires. Make sure you drive with the overdrive on and just to confirm I would switch it on and off and watch RPM s to verify switch is functional. The RPM with overdrive on should show about 1650 in fifth gear lockup at 60 mph but you have to go up to about 65 to get lockup then slow back down to 60.even transmission fluid change could help a bit but not a lot but I also would wait for the TC change. It could also be map sensor even if you cleaned it It might be worth replacing

Something is not right with the episode you describe . Another common problem is the turbo inlet hose cracking. I suspect the jb weld may not be working as well as it should or some leak elsewhere like the cpvc puck or hose .

_________________
05 Blu LIM, OME GDE Tbo, wk II 245/75/17, KC Lights, bull bar, 185K H TC
05 Blu Lim, Dayton, GDE HT, 255/75/18 , 200K , H TC
06 Bla Lim, GDE Eco, Destination AT 245/75/17, 151K, H TC
06 D Khaki Lim 112K wkII Eur TC
05 D khaki Lim 145k refurbishing
CRDS: Fumoto, Kennedy Lift , Fan Shroud mod, fuel head, SAMCOS,self TB, 2 Mic filt, Hayden


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 Post subject: Re: MPG issues
PostPosted: Wed May 08, 2019 10:27 pm 
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I am in OD for sure, the black smoke under accell has been an issue since getting it to run. The leak in the cac was tiny, not enough to bleed significant boost, turbo inlet is fine and both cac hoses fine, i'm maybe leaning towards a faulty EGR bleeding off boost. Is it possible to see map pressure from obd2?


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 Post subject: Re: MPG issues
PostPosted: Thu May 09, 2019 1:31 pm 
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timothyd wrote:
I am in OD for sure, the black smoke under accell has been an issue since getting it to run. The leak in the cac was tiny, not enough to bleed significant boost, turbo inlet is fine and both cac hoses fine, i'm maybe leaning towards a faulty EGR bleeding off boost. Is it possible to see map pressure from obd2?

You could install an EGR block off plate to rule out the EGR leaking boost. It needs to be blocked off anyway.
See this thread for full details:> viewtopic.php?p=804565#p804565

Image

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 Post subject: Re: MPG issues
PostPosted: Tue May 14, 2019 3:17 pm 
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Location: San Diego
Not sure if its a common thing or just me, but my speedometer and odometer have always been a little off, underestimating my speed and miles driven. If I calculate using real mileage driven, my mpg improves by about 1.5mpg.

Also tires are a huge factor. When I switched from 70k mile warranty hancooks to some beefier tread coopers, my mpg went down by about 3mpg.

Even driving like a granny, the discrepancy between city and highway can be big. I can do 27-30mpg all highway, but im closer to 23-24mpg combined when i do a little city driving as well.

of course the usual no boost hose leaks, working thermostat, disable egr etc are also factors.

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 Post subject: Re: MPG issues
PostPosted: Fri May 17, 2019 6:21 pm 
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Interesting,
Sorry for the metrics but that is what we are forced to use here.
My kj averages out at approx. 14lt to 100k on our local roads with 80 k speed limit and no real stop start driving at 2000 rpm at 80k.
If I get on the highway I use about 11lt to 100k but the rpm drops to 1750 overdrive on.
Towing 1500kg on the highway its about 17lt to 100k overdrive off.
At the 80k overdrive doesnt seem to change engine rpm.
Temps good , no apparent leaks, egr disabled and map sensor clean.


Any ideas why gears and speed behave as they do?
I would have thought economy at 80 would be better.
Peter

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2006 KJ CRD
Yeti tune
EGR delete
Straight through exhaust
Airtex fuel pump
2 micron filter
2" lift


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 Post subject: Re: MPG issues
PostPosted: Sat May 18, 2019 7:53 am 
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phum wrote:
Interesting,
Sorry for the metrics but that is what we are forced to use here.
My kj averages out at approx. 14lt to 100k on our local roads with 80 k speed limit and no real stop start driving at 2000 rpm at 80k.
If I get on the highway I use about 11lt to 100k but the rpm drops to 1750 overdrive on.
Towing 1500kg on the highway its about 17lt to 100k overdrive off.
At the 80k overdrive doesnt seem to change engine rpm.
Temps good , no apparent leaks, egr disabled and map sensor clean.


Any ideas why gears and speed behave as they do?
I would have thought economy at 80 would be better.
Peter

Sorry, dumb American here who’s too lazy to convert Km to miles. :P

You’ll get the best MPG when the transmission is in 5th gear. And you have to get above 60 mph before it will shift into 5th.
Therefore your best MPG should be in the 63-70 mph range.
Once you get above 80mph, MPG will take a significant hit due to poor aerodynamics.

I typically drive on the highway at 75 mph and get about 26 mpg.
City driving is around 24 mpg

My Jeep is lifted and has tall heavy tires.
My speedo is about 6% slow and my odometer is about 10% slow.

_________________
Bought my '05 CRD on June 2nd '07, used with 29,000 miles.
intake elbow and EGR delete. 5 volt bosch glow plugs
Yeti stage 2 ECU tune. Straight pipe exhaust. DIY intercooler hoses
Provent and modified factory 180F thermostat
Replaced cylinder head (cracked) at 160,000 miles + ARP studs
2.5 inch lift, JBA upper arms, 235-85-16 tires.
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 Post subject: Re: MPG issues
PostPosted: Sat May 18, 2019 5:31 pm 
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I have a new map sensor and an egr blockoff plate on the way, will be installing next week. The tires are 235/70/16's, they might be changing the speedo (*i think I read that these are adjusted with a programmer?) but are indeed 60k mile tires that are traction tires, not at's.


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 Post subject: Re: MPG issues
PostPosted: Sat May 18, 2019 7:27 pm 
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flash7210 wrote:
phum wrote:
Interesting,
Sorry for the metrics but that is what we are forced to use here.
My kj averages out at approx. 14lt to 100k on our local roads with 80 k speed limit and no real stop start driving at 2000 rpm at 80k.
If I get on the highway I use about 11lt to 100k but the rpm drops to 1750 overdrive on.
Towing 1500kg on the highway its about 17lt to 100k overdrive off.
At the 80k overdrive doesnt seem to change engine rpm.
Temps good , no apparent leaks, egr disabled and map sensor clean.


Any ideas why gears and speed behave as they do?
I would have thought economy at 80 would be better.
Peter

Sorry, dumb American here who’s too lazy to convert Km to miles. :P

You’ll get the best MPG when the transmission is in 5th gear. And you have to get above 60 mph before it will shift into 5th.
Therefore your best MPG should be in the 63-70 mph range.
Once you get above 80mph, MPG will take a significant hit due to poor aerodynamics.

I typically drive on the highway at 75 mph and get about 26 mpg.
City driving is around 24 mpg

My Jeep is lifted and has tall heavy tires.
My speedo is about 6% slow and my odometer is about 10% slow.[/quote

Rough conversion
80 is about 50mph
100 60
1500kg 3400lbs
17lts a 100 about 17mpg (not to good)

_________________
2006 KJ CRD
Yeti tune
EGR delete
Straight through exhaust
Airtex fuel pump
2 micron filter
2" lift


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 Post subject: Re: MPG issues
PostPosted: Sun May 19, 2019 9:03 am 
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Location: Jackson,TN
The diameter of a 235/70/16 is about 29 inches depending on specific tire brand etc. . That is about the same as the stock wheel/tire combination. So, though the speedometer and or EVIC is undoubtedly not accurate it should have about the same inaccuracies as they did when new with stock tires and wheels.

_________________
05 Blu LIM, OME GDE Tbo, wk II 245/75/17, KC Lights, bull bar, 185K H TC
05 Blu Lim, Dayton, GDE HT, 255/75/18 , 200K , H TC
06 Bla Lim, GDE Eco, Destination AT 245/75/17, 151K, H TC
06 D Khaki Lim 112K wkII Eur TC
05 D khaki Lim 145k refurbishing
CRDS: Fumoto, Kennedy Lift , Fan Shroud mod, fuel head, SAMCOS,self TB, 2 Mic filt, Hayden


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 Post subject: Re: MPG issues
PostPosted: Sun May 19, 2019 8:53 pm 
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The tires will knock down the mileage a bit. A loss of 1-4mpg is reasonable depending on tire weight and tread pattern.

If you can measure the MAF (mass air flow) at idle with an OBD monitoring tool, that data is useful to determine underlying issues with valvetrain. A new engine is about 18.3 g/s at idle.

What altitude are you at?

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 Post subject: Re: MPG issues
PostPosted: Sun May 19, 2019 10:05 pm 
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One thing I've learned with these little tractors is nothing is consistent. My first one bone stock got 26 mpg highway at 75mph and when simply installing the EHM and ORM including unplugging the MAF sensor I would get 30-32 mpg highway at 75mph. This one I have now with full mods, same tires and the GDE FT Echo Tune will only get, at best 24-26mpg. As for things that can affect fuel economy in general:
1. Timing Belt not set right
2. EGR (needs to go away)
3. Clogged intake from EGR soot
4. Leaking boost from somewhere
5. Dirty air filter
6. leaking head gasket
7. Leaking injector(s)
8. Lift kits
9. Oversized tires
10. Optional fog lights/brush guards
11. Air in fuel
12. Engine not reaching and maintaining operating temperature.

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New at 164K: head gasket, rockers, exhaust valves, ARP head studs, Injectors, 7v steel glow plugs, water pump, timing everything, serpentine everything,


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 Post subject: Re: MPG issues
PostPosted: Mon May 20, 2019 2:37 am 
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GreenDieselEngineering wrote:
The tires will knock down the mileage a bit. A loss of 1-4mpg is reasonable depending on tire weight and tread pattern.

If you can measure the MAF (mass air flow) at idle with an OBD monitoring tool, that data is useful to determine underlying issues with valvetrain. A new engine is about 18.3 g/s at idle.

What altitude are you at?






If the question is for me never more than 500ft mostly 30ft.
Can you reprogram the trans computer to change shift points?
Peter

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Yeti tune
EGR delete
Straight through exhaust
Airtex fuel pump
2 micron filter
2" lift


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 Post subject: Re: MPG issues
PostPosted: Mon May 20, 2019 8:28 pm 
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I'm at 360ft, I'm going to buy an obd reader and check on the sensors for sure. Just put in the new map sensor with no change. I will be doing the EGR plate tomorrow and see if that changes anything. What would most consider excessive black smoke? It only does it either at a dig or at medium speed with 75%+ throttle, and its nothing like the "rolling coal" clouds, just an obvious amount of black smoke in a trail behind.

Correct me if I am wrong, black smoke is too much fuel for the combustion to complete properly, i.e. not enough air or some other combustion factor. So I would assume that since the use of the map is to measure boost and the maf for total air, the fuel trim should coincide correctly if these sensors are working correctly, it would not be a boost leak or lack of air? That would lead me to believe either timing, over fueling injector, or a leak of compression. I'm going to verify my timing with the locking pins, testing the injectors is expensive so i'm not going to jump on that, or potentially a bad rocker leaking compression?

A side note, I definitely have air coming into the fuel, I can start it and just let it run a few minutes and pull out air from the filter, what are the likely places for air to be getting in? (Gen 2 filter head) I have also read that this can cause the same issue, messes with the fuel pumps timing.


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 Post subject: Re: MPG issues
PostPosted: Tue May 21, 2019 1:20 am 
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Location: Oregon Coast Dairy Country. Land of stumps, dumps, and "Liquid Pumps"
Timing variation may be the least of your worries if you have air ingress into your diesel.

Rapid wear of the high pressure pump, and even internal injector parts is far more expensive and problematic.

check this

https://www.hydraulicspneumatics.com/maintenance/cavitation-or-aeration-you-can-hear-difference

Due to the engine running in close proximity, the "hearing the difference" part isn't really applicable, but the internal damage is still being done. The critical tolerances in a fuel injection system kind of run at the edge of material strength anyway, but when air is present at the point where fluid pressures change dramatically, it causes the fuel to blast microscopic craters into metals, and vibration that causes breakdown of molecular structure in critical pump parts, bearing journals, valve seats, and calibrated passages within the fuel (hydraulic) system.

So running poorly may be the symptom that you notice, but it's really the least of your worries, and this shows the main reason why an in-tank lift pump is not just a patch as other fixes, but really the best long term fix, and insurance against having expensive failures in the future.

_________________
'06 Lbrty Sprt CRD 150K

Sasquatch
DSS Turbo
CAT-elimntr
Weeks Stg1&2 EGRfix
PV-200
BLING
vent gauges

IDParts
head
cams
rockers
Timing set
ARP studs
eTn1 GX2123 5v GPs

YETI Custom Tune
Flowmaster 8325508
Carter P76611M
GM 12611872
Hayden 2986
GM 15976889
PATC Custom Billet
2010 Ram Hemi Trans
Sonnax 44957
Transgo kit
Cooper 51770


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 Post subject: Re: MPG issues
PostPosted: Tue May 21, 2019 11:44 am 
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GordnadoCRD wrote:
Timing variation may be the least of your worries if you have air ingress into your diesel.
Rapid wear of the high pressure pump, and even internal injector parts is far more expensive and problematic.
check this
https://www.hydraulicspneumatics.com/maintenance/cavitation-or-aeration-you-can-hear-difference
Due to the engine running in close proximity, the "hearing the difference" part isn't really applicable, but the internal damage is still being done. The critical tolerances in a fuel injection system kind of run at the edge of material strength anyway, but when air is present at the point where fluid pressures change dramatically, it causes the fuel to blast microscopic craters into metals, and vibration that causes breakdown of molecular structure in critical pump parts, bearing journals, valve seats, and calibrated passages within the fuel (hydraulic) system.
So running poorly may be the symptom that you notice, but it's really the least of your worries, and this shows the main reason why an in-tank lift pump is not just a patch as other fixes, but really the best long term fix, and insurance against having expensive failures in the future.

Good article!
Picked up on this statement below which might lead one to believe it is best not to let the fuel level in fuel tank get so low as to allow air ingestion or infusion into the suction the OEM suction pipe or the suction inlet of an intank fuel pump if so equipped.
Probably a very good and safe practice to always refill fuel tank whenever it drops below the 1/4 level when possible.

Hydraulics & Pneumatics wrote:
Finally, the fluid level in the reservoir should never drop to more than 2 in. above the suction line inlet. If so, a vortex can form—much like when draining a bathtub. This introduces air into the suction line, resulting in aeration.

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Proud Supporting Vendor of LOST
05 Jeep Liberty CRD Limited :JEEPIN:

Ironman Springs/Bilstein's
Yeti Stg4 MaxTune
Weeks ElbowKit/BatteryTray
NO FCV/EGR
Samcos/ProVent
SunCoast/Transgo
Carter Intank-pump
2mic.Sec.Fuel Filter
Flowmaster/NOcat
V6 Airbox
GM11 blade fan/NAPA HDclutch
Ironrock Trilink
Dodge Cummins, 5"exh. Viair, Huge K&N


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 Post subject: Re: MPG issues
PostPosted: Wed May 22, 2019 6:03 am 
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phum wrote:
GreenDieselEngineering wrote:
The tires will knock down the mileage a bit. A loss of 1-4mpg is reasonable depending on tire weight and tread pattern.

If you can measure the MAF (mass air flow) at idle with an OBD monitoring tool, that data is useful to determine underlying issues with valvetrain. A new engine is about 18.3 g/s at idle.

What altitude are you at?






If the question is for me never more than 500ft mostly 30ft.
Can you reprogram the trans computer to change shift points?
Peter


Yes we have transmission tuning available.

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