EPICjurneez

my '94 4x4 pickup with it's 5spd 22re motor gets inconsistent fuel economy and power. Can anyone help figure out this riddle?

Symptoms:
1. I've acheived 26 mpg putting though the high/steep mountains of colorado on one tank. Other tanks of fuel in the same high elevation region yielded 24 mpg! that's carrying my wife and me with my xtracab and campershell'd bed filled with camping gear and a tandem kayak and two mt. bikes secured to the 200lbs lumber rack!

2. Back down here in the reality I know as southern california, I usually suffer 18~19 mpg per tank of fuel. This is mostly hwy driving, alone, for commute.

So, that's a big difference... I know toyotas and their 22re's are known to be more consistent than that. So, what gives?

I've told this to Dealership Mechanics and private garage 'guru's and nobody can do anything to my truck engine to bring consistency. So here I am, back here at yotatech.

First I thought it was my fuel choice... The theory didn't hold.

Now I'm pretty sure that it is air humidity and or oxygen density... Think about the high mountains and the thin arid air in those regions... my lips are chapping as i think of it. Then consider my relatively humid, coastal region I live in, rich in all its sea-level oxygen density.

So, to you gurus of yota tech! What's my pickup suffering from?

my truck's probably had this issue before i bought it at 118k miles... The mass air flow sensor (the assembly that caps the air filter element) had been tampered with. A friend recently thought it was that and i told him that i replaced it with a non-tampered mass air flow sensor. So i don't think it's that (now i'm at 212k miles). could it be the oxygen sensor? Please Help!

William

iamsuperbleeder

Ha, Id be happy with either one of those #s; my 91 averages 16-17mph no matter how hard or soft I step on the skinny pedle, and highway and city driving make no difference either for me

The O2 sencor could be a factor, definately if it's the original, considering they normally only last 100k (the original on my 91 lasted 278k though )

I'm assuming you've tried the simple tast of running a fuel cleaner through? Sometimes those little bottles can actually work as advertised, but with the 22re, the problem often lies pre-injectors, or up in the upper intake plentum and the throttle body.

Have you taken a look inside your throttle body lately to check for buildup? These motors are quite common of that, and it's been tagged the "black goo" syndrom around these part; I had a run-in with it myself...

Pull the rubber intake hose off your throttle body, grab a flash light, flip the throttle butterfly valve open, and take a look down into the plentum. I don't have to tell you want to look for; if your motor's cought it, it'll be noticable...

Good luck!

Flash319

Those are very good numbers. The inconsistency may be your calculations. 2MPG is not a lot. How full are you filling the tank when you fill it? I know that if I keep squeezing fuel in I can get an extra 50km out of a tank on that alone.

Because it is a 5 speed the speed you travel will have a very big impact because the truck is over 3K rpm when going 65+ (depending on tires) If you go 90km/h (55miles per hour) You can save about 15% or more. I have done this because I commute a log ways and have tried different things.

Your numbers are to good and to close together to point to any problem. 22RE's are not good on gas, but the milage out-ways the longevity of them.

abecedarian

On the other hand, California has some specific requirements for fuel formulations....
maybe your mileage variances are related to that?
This is Democratic controlled (eff schwatzabugger) nearly communist state...

Bako88

Thanks for the link Abe. I just skimmed through it.

Also- sounds like you appreciate the governing body of CA about as much as I do. Just like Oregon, CA is beautiful landscape with a crappy government.

abecedarian

the link? oh... you mean the 35 Inconvenient Truths about Al Gore's Inconvenient Truth (casually known by the name "where Al Gore and others LIED")

edit- it's been bantered about over the last decade... maybe more... that if California would've bought brand new Cadillacs to replace gross polluters, it would've met the goals for emissions and saved over a billion dollars more than it did promoting electric vehicles.... but that was the 90's.

EPICjurneez

Ok. I forgot to rule out the possibilities of tank fill. I wonder even about the different fuels of the different states. But even out in the high desert where the air is thinner and drier, the engine still eeks out 20+ miles per gallon. near the humid/Low elevation coast area where I live, my truck gets the 18~19 mpg ( these figures are recalculated from what my odometer reads which is 16~17 -- I then add 1.11% to account for the diameter change from stock 215 tires to 31")

With that said, I'm thinking it must be the oxygen sensor or the black goo syndrome that Superbleeder mentioned. I don't remember my o2 sensor ever being changed. what are other symptoms that could lead to? can you tell me where its at so i can change it? reccomendations for any specific brands to replace it with/ where to get it?

I'll check on the throttle body too! Thanks for all your input!
William

Flash319

Just remember those are not that bad of numbers. Your engine has higher milage and will not be as good as new. Most guys that report problems are going from 18-20 mpg to 10-12 mpg. This is the kind of drop that will point to bad O2, TPS, Vacuum leak, leaking cold start injector, bad timing.........ect

Because it is fuel injected, if it is running good, with no service light you probably have no problem. You can try changing O2, spark plugs and a general tune up but I think you are looking for something that you will never find......

abecedarian

18-20 isn't really all that bad. My 88 5sp on 31's, stock gears, get's around 20-24 or so around town and my 91 auto does about the same.
I am gonna pop up that cali-gas thing. Cali requires oxygenated fuel year-round, and it's even worse in the winter. It doesn't produce as much power when burned as the normal gas elsewhere. Even my vehicles average about a 3-5 mpg drop going from the summer blend to winter blend.

Bako88

What symptoms do you get from a leaking cold start injector? Do they typically leak all the time or intermittently? How do you test for this?

abecedarian

They can leak.
Pull the injector out of the intake and jumper the fuel pump on... look for leaks.

EPICjurneez

thanks Flash319. i'll keep that in mind. i'd love to get the 20-24mpg that abecedarian gets in temecula!

what's with all the 22re owners being familiar with tdi's. I've owned one since i purchased it new in '98! it's been getting me 50~60mpg with a record of 65mpg on an 'experiment' drive from oregon to home. i almost purchased a new cleandiesel tdi but decided to try to get another 100k miles out of my '98.

Thanks for all your help on my truck...i'll assume it's just age that it runs the way it does. sure is mysterious that it gets up to 26mpg in colorado though.