I know it's been discussed before

[ergibbs]

And I've searched through the threads, but I have to ask, anyway. 91 Eddie Bauer Explorer. Tune up with new plugs, filters, etc. last October and purrs like a kitten. I'm getting about 8mpg in the city, 11 on the highway. I have taken it to what is probably the best auto shop here in Costa Rica and they have supposedly taken care of the problem, but it persists. The first time, they found a loose seal that they thought was causing evaporation so they replaced it and also cleaned the injectors. The second time, after I didn't see any improvement, they found out that it didn't have a thermostat and an oxygen sensor was bad, so they replaced both. I'm still not seeing any improvement. It wouldn't be so bad if gas didn't cost more than $5/gallon here. Questions:

1. I changed to 17" tires, hoping to see some change (no)
2. I read that sometimes the computer needs to be reset. Is this possible in my case?
3. Related to question 1, how can I calculate actual mileage if I'm running with 17" tires and not stock 15"? Is there a big difference?
4. Anybody want a trip to Costa Rica to come fix this thing for good?

 

[Turdle]

I'm down for a trip!!

Seriously though, does the torque converter lock up at highway speed? you should be in the range of 2000-2200 pm's at 65mph.

 

[ergibbs]

Thanks for the response. 65mph is impossible on the highways here - the best I can ever do is 55 for short spurts due to traffic. The term "highway" is used loosely here. Basically if a road doesn't have stop signs or speed bumps it's a highway. On a trip of 168 miles (one way) I averaged about 45mph.

 

[Turdle]

Oh, well, then that is mainly "city" type driving. Highway mileage will climb once the vehicle can cruise a long time at speed. Slowing and accelerating --the transmission is always hunting for the correct gear. In this case, I believe a lower gear ratio, or, smaller tire would help. Less mass to move around.

How much stuff do you haul? 100lbs =1mpg in stop and go traffic.

 

[ergibbs]

I wouldn't say there was a lot of stopping and starting; just cars not moving very fast. I would calculate about 400 pounds total between me, the wife, 3 lil ones and the suitcases.

 

[ergibbs]

I forgot to mention that the beast also has a 4" lift on it.

 

[IAmTodd]

What is your current tire size and type? That has a huge different when it comes to mileage. What type of terrain are you driving on? Lots of hills or lots of flat land?

 

[Turdle]

http://www.explorerforum.com/forums/showthread.php?t=254086

^^^^ 15+ MPG , once it got cruising 60-65 mph.


8-10 MPG around my rural area.

 

[IAmTodd]

I guess mine stock evens out at a consistent 13-15 regardless of the type of driving.

 

[ergibbs]

The tires are Firestone 30x10.50R15. I thought they were 17s. I'd love to get 13-15mpg. I'm spending about $600 on fuel right now and it hurts every time I go to put gas in it.

 

[IAmTodd]

Have you cleaned your MAF? I had to remove the screen on mine and use a brush to get the build up off it. Any stored codes?

 

[R&T Babich]

... Seriously though, does the torque converter lock up at highway speed? you should be in the range of 2000-2200 pm's at 65mph.

Depends on his rear gear ratio. I think a "base" 4dr 2wd XLT Explorer comes with a 43 axle, 3.08 gears. Our '93 2wd is a "base" XLT with 3.08 gears and the rpms are in the range 1750-1900 at 65mph. Our '92 is also a "base" XLT and had the optional heavy duty axle with traction lock and 3.73 gears (D4). To get a traction lock the gear ratio is either 3.73 or 4.10 (haven't seen a D2 axle, yet). The rpms were in the 2000-2150 range at 65mph. After replacing it with a "stock" 3.08 axle rpms are now in the 1750-1900 range. We haven't seen much difference in acceleration from a stop or going up hills, but I do like the lower rpms. I think most (don't know the numbers) 4dr XLT/EB Explorers were 4wd with the 3.73 traction lock axles. I did see a 4wd Explorer in the junkyard with a 41 non-traction lock axle, which was kind of strange. I checked the wheels and it was definitely a non-traction lock axle. Our old parts '92 4dr 4wd has the 3.73 axle and the best mileage we ever got with it was 15 mpg at 70mph. Usually it got 12-14.

 

[ergibbs]

I don't know if they checked the MAF; I'll have to ask.

Is there any way to run this engine without the computer? Take it out of the equation completely?

 

[IAmTodd]

No, the computer is what pulses the injectors, determines the amount of fuel, ignites the spark plugs and when to do that, when to lock the torque converter and engage overdrive. A full host of things but yes, it is absolutely necessary to run the truck. You can get away with out a few sensors but only for testing.

When I first got my truck I had to run it with the MAF disconnected until I troubleshooted its running issue. It wasn't optimal but did run.

 

[ergibbs]

OK, thanks. Is it true that, if the fuel regulator were faulty, the plugs would be black? They were just replaced in October. Maybe not enough time has elapsed for them to show indications of a faulty regulator?

 

[IAmTodd]

Have you tested the fuel pressure? There's a guide on here somewhere. I just can't locate it right now.

If you pull the vac line of the regulator is it dry or does it have fuel in it?

 

[ergibbs]

I don't know if they tested the fuel pressure or not. I'll check the vac line and report back. Thanks

 

[jd4242]

What axle code do you have?

 

[ergibbs]

I'm really not sure what the axel code is. How can I find out? One thing I can tell everyone for sure, is that after having the injectors cleaned, installing a thermostat and replacing an oxygen sensor, there is absolutely zero change in the consumption. I'm still getting about 8mpg.

 

[IAmTodd]

The axle code will be listed on the white tag located on the drivers door. Has a lot of the configuration information for the truck. There's a section that says Axle. It will have a two digit code. That cross references to the gearing that is in the axles. The code is Explorer specific so if you google it, make sure you're looking at the Explorer codes as different models have the same codes but map to different ratios.

Have you checked out your MAF sensor and looked into cleaning the idle air controller?