MPG down after tune-up

[SLEEPR]

Hello!

I recently purchased a '94 Hilux Surf SSR-X. Of course it was poorly maintained before I got it at 89,000km. First few tanks of fuel gave me about 20MPG. I did some work, and now the MPG are much lower, about 16. Here is what I did to the truck, any ideas what happened?

new tires (from stock size 265/70r15 to 31x10.5r15)
new fuel filter (ran 50/50 ATF/diesel in filter when changed to clean injectors)
changed oil and gear oils
changed air filter
added 1/3 can of Seafoam (http://www.seafoamsales.com/motor-treatment/index.html) to the fuel tank
new batteries
greased drivetrain

I know the tires would change the MPG, but only slightly as they are only 4.8% larger. I've lost nearly 25% of my mileage efficiency! Did I damage my injectors with the ATF and the Seafoam? How can petroleum based prodcuts wreck injectors?

Thanks in advance for your ideas!

[BUSHWHACKER]

What are the tyre pressures?

[biosurf]

How were you measuring the MPG?

[SLEEPR]

I'll check tire pressure and get back to you. I think it was 35 PSI. What should it be?

When I fill up, I record the distance travelled on my trip meter (km), and divide by the number of liters of fuel I just put in. I always follow the same fill procedure; fill until the hose automatically turns off, then fill again until it turns off again. I typically get in an extra 1.5L this way. Then I convert L to gallons and km to miles to get my mileage. Been doing the calculation for years with all my cars.

[stormforce]

what was the last amount of km's you got and from how many gallons

[SLEEPR]

I have the info at work, will post it up on Monday

Will also check cold tire pressure tomorrow morning when I fix my antenna.

[SLEEPR]

First tank of fuel when I got the truck (SEP01):
303km on 38.000L = 12.54L/100KM or 19.0MPG

Most recent fill up (OCT16):
297km on 42.733L of fuel used = 14.39L/100km, or 16.6MPG

Tires are 35PSI when cold.

[Paul1566]

Think you got your maths wrong.

303km = 188 miles 38 litres = 8.35 gallons 188/8.35= 22.51mpg

297km = 184.5 miles 42.73 litres = 9.39 gallons 184.5/9.39= 19.64mpg

Don't know why it should be down after the work you done.
Maybe worth a shot of redex and drive it with ect on for a tank
give the injectors a good clean through.
Think i got me last redex from wilko's, half the price of halfrauds.
Mine only does 22mpg but it does it uphill down hill fat footed and driving like a fairy.........did get 25 once doing a long stint on the motorway....
then back to 22 as usual.
Could be that the seafoam has loosened the bits that build up and fill the tiny voids that aid compression.

Doh! read before leaping....not sure you have Wilko's in canada or the good old Halfrauds....

[SLEEPR]

I was using the US gallon since I am in Canada

Regardless of raw numbers, the downward trend is present. I don't even know if we have redex in Canada. Is Redex the product name? I will look around. Assuming the ATF and the Seafoam loosened buildup which is causing problems, should I run some more injector cleaner in the fuel, run with the ECT and drive it hard for a tank?

[MattF]

Have you checked to make sure that you have no fuel leaks from the injector pump or fuel lines? The problem appearing when you did the service could be entirely coincidental.

[Paul1566]

Once again i type without reading...sorry....Sounds worse in us gallons than uk gallons....
When i first got my truck she was doing about 19mpg and I found that after a dose of redex (diesel injector cleaner)
with a tank of fuel my mpg went to 22 and has been that ever since.
I should really get them cleaned and reset properly but funds are tight and she's running so i am leaving alone.
Some boys on here get upto 28mpg, i only dream of that.
As Mattf says could have opened up another problem when doing the service.
I managed to wash my truck and take out the ecu, total coincidence but makes you look at the problem in a more direct way, wash = water = short circuit = dead ecu,
rather than its 15 years old, tired and used, and decides to give up the day i wash her. Nothing to do with water just damned expensive to fix.

By the way how much is diesel a gallon over there ?
Over here its roughly £4.95/gallon thats about $8.64/gallon ($canadian) i'm learning....

[SLEEPR]

I considered that I might have a leak. I parked on dry pavement for a few days and looked for signs of leaking, also crawled around under the rig and didnt smell any diesel. Are there another other things I can do to check for leaks?

By the way, my truck has no smoke, even on start up. It used to smoke when I started it, but since changing the batteries and running the ATF through the fuel filter, the smoke has gone away. Is this an indicator of lack of build up?

You guys are going to hate me for this. Diesel is about $0.83/L here.

I fill up again tomorrow, I am going to toss in some injector cleaner and run her hard with ECT on.

[biosurf]

[QUOTE=SLEEPR;592218]

You guys are going to hate me for this. Diesel is about $0.83/L here.

QUOTE]

Out of interest how much is vegetable oil? If its cheap then use a blend of that and stop worrying about MPG.

[Paul1566]

48pence per litre.... i remember those days.....just.

[MattF]

Some boys on here get upto 28mpg, i only dream of that.

I just have nightmares where the Surf's fuel consumption is concerned. At least she's consistently bad though.