[muddman]

my 86 is only getting 12 mpg it's a 22r motor, I don't have time to rebuild yet but I will soon, in the mean time other than the plugs and wires, something has to be seriusly wrong what could that be? any info would be great and thank you.

22r, 5 speed, 4x4 and 255.555 miles.

 

[myyota]

What about the timing, did you check that ?, also check for vacuum leaks, either one of those can screw up your gas mileage.

 

[jlangdon]

does the truck still run really well? Is it noticably different from when it was getting normal gas mileage. It sounds like a carb issue to me. It could be a choke not opening properly or the float sticking (both would cause the carb to put out a lot more fuel than needed but usually the thing wouldn't run very well if that was the case too. Vacuum leaks will normally make an engine run lean unless the leak is effecting something like a choke or vacuum advance. I'd consider a carb rebuild if it's never been touched. Also check compression if think the truck is down on power.

 

[phburks]

my 86 is only getting 12 mpg it's a 22r motor, I don't have time to rebuild yet but I will soon, in the mean time other than the plugs and wires, something has to be seriusly wrong what could that be? any info would be great and thank you.

22r, 5 speed, 4x4 and 255.555 miles.

as mentioned, you can check the timing. also check your air filter and fuel filter.

was this a sudden change or has this been consistent for a while? are you noticing any black/dark smoke from the tailpipe? what size tires are you running?

also remember that the 4x4 trucks are known to get lower gas mileage because they are quite a bit heavier than 2wd trucks. depending on your truck's setup and driving conditions, your mileage might be about all you can get.

 

[muddman]

thank you

thank you for the responses
I traded my old ford for this truck, and so I don't know alot about it.
I think the timing is off alittle and I tried to ajust it but I couldn't get the distributor to turn I think it is a little to far retarded becouse it is back firing out the tail pipe, It does run ok when i'm running it but it does feel alittle slugish. but it doesn't burn any oil. how would i go about checking the choke for proper oporation. thanks
the tires on it are 235 15
also is a carb rebuilt very tuff on the toyota this is my first one and so farr i love it.:thumbup:

 

[jlangdon]

Those carbs have a lot of parts but they are pretty straight forward. There is an 85 FSM in .pdf form floating around in this forum that would help you. The 85 settings might not be perfect for your truck but they basic carb design should be the same and it would be a good guide. It would also tell you how to properly check the choke and all of its operation.

The choke should be fully opened when the engine is warm (just to give you a starting point). If it's staying partially closed then that is the first thing i would adjust/fix.

 

[muddman]

hey thank you very much if I recall the choke was not open all the way last i messed with it.

 

[jlangdon]

i'm not sure if a choke partially closed will knock mileage all the way down to 12mpg but it sure as hell wont help anything. Only as a trouble shooting measure you could tie it open with some safety wire or something to see if it helps. It probably won't run that great cold but once it's warm you should get a decent read on how it affects mileage.

Just as a barometer for where you should proabaly be i have a bone stock fuel injected 85 4runner (heavy with the tallest factory 5-speed gears) and my mileage is usually between 19-23 depending on the time of year and how hard i drive. I would say it's low to average mileage considering some of the numbers i've heard from people on this site.

keep us posted

 

[390FE]

I rebuilt or at least cleaned my carb out. I got a kit from the local parts store and used the dirrections it came with. I didn't mess with any setting or screw adjustments on it. Just the choke because it had to come off to disasemble it and put in some of the new parts. Before rebuilding this carb I did one ford 70's 2 barrel. The Ford was easier but I had no problems with the Toyota one. I looked around to have it rebuilt and not many people are rebuilding carbs anymore.

And I am getting 18-19mpg ('87 22r 4x4 5speed) mixed driving but mostly back(country) roads. And my foot is probably into it to much all the time.

I also have the timing a bit advanced. If I remember correctly its at 9deg advance (at idle) with all vaccum hooked up.

 

[muddman]

great news

I have no idea what i did but there is a little cylider shaped thing (almost looks like a fuel pump) just under the carb and i pulled off the vacum line that run into the top of it and pluged it, also there was a vacum line that came of the airfilter cover that was sucking so i pluged that one off aswell. it took care of two problems one the back firing out the tail pipe and two it doubled my fuel mileage. does anyone know what the problem is. thanks.