ok so I need some advice. I have a 1987 vl calais. The first 6 months I had her she would average 10 litres/100 kms. Thats a mix between around town and freeway everyday. Then I drove her to NSW...bad idea. She now averages 12-13 and I cant figure out why. I know this is still good but I want it back to how it used to be. I have a full exhaust system: 2.5" high flow cat, sports muffler and genie extractors, replaced the o2 sensor, replaced the airflow meter, replaced the coolant temp sensor, has a pod filter, fixed the slow leak in my tire and even had it tuned at all sparks. the dyno print out shows that its using less fuel but its not. And I baby her when I drive her. My injectors were leaking a bit externally so I changed them yesterday.. admittedly they're not brand new but they looked decent. Any suggestions? Should I pay the big bucks and get her chipped?

Could be fuel filter or something like that? Slap some 98 octane in her for a while and see how she goes.

thank you Some original photos have not been recovered yet.

dyno reads air fule ratios. can it do this on a standard ecu? seems your getting two diff result\s My point is a) dyno is telling you its using LESS fuel than- b) The 25 Y.O. dash. long trip id change the fuel filter $15. P.S on long trips u get intimate with the fuel guage. This may play with you perception of fuel usage vs driving conditions.

lol 12/13 is much better than mine i get arround 150kms to a tank!!! i think im running abit rich lol

Easy fix SHAKEN, just bolt a turbo on and run 24 PSI then u will get good economy

Lol I'm running 10 psi ATM I haven't been game to try 24 lol

Just out of curiosity, how did you figure out your km/L. Did you keep track of the odometer, and then take note of how many L of fuel it took to be full, or did you just fill up when the tank was around Empty? If you didn't do the math and say, 40L of fuel to fill up and I did 500km on that run etc etc, it'll be completely wrong. Sounds like you're still getting good economy. Just make sure everythings in good condition, clean strong spark, decent fuel, don't drive like an idiot, tyre pressure up and all that and you should be fine. Spending a tonne of money for dyno runs and replacing sensors will end up costing you more than than the extra 5 dollars a week on fuel.

Make sure your engine oil is topped up and not sludge; causes unnecessary friction.

This is the most accurate way you can work out how much fuel your car has used. I do this from time to time in my VL n/a 5 speed. 1. Fill your tank up till the pump clicks. 2. Reset your trip meter to 0 or if it dose not work write down your odometer (167157) 3. drive until your near empty. 4. fill up the car until the pump clicks, the number of liters displayed on the pump is how much you have burned (53.27L) 5. work out how many km you have driven, my odometer now reads 167525. So i have traveled 368km 6. Now the maths: 53.27L divided by 368km 53.27L / 368km = 0.14475 (which is your L used per km) then multiply 0.14475 by 100 0.14475 X 100 = 14.4755 L/100km Round it off to four significant figures (14.48 L/100km) and you have it.

Quote: She now averages 12-13 and I cant figure out why. I know this is still good but I want it back to how it used to be. I have a full exhaust system: 2.5" high flow cat, sports muffler and genie extractors, replaced the o2 sensor, replaced the airflow meter, replaced the coolant temp sensor, has a pod filter, fixed the slow leak in my tire and even had it tuned at all sparks. the dyno print out shows that its using less fuel but its not. And I baby her when I drive her. My injectors were leaking a bit externally so I changed them yesterday.. admittedly they're not brand new but they looked decent. You can make any bet that you have leaky fuel injectors, is the car an auto or manual, when the o/d was slipping in my first VL a change to a 5 speed manual transmission made a lot of difference. When I was driving that car 80 kms per day, city/highway cycle I was getting 33 MPG out of it, a far cry from the 22 MPG it was getting when I had the automatic in it, yeah, that's about 12.5L/100 kms which was shocking, 33 MPG is 8.4L/100 kms, that was out of an N/A single cam RB30 which is a lot better I was using Shell Optimax at the time so I was getting more kays out of a tank of fuel, it turns out I was paying the same for that as standard unleaded. I get better fuel economy out of the LS1 than what you're getting out of your RB30 powered VL , I fill my car up once a fortnight and got 11.1L/100 kms (about 24- 25 mpg), that was 1 trip into Newcastle & back home (80 kms of city/highway driving), the other was a trip down to Lake Macquarie way (Argenton, 100 kms there & back) and the rest was just random trips into town (22 kms in & back), so I tallied up about 465 kms and the display showed I had 110 kms worth of petrol left in the tank. That's pretty good because I didn't really go anywhere the fortnight before and I got down to about 55 kms worth of fuel left in the tank.

Also check your timing & fouled plugs.

How are you guys calculating your fuel usage? I cant see how any one could get 12 and lower out of an RB30. My VL is immaculate mechanically and maintained like an aircraft and the best i get is is around 14.3L/100km using the calculation method stated above. ---------- Post added 21-07-12 at 23:45 ---------- Quote: Originally Posted by RB30DEVL [View Post] You can make any bet that you have leaky fuel injectors, is the car an auto or manual, when the o/d was slipping in my first VL a change to a 5 speed manual transmission made a lot of difference. When I was driving that car 80 kms per day, city/highway cycle I was getting 33 MPG out of it, a far cry from the 22 MPG it was getting when I had the automatic in it, yeah, that's about 12.5L/100 kms which was shocking, 33 MPG is 8.4L/100 kms, that was out of an N/A single cam RB30 which is a lot better I was using Shell Optimax at the time so I was getting more kays out of a tank of fuel, it turns out I was paying the same for that as standard unleaded. I get better fuel economy out of the LS1 than what you're getting out of your RB30 powered VL , I fill my car up once a fortnight and got 11.1L/100 kms (about 24- 25 mpg), that was 1 trip into Newcastle & back home (80 kms of city/highway driving), the other was a trip down to Lake Macquarie way (Argenton, 100 kms there & back) and the rest was just random trips into town (22 kms in & back), so I tallied up about 465 kms and the display showed I had 110 kms worth of petrol left in the tank. That's pretty good because I didn't really go anywhere the fortnight before and I got down to about 55 kms worth of fuel left in the tank. Sorry bro I have to say it. That is a crock of ****. 12.5L/100km to 8.4L/100km out of an RB30E. A hybrid Camry 2012 model uses about 7L/100km from Nth Ryde in Sydney to Wollongong which is a very fair mix freeway and city driving. How did you calculate 12.5L/100km and 8.4L/100?

Haha I get around 250 to a tank on my vlt....

I just cruised up to Brissy and got 450+klms out of my stock tank, 98 octane.

Thanks guys I calculate it the way you suggested. My fuel gauge doesnt work anymore so I do 200-300 a kms and fill up. Its really temperamental. Sometimes after Ive done 300 kms it will fill up with 30 litres and other days it will fill up with 40 litres. I drive like a granny. All my oil is topped up, everything is tuned right. The injectors arent leaking externally (Ive been told if they were leaking internally the car would run like **** which it doesnt). It runs and idles perfectly and my tire pressure is set to 32 psi. I just dont get why it changes so much from week to week when I do exactly the same trip. Some original photos have not been recovered yet.

Have you been using the E10 fuel?? Also you might have picked up some sh!tty fuel.

I just use standard 91? I was thinking that. one week its good. one week its bad etc etc.

As a side note. Have you tried the fuel gauge fix in the tech articles? Driving without a fuel gauge is annoying as hell.

Yeah ive had a fiddle. ive taken the dash off and everything seems fine the car only has two problems and no one can seem to figure it out. the gauge (think i have a broken wire somewhere) and the fuel economy going from good to bad weekly Some original photos have not been recovered yet.