I've been having a problem with my 4runner. I have an 85 with a 10 inch lift and 37 inch tires with a 3.0L v6 engine.. i know the gas mileage shouldnt be "great".. but i've been getting about 75-80 miles on a full tank of gas, I don't think it should be that bad. Are there any suggestions of what might be causing this? any help would be greatly appreciated. thanks

 

i take it this has not been the normal for your rig? what gearing are you running? also an obvious question is if there is a check engine light on? mileage that bad i would check the simple things like leaks and maybe look into testing your O2 sensors. also, and i hate to say it but check head gasket..? just throwing out some ideas.

 

How many gallons of gas are you using for that "full tank"? And as mentioned before, what gears in the axle? You likely need 5.71s for that size tire. And are you correcting the miles traveled for the gearing and tire size?

 

well the thing is i just bought the rig about a week ago.. so i hardly know anything about it such as the gears and all that. the check engine light is not on, but for some reason since ive bought the truck the "rear anti lock" light has been on..idk if that has anything to do with it. also a "full tank" of gas is 14.5 gallons.

 

Gearing information below:
- http://www.4crawler.com/4x4/4R_TechI...oDetermination
- http://www.4crawler.com/4x4/4LoCalc.shtml

If the gears are not proper for the tire size you have a number of factors working against gas mileage.

1. The engine is working harder than it normally would and is turning slower and not running in it's optimal RPM range.

2. Your speedometer will read too slow and if you are driving at an indicated 65MPH, you'll actually be driving much faster than that, more speed = more air drag on the vehicle = more load on the engine = less MPG.

3. Your odometer will be reading low as well, meaning you drive an indicated 80 miles but you may have actually traveled much farther.

 

Thanks for that..I appreciate it!

Another thing i've been trying to figure out is the speedometer and the odometer.. it doesn't work.. the RPM's gas, oil, battery, all that works.. just not the speedometer and odometer..any ideas?

 

Follow your speedo cable all the way down and make sure it is connected into the trans case. and that it is not broken. Or when it was lifted the cable may have been to short.

 

Check the speedo cable. Is it even hooked up?

So you must be more or less guessing as to the mileage between fill ups, since the odometer isn't working. But, if what you are saying is accurate, you are only getting about 5 mpg.

Check the gearing as has been mentioned, and then go from there.

 

the speedo cable is connected and in perfect shape.. i did take off the dash and disconnected the cable from the back there was a bunch of grease in there.. could this be causing the problem? im trying to clean it all out. also when i took an allen wrench about the same size as the cable,put it into the back of the speedometer and turned it to see the gauge would move.. it did.. so im guessing its the grease build up.. hopefully it works after i get all of the grease out of there

also.. about the mileage between fill ups. 75-80 miles is what I get.. yesterday i filled up went a total of 80 miles (mapped out my exact route on mapquest) and then had to fill up again because i was completely out of gas

 

is there a way i can tell if the speedo cable is spinning or not?

 

 

One option would be to unplug both ends and have someone turn the transfer case and end watch for the speedo end to turn. Or put the rear axle on jack stands and let the engine run in gear and see if the speedo end of the cable spins.

 

IIRC, I checked mine by inserting the trans case end into a cordless drill chuck and then taped the trigger to make it run. Then I checked the other end. I was able to do it by myself this way. It has been several years ago, but I am pretty sure that is how I did it.

 

Also check the speedo drive gear at the transfer case. They are just plastic teeth and WILL shear easily. This is the most common reason for inop speedo/odo.
Remove the 10mm bolt and just slide the whole piece out. You'll probably find the teeth missing. I bet your dealer has them in stock. Common stuff.

As far as the mileage goes, that is way excessive. Does the exhaust smell like it's running rich? Does it start and idle normally? Rough idle? Have you pulled one of the plugs too check for over rich/excessive fuel?

 

thanks guys ill give em a try.

as for the starting and idling... thats fine. i think i might just do a full tune up.. flush all fluids..plugs..wires.. and see how that goes.

 

what kind of fuel pump does it have a mechanical or electric. what sort of fuel modifications were done for the 3.0L. i would assume swapping everything from the donor truck but who knows what was done.

 

im not even sure man, im trying to get a hold of the guy that I got the rig from.. ill take a look at it all today..

 

im gonna to do a full tune up on my rig.. but i have 3.0L v6 instead of the 2.4L 4 cylinder..to get everything that i need can i just buy parts such as plugs ,wires, filters, etc. for an 88 4runner which has the 3.0L v6.. or how would i go about doing that? its kind of confusing going into an auto parts store and me having the v6 in an '85..

 

assuming that everything has been swapped out then that would be fine, but make sure that you tell them the exact year of the engine has some things may change from year to year

 

is there a way that i can find the year of the engine?... i just bought the rig about a week n a half ago.. so i dont know much about it