fuel /gas economy going up

[maddog Lurker Find all posts View Profile Close maddog]

hI, im tryin to find out why my fuel economy has droped. i have a 1997 vx 3.4 fuel/gas,
i use to get 400ks up to 435 out of a tank of gas from full to empty . at the moment when i fill up with about 73 lts of gas im batterling to get 365 out of it.
is it somthing to do with worm / v cold weather . or as there maybe somthing not corect .... motors done 200000 and ive noticed this over the last 2 to 3 months. same driving conditions. just cant sqeeze as much out of it as i could.... idd like to get it back up to getting 400 out of a tank agan. i once read somwhere about some sencer that can muck up economy ..... plug were done and oil change about 1 month ago.
any help would be great.

[xlr8_87 Advanced Member Find all posts View Profile Close xlr8_87]

Re: fuel /gas economy going up

Yeh I think the oxygen sensor is the one that can cause it to chew through a bit more fuel. Could just be the motor getting older though, especially if it's been on LPG. Do you run a lubricating fluid through the engine?

Also might just need a bit of a tune.

[maddog Lurker Find all posts View Profile Close maddog]

Re: fuel /gas economy going up

hi mate ,
i was going to look into the lube drip for it , but the gas was only fitted end of 2008 , so its only reay just been on it one year , cars very clean never used for full ofraoding , full log book historty etc.
cars starts every time on fuel then has the change over to gas once you drive of or tap the pedal switches over at about 1800 rpm. so realy every time its started its ran on fuel. i also swich to feal end of every tank or one a week for a short drive....
im gessing it the senser. i just picked up a can of CRC mass air flow senser cleaner. ($22.) from repco.... ill give it a go. im gessing its in the air intake right after the air box. ill pull it out and see want happens.....

[maddog Lurker Find all posts View Profile Close maddog]

Re: fuel /gas economy going up

well i used that spray , car seems to have way more power agan , ill see what k`s i get out of a tank now. but i do notice lot better throtal responce and no funny kick back, and a HELL of a lot more power ...all i can say is WOW,,, glade i nkow about this little sencer , just to think such a small iten can cause such a problem...
i gess every toyota macanic must carry a can of spray like that when the sevice the cars... haha.....

[xlr8_87 Advanced Member Find all posts View Profile Close xlr8_87]

Re: fuel /gas economy going up

Sounds like it could be something worthwhile spraying in there every so often. Where do you spray it in?
Might get a can for myself, $22 and it can't do any harm!

[maddog Lurker Find all posts View Profile Close maddog]

Re: fuel /gas economy going up

mate ill let you know after ive ran a cupple tanks and seee what k`s i end up see if i can get it back to befor. it sertantly has got loads more power back . seems a lot smother and better acceleration and gear change to ...
yep its the crc maf senseor spray $22 at repco, it probly can be cheeper. but it will last for a long time. big can . i got told NOT to use injector clear or carbi sprays as these are ment to damage the sensor prob`s ,small wires 4 of them . there in the air intack ducked past the air cleaner you will see it with wires pluged into it..
, like thay say tune up in a can . well thats what my mate that worked for holden use to say.... one can for intake one can for fuel.....make you realy wonder what thay do do when we spend all that money on a so called tune up....

[drocelot Lurker Find all posts View Profile Close drocelot]

Re: fuel /gas economy going up

hey how did you go with the economy ? I think I might go about cleaning my sensor as well.

[maddog Lurker Find all posts View Profile Close maddog]

Re: fuel /gas economy going up


well i drove the car for the last fortnight , doning normal around town driving , and gess what im back to
getting 426 k`s out of one takn, i filled up from empty with 73lt`s gas, and got bactk to doing 420+ k`s, thats great considering the last 5 tanks befor trying the spray i was only getting 360 k`s for 73 lt full tank. and doing nearly the exact driveing around town...
so from what i can see this realy dose work. and ill be checking more often now knowing this . also the car seems to run smother and has a little incressed power.

:wink: :wink: :wink: :wink:

[drocelot Lurker Find all posts View Profile Close drocelot]

Re: fuel /gas economy going up

thats great maddog i just pulled mine out and the wires are covered in a dark grey type of stuff..... I am only getting 350km out of my gas. I am 150kms from Rockhampton I have RP7 do you reckon I should try RP7 on it or wait to get some contact cleaner?

[maddog Lurker Find all posts View Profile Close maddog]

Re: fuel /gas economy going up

mate idd wait and get the proper map senser cleaner. reading somewhere you can damage the sensers.... if using the rong spray ... idd not like to say use it if it stuffs it right up your out what 260 + ..$$... when a can of map senser spray is what 20 max....
good luck with it i was very suprised . with the outcome...

[drocelot Lurker Find all posts View Profile Close drocelot]

Re: fuel /gas economy going up

cool i will wait, what did ur sensor look like dirty?

[drocelot Lurker Find all posts View Profile Close drocelot]

Re: fuel /gas economy going up

did the clean was getting 330km per 75ltrs of LPG now get 400 !! and thats towing..

also getting heaps better milage off the sub tank