Terrible Gas Mileage

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Blueaussie

New member
Hello can anyone give me advise on the terrible gas mileage I am now experiencing on my 1995 Toyota 4runner. I had a re-manufactured engine 3VZE 3.0 6 cyl from ATK North America a year ago.

I normally would see at least get 100 miles on a half a tank of gas driving in the city. At this time I use 3/4 of a tank to get the same 100 miles of same driving.

I had the fuel pump changed along with a new fuel filter. Also had reconditioned fuel injectors installed at the time of swapping engines.

I have always ran high octane gas along with BG gas treatment a few times.

The engine runs very smooth. No miss fire. It does idle a bit too high but not enough to see this much decline in fuel efficiency.

The vacuum is with in specified range. Brand new Yokohama original tires on the vehicle.

I am at a loss...any advice is appreciated.
Thank you!
 
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That does sound pretty bad. Are you carrying anthing heavy with you on the 100 Mile trip? What is your average speed on this trip?
 
You might check the fuel pressure (rest and running). I always change out the regulator when doing pump replacements. It is just a small rubber diaphragm. A new pump will blow an old regulator out quite easily, and the ethanol their putting in petrol these days does not help either.
On the MPG front, I would check the following:
1) tire pressures
2) fan clutch / t-stat (if sticking, it can keep the engine in enrichment mode)
3) O2 sensor (toyota's are sensitive to them)
4) vacuum leaks
Comment: Since you've done injectors, make sure it's not leaking around the housing. Many people don't replace these seals, because they don't know they exist beyond the ones for the injectors.
5) you might consider some new NGK coppers and an air filter while in there
6) check the front calipers are not binding up
7) check timing
Best of luck with it.
regards
 
Manual or Automatic trans? I'd check what 77'911 recomends. Also check your compression if you can.

FWIW, I used to run 89 octane in my T4R, but with gas prices I switch to 87, though I don't notice any difference in mileage. I get about 270 miles on a full tank around town, but I don't go on long trips as I use too. Though it's been a while since I filled up to a full tank, most of the time it's $20-$30 @ $3.50 a gal.
 
77'911 said:
You might check the fuel pressure (rest and running). I always change out the regulator when doing pump replacements. It is just a small rubber diaphragm. A new pump will blow an old regulator out quite easily, and the ethanol their putting in petrol these days does not help either.
On the MPG front, I would check the following:
1) tire pressures
2) fan clutch / t-stat (if sticking, it can keep the engine in enrichment mode)
3) O2 sensor (toyota's are sensitive to them)
4) vacuum leaks
Comment: Since you've done injectors, make sure it's not leaking around the housing. Many people don't replace these seals, because they don't know they exist beyond the ones for the injectors.
5) you might consider some new NGK coppers and an air filter while in there
6) check the front calipers are not binding up
7) check timing
Best of luck with it.
regards
Click to expand...


77'911 thanks for the info! will check these out. Again thanks.
 
Have you checked your valve clearances? Since the engine was re-manufactured a year ago, I doubt the valves are off. One of my valves was loose and it ran horribly and I was getting 9 MPG... I adjusted them now I'm up to 21 MPG.
 
Blueaussie said:
77'911 thanks for the info! will check these out. Again thanks.
Click to expand...

77-911, On the NGK Coppers you mentioned....are you referring to new spark plugs. It has new NGK Spark Plugs in there when the remanufactured engine was installed. I don't think their copper though. I did change the air filter. As for the Fuel regulator I really should not have messed with it. I FU really bad by replacing it. They made the 1995 3.0 6 cylinder in such away that you have to rip our the whole top intake manifold/throttle body tons of vacuum lines, coolant lines ect, ect.

Well I could not afford to pay a shop to do this nor can I do it my self I have to have a 4th back surgery with in 8 years and just can't physically do that. It is even getting hard to find repair shops work on vehicles that are not compliant with the use of a scanner for troubleshooting.

Now that I tore out the old fuel regulator I had to do some uneducated engineering to make a raiser out of metric nut and cut the old stem with the threads off the old regulator to make a raiser. It will start but you have to let the fuel pump run a little while to build up pressure before it will start. Apparently my engineering job is not working very well because the pressure in the system does not hold.

I need to find a specialty shop that stocks metric nipples/standoffs in an effort to tightening the threads sufficiently so it will hold the static fuel pressure it normally had before I made that stupid move in replacing it. If any one know of a place that I can get the correct stand off/nipple I would appreciate anyone's help immensely.

I love this 4runner for a vehicle that is almost 20 years old it is in great shape. The interior looks brand new which I was in disbelief when I picked it up for 500 bucks. The paint is some what faded but it's never been wrecked and everything works, power windows, locks ect.

Thanks 72-711 and to anyone that has some ideas.:crazy:
 
:yo:
Cartzo said:
Have you checked your valve clearances? Since the engine was re-manufactured a year ago, I doubt the valves are off. One of my valves was loose and it ran horribly and I was getting 9 MPG... I adjusted them now I'm up to 21 MPG.
Click to expand...

Cratzo, I have not checked the valves, I thought these did not require clearance checking...lol. I need to invest in a true reapair manual for this model. These Chiltons they sell at automotive car parts store just don't go into enough detail... How I wished that had the scanner hook ups for this year model for trouble shooting.

Thanks for your input!
 
Blueaussie said:
77-911, On the NGK Coppers you mentioned....are you referring to new spark plugs. It has new NGK Spark Plugs in there when the remanufactured engine was installed. I don't think their copper though. I did change the air filter. As for the Fuel regulator I really should not have messed with it. I FU really bad by replacing it. They made the 1995 3.0 6 cylinder in such away that you have to rip our the whole top intake manifold/throttle body tons of vacuum lines, coolant lines ect, ect.

Well I could not afford to pay a shop to do this nor can I do it my self I have to have a 4th back surgery with in 8 years and just can't physically do that. It is even getting hard to find repair shops work on vehicles that are not compliant with the use of a scanner for troubleshooting.

Now that I tore out the old fuel regulator I had to do some uneducated engineering to make a raiser out of metric nut and cut the old stem with the threads off the old regulator to make a raiser. It will start but you have to let the fuel pump run a little while to build up pressure before it will start. Apparently my engineering job is not working very well because the pressure in the system does not hold.

I need to find a specialty shop that stocks metric nipples/standoffs in an effort to tightening the threads sufficiently so it will hold the static fuel pressure it normally had before I made that stupid move in replacing it. If any one know of a place that I can get the correct stand off/nipple I would appreciate anyone's help immensely.

I love this 4runner for a vehicle that is almost 20 years old it is in great shape. The interior looks brand new which I was in disbelief when I picked it up for 500 bucks. The paint is some what faded but it's never been wrecked and everything works, power windows, locks ect.

Thanks 72-711 and to anyone that has some ideas.:crazy:
Click to expand...

At this point, a set of basic copper NGK's (usually $2 a piece at the local auto parts store) , might not be a bad investment. It sounds like your regulator is not doing it's job. They are usually about $90 for a Denso unit. You can usually leave the vac hoses alone, unbolt the intake(so it's loose), and it can tilt enough to R&R the regulator in minutes.
As a 20 year old vehicle, it probably needs a bit of TLC the previous owner has neglected. Best of luck with it, hang in there.
regards
 
Even if the plugs are brand new, if you're injecting too much fuel, and fouling the plugs up, new plugs will be old plugs in no time. Sound like the afro-engineered fuel regulator could be a viable culprit
 
Howitzer, I checked the plugs, they are ok. The problem started before I engineered the fuel regulator. Think I will fix it correctly before I look like your profile pic...lol
Thanks
 
Are your CVs and driveline in decent shape ??? Any drag cause by stuffed driveline components can contribute to fuel economy. Also, as trivial as it may seem, do you carry much in you 4runner when you are driving it day to day ???

On there own each of them probably don't amount to much, but a few them together would effect your consumption.
 
Pull the modulator cap off and clean the internal filter. Its function is to clean the vacuum
to the EGR. If you pull the top hose off the EGR and the engine smooths out, the VSV hoses are routed incorrectly.This is a mistake made by mechanics when the plenom gets pulled, replaceing the passenger side valve cover gasket or pcv valve. under center sticking out under pas plenom are three tubes.
code 71 and vacuum lines. - Page 2 - YotaTech Forums
 
DjB said:
Are your CVs and driveline in decent shape ??? Any drag cause by stuffed driveline components can contribute to fuel economy. Also, as trivial as it may seem, do you carry much in you 4runner when you are driving it day to day ???

On there own each of them probably don't amount to much, but a few them together would effect your consumption.
Click to expand...

DjB, I have not checked that out. I did have an alignment done about 6 months ago when I put the original Yokahoma tires on. No extra weight.

May just be the unusual cold weather we are experiencing down in the south IDK.

Thanks for your input!
 
bills86e said:
Pull the modulator cap off and clean the internal filter. Its function is to clean the vacuum
to the EGR. If you pull the top hose off the EGR and the engine smooths out, the VSV hoses are routed incorrectly.This is a mistake made by mechanics when the plenom gets pulled, replaceing the passenger side valve cover gasket or pcv valve. under center sticking out under pas plenom are three tubes.
code 71 and vacuum lines. - Page 2 - YotaTech Forums
Click to expand...

Bills86e, check your messages.
 
Blueaussie said:
Scaled, I did download that, Thanks, much better than the half ass Chilton's...lol
Click to expand...

Yeah I bought the junk Haynes manual when I first got my '95 4Runner… wasted cash. The FSM is SOOOO much better.

I'm interested in what you find with your MPG quest. I'm getting low 12's for mixed driving, not too happy with it but don't currently have a ton of time to tinker.

:pop2:
 
Ok got the Fuel pressure regulator installed correctly. Cleaned out EGR valve, it was filthy so was the flume/intake. When the Auto shop put the rebuilt engine in they never cleaned it up.

I replaced a lot of cracked and wrong size vacuum lines.
I sea Foamed the Vacuum system.
It does not idle anymore at 1000 RPM 1500 Cold.
Now it needs gas pedal action to start, idles at 500 warm 1000 cold.

Vacuum reading at 21 I searched the owner's manual I downloaded but have yet to find recommended vacuum. I am guessing it should be around 26 IDK

Will keep all updated

Work in progress.

:ybrick:
 
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