Poor mpg 05 crd

biggreenjeep · **Joined:** Mon Aug 29, 2016 10:55 am **Posts:** 22

Ok so i bought an 05 crd with 60k miles a few months ago for the sole purpose of having a 4wd suv that gets good mpg. I have yet to see over 21 mpg. Its got 4 new injectors (long and expensive story there). The weeks elbow kit, straight pipe from turbo back, clean stock air filter, and a fresh oil change. 2 weeks ago i flashed the ecu with the 808 mild tune that is on the diy ecu flash thread. I just too it for a 54 mile highway trip and stopped to top it off. She took 3.1 gallons to do 54 miles at 60-65 mph under very light throttle. I live at about 2200 feet above sea level and it was 45 degrees out. It was fully warmed up when i filled up before i left. That trip i netted 18 mpg. Now this was also on off road diesel. Ive fun both on and off road and never notice more than a 1mpg difference which could come down to driving stle more than the fuel. Ive read thru alot of threads on here and see people getting far better mpg than this. Whatelse could he causing the poopy mileage?

jws84_02 · **Posted:** Sun Nov 27, 2016 2:08 pm

Possibly breaks sticking, bad thermostat. What's the story behind 4 new injectors?

mass-hole · **Posted:** Sun Nov 27, 2016 3:12 pm

Yeah if your temp gauge is not getting to like 1 tick of center then it's probably a bad tstat. I bought my jeep with 42k and its thermostat was already dead. Everytime I would coast downhill in the winter the engine would cool off and I would loose cabin heat, then it would come back as I went back uphill.

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geordi · **Posted:** Sun Nov 27, 2016 3:30 pm

Thermostat first, that is likely a big part of the problem if it is not getting to dead center or just a hair left.

I wouldn't admit using off-road diesel, but that is fine if you truly are off-road with it. However: It is exactly the same fuel in 95+% of cases, b/c it is cheaper / easier for the rack to just stock one product for all the middle-distillate customers. Tanks full of home heating oil are all filled with red dye winterized diesel... Which is exactly what you put in your tank pretty much everywhere in the country right now. Winter diesel is everywhere b/c that is what the suppliers stock starting probably in September.

You can find out about the brakes with a simple infrared temp gun. Go for a drive, and then get out and shoot the discs on all four wheels. They should all be within a hundred degrees of each other, the front will probably be about 200 hotter than the back. But if any are WAY hotter - you have found your culprit.

Taking the brakes apart and lubing the slide pins is never a bad idea - I usually use synthetic axle grease (blue bear snot) and liberally apply it on anything that is supposed to move.

biggreenjeep · **Joined:** Mon Aug 29, 2016 10:55 am **Posts:** 22

Judging by this i will first go after the thermostat. It runs at about the 1/4 mark. I hate dummy gauges. I would much rather have a real temp gauge. Im not too worried about talking about running offroad on here. If someone truely has a bug up their booty and wants to try and figure out exactly who i am and hunt me down and have a DOT cop dip my tank then they've got bigger issues than me. I run it bc its 70 cents a gallon cheaper where i live and im poor. I had a lean condition where i was blowing white smoke and after entirely too long of fighting with it and eliminating all other possibilities i sent my injectors out to oregon diesel and they bench tested them. 2 were bad, and 2 were really bad. Im assuimg theyre bad due to sitting for so long and a cheap fuel filter. I paid 380/injector for remans from them.

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geordi · **Posted:** Sun Nov 27, 2016 8:17 pm

White smoke is coolant. Black smoke is too much fuel, blue smoke / really stinky grey smoke is burning oil.

A lean condition is called diesel combustion. Lean is good, you WANT a diesel to run lean that is how it works. When the cylinder runs out of air and still has fuel, you have black smoke / wasted fuel and WAY HOT cylinder temps. You don't want this. When the cylinder runs out of fuel and still has air, that is what you want. The limitation will be available power, but you can compensate in the tune for that by increasing the fueling. When you start to get smoke or EGT is too high, increase the boost. This is how diesels are programmed. There are of course limits of what the engine will survive, but you want it lean-burning all the time.

Mountainman · **Posted:** Sun Nov 27, 2016 11:18 pm

Pull your viscous heater relay. That sucker kills mileage. Expect a cooler engine with bad thermostat though. I would ditch the stock thermostat and buy one of Jeff's.

papaindigo · **Posted:** Mon Nov 28, 2016 2:34 pm

biggreenjeep - it's not a dummy gauge rather it simply lacks degree marks. See http://www.greendieselengineering.com/j ... st/19.page for a breakdown of what marks mean in degrees.

biggreenjeep · **Joined:** Mon Aug 29, 2016 10:55 am **Posts:** 22

Mountainman wrote:

Pull your viscous heater relay. That sucker kills mileage. Expect a cooler engine with bad thermostat though. I would ditch the stock thermostat and buy one of Jeff's.

Who is this jeff you speak of? I just looked up new ones. Are they made if diamonds or something? Wtf. I come from the land of 3 dollar stant thermostats that last a life time.

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blk05liberty · **Posted:** Mon Nov 28, 2016 4:09 pm

oem are spendy, but that's just the tip of the iceberg lol :SOMBRERO:

flash7210 · **Posted:** Mon Nov 28, 2016 4:10 pm

biggreenjeep wrote:

Mountainman wrote:

Pull your viscous heater relay. That sucker kills mileage. Expect a cooler engine with bad thermostat though. I would ditch the stock thermostat and buy one of Jeff's.

Who is this jeff you speak of? I just looked up new ones. Are they made if diamonds or something? Wtf. I come from the land of 3 dollar stant thermostats that last a life time.

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Jeff goes by the name of TURBO-DIESEL-FREAK. He posted in your other thread and his contact info is in his signature block.

The factory thermostat is sealed up inside a housing. The entire housing must be purchased. Hence why its so expensive.
If you do a forum search for "thermostat" you'll find lots and lots and lots of info (probably too much info). Plus alternatives to the factory thermostat.

biggreenjeep · **Joined:** Mon Aug 29, 2016 10:55 am **Posts:** 22

flash7210 wrote:

biggreenjeep wrote:

Mountainman wrote:

Pull your viscous heater relay. That sucker kills mileage. Expect a cooler engine with bad thermostat though. I would ditch the stock thermostat and buy one of Jeff's.

Who is this jeff you speak of? I just looked up new ones. Are they made if diamonds or something? Wtf. I come from the land of 3 dollar stant thermostats that last a life time.

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Jeff goes by the name of TURBO-DIESEL-FREAK. He posted in your other thread and his contact info is in his signature block.

The factory thermostat is sealed up inside a housing. The entire housing must be purchased. Hence why its so expensive.
If you do a forum search for "thermostat" you'll find lots and lots and lots of info (probably too much info). Plus alternatives to the factory thermostat.

Thanks. Not sure how i managed to get 2 threads started

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dennyb · **Joined:** Wed Aug 13, 2014 4:27 pm **Posts:** 110

I've ran my homemade for 2 years now. Put one on friends CRD too.

viewtopic.php?f=5&t=80231&p=852686&hilit=Junkyard+thermostat#p852686

minisub · **Posted:** Mon Nov 28, 2016 8:25 pm

I recently replaced my calipers and picked up an honest 4 mpg. I knew the pistons were a little sticky, but they never felt like they were dragging so much to make that much difference. I wish I had done it so much sooner.

tvince0913 · **Posted:** Mon Mar 27, 2017 1:06 pm

Minisub, which calipers did you go with when you replaced? The OEM ones from IDParts? I have heard people say good things about the NAPA remans. I just greased up my caliper slide pins and it didn't seem to make any difference for my mpg. I suspect bad or dragging brake calipers now, just wondering what people usually go with for replacements.

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Poor mpg 05 crd

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