Hello all, I have a 216K mile 4.0 AWD extended van, and I recently went to go get a trailer. 1300 mile round trip, a bit of moderately hilly terrain followed by flat lands. Drive there (no trailer) was 70mph average speed, 15mpg according to the dash thing (math proved that damn near correct).

On the way back, with the empty 1000lb 6x12 enclosed trailer, which is 9 feet tall btw, fuel economy was 11mpg. Towing was done at 60mpg max, in D.

Is this normal? Van has 225/75/15 tires if that is important (which it is, I'm sure). Plugs and wires and thermostat and o2 sensor are all new, with less than 6k miles on everything. If there is anything I can check, that would be great, I got kinda sick of buying fuel lol... Any help would be appreciated. Thanks!

 

what year? the 96 on have sequential fuel injection which gets higher mileage in the 4L
i can squeeze 22 mpg out of mine on summer gas at 55mph on the flat freeway with no headwind on cruise control.

11mpg is in the normal range for a high wind resistance trailer, weight doesn't become a factor until major hills or intown stop and go.

i got 8>14 towing a 4000 lb travel trailer with mine, towed at 50 to 55 on the freeway and good roads.
hills, headwind and driving faster than 50>55 kill fuel mileage in these Aeros towing

slow down, enjoy the country and save some gas.

 

I have done the same journey with the same vehicle and tent trailer (1800lbs fully loaded) for 8 years running at virtually the same time each year, and so I've experimented with my driving and the style of driving almost each time. It's 344kms one way and about 150k of it is extremely twisty, mountainous roads.

My journey is about 4.5 - 5 hours depending on how heavy my foot is. Also factor in a stop for lunch. If I'm very careful (and I had the transmission fluid flushed, and new oil and a tuneup, and allowing it to creep over the speed limit down hills, letting it die uphill) I can do it on 3/4 of a tank. If I'm semi careful (speed limit or less, letting it die up the big hills but no tuneup or real concessions to economy), I'm on fumes upon arrival. If I floor it on the hills and generally try to get there as soon as possible without any regard for economy (and that year I didn't have it tuned before I went - big factor, and I went about 10k over the limit at most instances) I must fill up about 50kms short of my destination as the van is below the E and there isn't a station for miles.

There was once one time when my vacuum hoses came off and I had to do it on 2 tankfuls of gas 1 way!! But we won't factor that one in..that'd probably be 5mpg!

So, to figure it out....

1 tank = 21 gallons. = 79 litres. And assuming gas is $1 per litre each...Last year I repeated the Very Careful scenario, (don't forget my van now has 300K plus, so the economy should be slowly decreasing as it ages) and I got nearly 18mpg. It takes me 1/2 an hour longer because I really let it slow down on the hills but more but a big savings in the pocketbook

The secret? 2 things...

1) A Tachometer - you can be going up a hill at a lower rpm and you save a lot in economy if you ease up on the throttle a little. You can mash it down and go nowhere, and do nothing but use up more fuel. You can do it by ear, but I find a needle is more of a reminder to me.

2) I packed very lightly last year - a lot of the stuff we shared with others so my van wasn't as weighted down as in other years.

Also, I've noticed that my economy has ramped up tremendously since I put a Transmission cooler in. I think 18mpg is the best I can hope for in that scenario. Which isn't bad, really.

By the way, the Very Careful scenario is about what Mileage I get as a general rule around town, no trailer, largely unladen. It's normally why I use my car - an NX 2000 around town because doing that duty gets about 28mpg, roughly double the mileage of the Aero.

 

It's a 94... and my driving style is pretty much set the cruise at 55 and watch literally everything pass me. And, I have the digital dash complete with fuel economy computer, which is kind of depressing when I see 7mpg climbing hills...

 

Oh, and I know this is off topic, but...

When hooking up the trailer, I drove approximately 5 hours with all the lights going with no issues. On that fifth hour, the fuse for the van's running lights blew. After replacing the fuse, any replacement blew after only lasting a half hour or so. Any idea what would cause this, or how to start in diagnosis? Wire for the running lights is directly wired to the van, no relay. Thanks...

 

Your 225/75/15 tires are about 6% taller than the stock size of 215/75/14, so at a given speed, the speedometer will be reading about 6% lower than actual speed, and the odometer will also register that much less. (small difference, I know)

Given all else being equal, the drag power increases with the cube of the vehicle speed. That you're towing a large rectangular box has a multiplicative factor. So a small increase in speed will require a lot more power, and thus fuel consumption rate, to keep up.

A variation on that would be the engine and drivetrain performance. Since you're going 55, a relatively low speed, the drag should not be nearly as high as going 65. But if you're doing it in D instead of OD, then the engine still works a lot harder. (Of course, I don't know how well the 4L engine can tow something like that i OD, or if the transmission will survive.)

As for your running lights, it's possible that the circuit may have overheated, and even caused a short. Does it still blow the fuse with the trailer's lights disconnected? The Aerostar has weak wiring for lights, like a lot of Ford cars. I would consider installing relays and heavier wires to power the trailer lights.

 

forgot to note that the Aero A4LD auto tranny will not last long trailer pulling without adding an aux. tranny cooler.
the largest you can fit in front of the radiator/ a/c condensor.
plate and fin only
i fit a 12"x12" x 3/4" plate fin in mine and bypassed the radiator end tank cooler. the radiator coolant pumps too much heat into the tranny on long hard hill pulls on hot days.
the big plate fin out in front cools it well. took care of all my burnt tranny ATF fluid and ATF puke over issues. no more stranded along the road 100 miles from no where 3 qts low and used the last of the ATF spares.

skimp on tranny cooler and expect a $3000 tranny bill to get the rig home. highway vultures

 

Well, now I know that I will keep it at 55 on my trip back down with a loaded trailer... and as for the wiring, no, the fuse does not blow with the trailer disconnected, and with the trailer connected it will work fine for a bit, get dim for a bit, then the fuse will blow. And installing relays sounds like something I will do, any idea as for the correct size fuse to use in the power wire?

 

What size is the fuse in there now? Since it takes some time to blow, it must be just marginal, so I would get something 25-50% bigger.

 

Fuse that was in there that kept blowing was a 15amp, I replaced it with a 20amp which blew after about 45 minutes... got a 25amp in right now, and so far during my 20 or so minute testing sessions, it stayed intact. However, something that I have noticed, the LED taillights on the trailer, normally the four center LED's are lit. At times, the right taillight onyl has two LED's lit, and all the lights get dimmer like normally happens right before the fuse blows. Is there a way short of outright replacing that taillight? Like, is there a way to measure the resistance of the taillight so I cna determine whether it is the light or the wiring that needs replaced?

Sorry for all the nonsensical questions, jsut hoping to make a completely worry-free 1300 mile trip in a week. Thanks!

 

It sounds like you may have a short in that trailer light; 20+ amps draw is way too high for marker lights.

To check out the wiring harness, get a continuity tester, like a DMM with the continuity function. If possible, disconnect the LED assembly from the end of the wiring and check the wires and the LED assembly individually for electrical shorts. Also check between the wires and the vehicle frame.

 

I would put in a relay. The fuse in the circuit powered by the relay would be dependent upon the gauge of the wire. It does no good to put in a fuse if the insulation would melt before the fuse blew. You are risking that scenario when you up-size from the factory recommended fuse.
The mileage is as all above noted: Lead foot == empty wallet. I drove from GA to CA in Dec-Jan, and found that mileage in a 3.0 Mariner could vary from 21mpg to 28mpg, based on by-the-tank measurements of consumption/miles traveled. If someone else drove the limit of 75mph, the mileage fell off. If one drove 65-70 depending on the topography, let it slow on the up-grade, and let it slide on the downgrade, the mileage went up 20-30%, more or less.
A friends extended A* got around 18-20 all the time with a 4.0/A4LD. When the fuel pressure regulator jammed, the mileage literally fell to one half, i.e., 9-10mpg. They were surely proud of that regulator part, as they wanted quite a bit for the replacement. Around $200, IIRc.
tom

 

probably worn through trailer wiring insulation intermittently hitting the chassis frame ground.
they use the cheapest wire possible on trailers.
time to rewire
use marine grade tinned copper with the tough insulation
has a USCG rating approval, expensive but never have to do again.

sealed LED lights only.

 

regarding gas mileage, ive been keeping careful track of mine since august 09

Gas Mileage

 

I gotta say MPG is why I had to get rid of my Aero and find another daily driver. I bought a '93 Suburban for hauling/towing and a '95 Escort wagon rebuilder ($400) for commuting. The 'burb only comes out once or twice a month. At $3.25/gal I'm saving about $700 a year in gas and this will only get better as prices go up.