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Fuel mileage for a lifted WD21 with M/Ts


JamesRich
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What kind of fuel mileage are you guys with WD21 with 31" mud tires getting? I have changed everything that can be changed as for as tuneup goes including O2, I have almost perfectly even 180psi compression per cylinder so the motor is not shot (only has 108K on the vehicle) The truck came with 31s so the odometer is right, I checked it with my GPS.

Back and forth to work 55mph and only 4 miles so it hardly has time to warm up, I average 15mpg. The first highway trip I took in it on the interstate with the cruse set on 70mph I got barely 13mpg! I know these M/Ts are heavy but I didn't think it would get worse on the highway. I know when this model came out the speed limit was 55 so I guess the motor was tuned for this speed and rpm. My next trip I will take hwy 190 instead of I10 to see if the lower speed makes a difference.

James

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Commuting to work in town, 45 mph street with stoplights, 7 miles one way and running various errands got me 15mpg when I filled up yesterday. Yeah the gas mileage is barely acceptable stock so when you lift, etc it just drops...

 

B

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I have a lifted wd21 about 300 lbs of gear, 80lbs rockrails winch and Arb Bumper and steel rear bumper. I really notice the sluggishness after adding all that weight. I also have headers,32in Cooper MTs, 5 speed trans, and 2 open diffs (Arb lockers disengaged). I think I have done about every so called gas saving mod and I am getting average 17mpg on the freeway. One time I pulled a trailer full of camping gear uphill and got a whopping 10mpg.

 

Mark

Edited by msavides
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I used to get great mpg on 235's going 55 on a 3 hour trip....but city driving usually got me 15/16mpg MAX...now with 33's, steel bumper, gear, and rock sliders....its probably around 12mpg and 14 highway (although it really hates highway except on the rare occasion that its happy...)

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My average of 15 in town I'm not complaining about it's the 13 on the highway thats getting me. So no one else gets worse mileage on the highway? It should do better on the highway. My motor is freshly tuned up, new fuel and air filters but It might be my exhaust thats killing me in the higher rpms. I see alot of y'all have headers, all the exhaust on my truck is still stock,looks like original converter too. It doesn't seem to be restricted sitting still with a vacuum gauge. I don't want to start breaking bolts right now because hunting season is about to start. I guess that will be another project for the summer.

James

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What about your o2 sensor? Mine didn't throw a code but it sure as hell made my mileage crappy.

O2 sensor too, $130 direct replacement from rock auto. I have never had a code other than the normal one. I think it's 55 that means everything is functioning normal.

 

On the Hwy I avg 20 - 21MPG

Around town is more like 17

Damn with your monster rig? You must have someone helping you push it! Now I'm convinced it's my exhaust, all you guys with the higher fuel mileage have headers.

James

Edited by JamesRich
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Damn with your monster rig? You must have someone helping you push it! Now I'm convinced it's my exhaust, all you guys with the higher fuel mileage have headers.

James

 

Lol.. yup. the 3.0 does well.

The headers and 2.5" exhaust helps quite a bit. make sure your running good spark plugs, and that you're on top of the general maint. stuff. Running A/T's helps as well. with the coming overhaul of my truck i'm expecting to lose a little mileage.

 

I strongly recommend getting Thorleys. DT doesn't have any more and neither do I but we can get a group buy together and I can have a batch made.

Edited by SteeevO
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I strongly recommend getting Thorleys. DT doesn't have any more and neither do I but we can get a group buy together and I can have a batch made.

 

So how much we talking about for a set if you have some made and how long? I'm not in a hurry because I don't want to touch anything on the exhaust until after hunting season. I know I will break some bolts and don't want to put the truck down when I need it most. Then I'll be hunting on a little two wheel drive honda recon!

 

Another question for y'all. Where do y'all get a replacement ECU coolant temp sensor? I tested mine and it's out of range. That could be some of my fuel mileage problem. I called Oreilly and the idiot I talked to said they didn't even have a listing. (what he meant was he couldn't find it) I called the closest auto zone and no one would answer the phone. On the way to the shooting range today I stopped at a auto zone and the guy behind the counter started looking it up, then answered the phone and walked to another computer and started looking something up for someone else while I stood there waiting. After 5 minutes I told him where he could go and walked out thinking I'm batting a thousand today!

I looked on rock auto but I'm not sure if I'm looking at the gauge sensor or the sensor for the ECU. Anyone have a part number from Rock auto?

James

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you can hit up any mom and pop exhaust shop and replace the cat with a highflow cat, 2.25-2.5 tubing and a nice flowing exhaust--dynomax or flowmasters

 

autozone duralast pn: SU401

for coolant temp sensor

 

rock auto

BECK/ARNLEY Part # 1580134

for coolant temp sensor

Edited by Cuong Nguyen
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you can hit up any mom and pop exhaust shop and replace the cat with a highflow cat, 2.25-2.5 tubing and a nice flowing exhaust--dynomax or flowmasters

 

autozone duralast pn: SU401

for coolant temp sensor

 

rock auto

BECK/ARNLEY Part # 1580134

for coolant temp sensor

Thanks Man! Thats what I needed. So I was looking at the right one at rock auto. I will hit auto zone first. With the part number I won't have to wait or wonder if they will get me the right part.

As for the exhaust, I know a shop that will cut it all off and just put a turn down if I want so I don't know if I will keep a converter. Thinking of going with maybe a stock muffler for a V8. I want it to flow better but I want it to be quiet for sneaking around in the woods. I put a dynomax super turbo on a V8 once and it was so quiet it sounded stock. I might look into one of those also.

James

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So how much we talking about for a set if you have some made and how long? I'm not in a hurry because I don't want to touch anything on the exhaust until after hunting season. I know I will break some bolts and don't want to put the truck down when I need it most. Then I'll be hunting on a little two wheel drive honda recon!....

 

There is actually one set of DT headers left for pre '90 3.0 v6 pathfinders.

but prices are as follows:

DTH-464-1 | 416.95 | pre '90 V6

DTH-464-2 | 403.95 | 90+ 3.0 V6

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James, I found the sensor on RockAuto, it's under the cooling category, click on "coolant temperature sensor."

 

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Thanks Kingman, I got one at my local autozone. Now if things could chill at work I could put it on the truck. Yesterday I worked 6am to 7pm, good money but no life!

James

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One more thing on the temp sensor. When I tested the wiring harness the FSM said I should have approximately 5V with the key on, I had 4.1V. I checked the pin at the computer and it has the exact same voltage so it's not resistance in the wire. I guess 4.1V could be approximately 5V. Anyone else check they reference voltage, and what did you get?

This truck could seriously use some ground cables. I put a set on my Titan because of resistance problems like this. If I check impedance between the negative battery post and the intake I get 1.5 oms resistance. I will have to make up a set of ground cables to put on here. I'm thinking one from the negative post on battery to the fender. From fender to intake. Maybe intake to TBS. Fender to alternator. I may just get a little happy and ground everything till I run out of wire.

James

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What tranny does your's have? If auto, you probably have the 3speed since it is an 87, that might be the difference. 88+ had an overdrive gear, that could be the reason your highway milage suffers. :shrug:

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