Lack of power and high fuel usage while towing

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JBHorne

JBHorne

Joined
Aug 14, 2008
Messages
1,369
Location
Chandler, AZ
This weekend we took a camping trip and pulled a 3000 lb camping trailer. Driving on flat highways at 60 mph the vehicle wanted to hold 3rd/4th gear at 4k RPMs. I averaged 6mpg the whole way and burned four tanks of gas on a 450 mi trip. My typical fuel economy is 10-12mph. It felt as if I was towing a much heavier trailer. Downhill was fine, so I know it wasn't a trailer brake issue. Every time the vehicle tried to shift into 5th gear it would immediately down shift back to 4th to get power. No codes or check engine light. No weird idle or other odd sounds. Didn't feel like a transmission issue - honestly felt as if I was either towing a MUCH heavier trailer or lost 100+ horsepower. If I put my foot down it would take a good minute to get from 60 to 70mph.

Of interesting note it was 80* outside and my AIT (per ScanGauge) was 120*. Is a 40* rise for intake temp normal? Also, AFR was consistently low - 11.2 to 13. So, I thought it could be an intake issue so I went to Walmart and got that MAF sensor cleaner and manifold cleaner and cleaned both. Didn't help. Oh, and filter is brand new. I'm at 94k miles.

Any ideas? My LC is lifted with 34" tires, ARB bumpers front and rear, skid plates, winch, sliders, etc. What are others with similar modifed setups getting for highway fuel economy, both normal and towing (and what weight trailer)?

Thanks guys (and gals)!
 
I tow a 28' airstream and I agree that your experience seems quite out of normal. On level roads, I am almost always in 5th, and can grab 6th without problem. But generally in 4th and 5th depending on wind and inclination. I'm also on 33s (33.2" per spec), but without armor.

How does she feel driving without something in tow?

Assuming something is wrong...

It's odd to lose that much power, yet not getting a check engine light, and everything seems to otherwise run normal I'd take a look at the catalytic converters underneath. Possible that they are plugged and the engine is experiencing a ton of backpressure. If they are failed, they would be trapping a bunch of heat, and with enough time look discolored and oxidized.
 
JBHorne said:
This weekend we took a camping trip and pulled a 3000 lb camping trailer. Driving on flat highways at 60 mph the vehicle wanted to hold 3rd/4th gear at 4k RPMs. I averaged 6mpg the whole way and burned four tanks of gas on a 450 mi trip. My typical fuel economy is 10-12mph. It felt as if I was towing a much heavier trailer. Downhill was fine, so I know it wasn't a trailer brake issue. Every time the vehicle tried to shift into 5th gear it would immediately down shift back to 4th to get power. No codes or check engine light. No weird idle or other odd sounds. Didn't feel like a transmission issue - honestly felt as if I was either towing a MUCH heavier trailer or lost 100+ horsepower. If I put my foot down it would take a good minute to get from 60 to 70mph.

Of interesting note it was 80* outside and my AIT (per ScanGauge) was 120*. Is a 40* rise for intake temp normal? Also, AFR was consistently low - 11.2 to 13. So, I thought it could be an intake issue so I went to Walmart and got that MAF sensor cleaner and manifold cleaner and cleaned both. Didn't help. Oh, and filter is brand new. I'm at 94k miles.

Any ideas? My LC is lifted with 34" tires, ARB bumpers front and rear, skid plates, winch, sliders, etc. What are others with similar modifed setups getting for highway fuel economy, both normal and towing (and what weight trailer)?

Thanks guys (and gals)!
Click to expand...

What is your best way with all that armor and bumpers 734 inch tires?
 
SWUtah said:
What's your beast weigh with all that armor? Loaded I bet your over 8k lbs
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I guess around 7800. Probably added 1k.
 
I realize you may not want to hear it, but I believe the owners manual for the 6-speed models says to use "manual" shift mode and set it to S4 thereby limiting the automatic transmission range to 4th gear. (On my 8-speed it is S6 but the same idea.) And that is for a stock truck without all the add ons. Also, I think they expect you to keep your speed at about 65MPH. The Land Cruisers are probably near best in class for towing but they are not pickup trucks or diesels. You may want to re-gear your truck.

I tow a 6,000#, 27' travel trailer around Colorado. When I hit a long climb (often 5-6% grades for a few miles) I drop it into 2nd or 3rd and run it at about 3K RPM which, I believe, is about the sweet spot in the torque curve. I'm getting about 10-11 MPG on average but I don't push it over 65 nor attempt quick acceleration outside of needing to merge onto a freeway.

I don't have a lot of armor but loaded up my truck weighs ~6800.
 
Dan Higgins said:
I realize you may not want to hear it, but I believe the owners manual for the 6-speed models says to use "manual" shift mode and set it to S4 thereby limiting the automatic transmission range to 4th gear. (On my 8-speed it is S6 but the same idea.) And that is for a stock truck without all the add ons. Also, I think they expect you to keep your speed at about 65MPH. The Land Cruisers are probably near best in class for towing but they are not pickup trucks or diesels. You may want to re-gear your truck.
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I've thought about regearing. Wonder if anyone else has. Even at 65 we were in 3rd gear pulling 4k RPMs and burning 6 mpg. I still don't think that's normal.
 
@JBHorne When you say you normally get 10-12mpg you mean empty without the trailer or you usually get that with the trailer and this time it just really sucked?
 
6mpg? Surely something is off.

Dragging trailer brakes???
 
tabraha said:
@JBHorne When you say you normally get 10-12mpg you mean empty without the trailer or you usually get that with the trailer and this time it just really sucked?
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Without.
 
fireball said:
6mpg? Surely something is off.

Dragging trailer brakes???
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That was my thought but downhill even slightly was fine. Under 20mph the brake force was minimal when taking foot off the accelerator. And when engaging the brake controller the brake force was noticeable.
 
tabraha said:
@JBHorne When you say you normally get 10-12mpg you mean empty without the trailer or you usually get that with the trailer and this time it just really sucked?
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Sorry. I was not clear. That is average when towing. Of course, when going up those long grades it drops to about 6. :( When not towing I get around 15-16 on average.
 
Dan Higgins said:
Sorry. I was not clear. That is average when towing. Of course, when going up those long grades it drops to about 6. :( When not towing I get around 15-16 on average.
Click to expand...

So 100 miles on a tank is normal when towing 3k lbs?
 
Not at all. I'm towing 6,000 lbs. Did it from Buena Vista, CO to my home near Denver last weekend. 124 miles. Probably 20 miles of 6% climbs and about 40 miles of headwinds and crosswinds. Used about half a tank. Now I am a patient driver usually staying about 60 mph on the flats on these 2-lane highways with cross winds. But 100 miles on a tank? No way. Maybe if I was accelerating up the climbs like a mad man and trying to go 80 on the 65 MPH highway. (Speed can make a big difference but that is more about air resistance than weight.)
 
What does your camping trailer look like? Even if it had the aero of a brick, I can't image that it would have more frontal area and drag than a full travel trailer. Your LC is quite outfitted so I imagine the aero is not good with that either?

I likewise average 10-11 mpg going 55-65 mpg when towing. My trailer is ~6500lb.
 
Could tire under-inflation be contributing to the issue? Totally guessing here. If it were brakes, you would have smelled it after that long, not to mention that hot. I keep my trailer tires at the max (50 PSI). My 285/65 KO2 E-rated tires at a cold PSI of 43 front, 45 rear when towing or maybe a smidge higher in the rear. (Though Gaijin would scold me for over-inflating in the rear. He would probably say that I should keep them at 42 all the time.)

Does your model year have the fuel consumption info screens? Something does seem way off but my LC is not as heavy as yours. (I have have Slee sliders and a fairly heavy Gobi roof rack but only stock bumpers.)
 
BTW, JB, there is another thread on the forum that may be of interest to you. A number of people with towing experience have weighed in on that thread. They may have some thoughts on what is going on - or at least additional experience.

Towing with a 200-series Toyota Land Cruiser
 
JBHorne said:
I guess around 7800. Probably added 1k.
Click to expand...

Just to ensure you're working off of good info, a 08-15 LC weighs something like 5800-5900 lbs stock. +1k of bumpers, sliders, etc. is already hugely generous; remember that GVWR on these trucks is 7385 lbs, so I doubt you're that far over GVWR even with people.

A thought: do these trucks have fuel filters that need maintenance/replacement over time?
 
Bumpers a few hundred, big tires additional 200lbs, wildcard is people and luggage? I weigh 240, wife 120? Agree trailer brakes dragging. I change the fuel filter on my hundred series at 120,000 miles still not a requirement Toyota Lexus don't even mention changing the fuel filter
 
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