Avensis mk1 fuel consumption

[Alex-avensis]

Hi all,

         I thought that I would share my cars fuel consumption figures with you, there may be one or two that will find this interesting. The car is a 1.8, been very well maintained, it`s been in  the family since it was only a couple of years old. The plugs were changed recently for the specified Iridium ones, air filter is also new, oil has always been changed regularly .

I brimmed the tank and reset the odometer, I drive carefully, never accelerate harshly, most of the mileage I do is at 60 mph on the A52 between Derby and Nottingham. So I was expecting really good mpg however I must say that I am very disappointed to report that I have only achieved 32 mpg :(  I was expecting something like 37 to 40 mpg. Was I hoping for too much?

Anyone else achieve better than this in their mk 1 Avensis? I`d be very interested to know.

 

                                                                                     Alex

 

 

[thomjones83]

I have a 1.8 mk2 and on a run to Ripon and back (again taking it easy, about 130 miles on the a1) I got 48mpg.maybe try a fuel treatment like redex

 

Sent from my SM-G920F using Tapatalk

 

 

[Alex-avensis]

Hi Thom,

               yes I will try it, thanks :)

[talldave]

I have a 1998 1.8 auto - so not directly comparable as it's an auto. My normal mpg averaged over all driving is about 34mpg - but this includes a fair bit of town/country road and very little motorway. When I have measured it on the motorway on a single run I can get around 48 mpg which I think is pretty good.

[Alex-avensis]

Hi Dave,

              that`s excellent for an auto I`d say. I wish mine would close to 48 :( 

[Konrad C]

You are getting a poor return because when I had my old 1.8 Mk1, I was getting 36+ mpg mainly town/city driving. It had higher figures on longer motorway driving. You have checked the tyre pressures? What does the car drive like? Mine had good low end torque but check the vacuum switch is connected and working properly. I had two issue with my vacuum switch. The first was when the level had disconnected. The car did not drive right. I had to find a way of fixing the connection so it did undo. The second issue, was I undid the vacuum hose to the switch so the valves did not close off properly. This affected the emissions as well as the performance. What I did to rectify that problem was to disconnect the pipe, move the leave to the inlet valves to a different position, then connect the vacuum pipe whilst holding the leaver. The car improved ever since.

You could try and pull the EFI fuse  to reset the ECU so ot relearns new settings.

Just another little thing to check and help improve the economy. 

[Alex-avensis]

Hi Konrad,

                 thanks for all those tips. I have bought a Haynes manual as you suggested, will there be a section on the vacuum switch that you mention ? Or is that something you came across yourself? I don`t that it does drive as it should, unless it is meant to be quite sluggish on acceleration. The year before last it almost failed mot on emissions but I thought that was because the guy who changed the oil, over filled the sump.

  I will check the Haynes manual tomorrow to read up on the vacuum switch. Thanks again Konrad.

[fastbob72]

Hello there, it actually depends on which version of the 1.8 mk1 Avensis you have. Well, no sorry what I mean is both versions should give a similar mpg but it will depend on which version as to. how you go about finding or sorting out any issues.

My mk1 is the later 1.8 vvt-i where as the version Konrad had was the one with the 1.8 7A-FE engine.

I use mine daily getting back and forward to work which combined is 40 miles with at least 30 miles of that being on A roads and dual carriageway and the rest in the city.

Over the last year I was getting around 37mpg overall until I tried to cure it's constant emmisions fault for the MOT some 6 or 7 weeks ago.

With first one then both front precat o2 sensors disconnected it had 0 effect on performance but my mileage increased to 40mpg and now with new sensors, a new cat and no emmisions faults I get 40-42 mpg overall.

I would add I'm not particularly famous for my light, dainty right foot so if I tried to I'm sure I could get a couple more miles per gallon but I'm more than happy with hitting 40+.

I have to say for once Konrad's reply isn't as instantly clear as I've come to expect though that could be my lack of understanding.

I assume the vaccum switch refers to the Evaporative Emmisions Control system which is operated by a BVSV (Bi-metallic Vaccum Switching Valve) on the 7A-FE engine which is mounted on the cylinder head and a VSV (Vaccum Soleniod Valve) on the 1ZZ-FE vvt-i engine mounted on the air cleaner along with the AT sensor.

The BVSV is in part mechanical relying on a temperature triggered bi-metallic spring using coolant as the trigger for switching so therefore will have a certain scope for repair or adjustment where as the VSV is operated at the whim of the ECU with much less if no scope for fixing beyond straight replacement.

Obviously,check the vaccum hose on either version of the 1.8 to see if it's perished or damaged,is split anywhere or insecurely fitted.

Certainly you were right to expect a return of 37-40 mpg and higher on mostly long runs. I was getting nearly 48 mpg on a long run till I hit Edinburgh which the proceeded to slay that figure in minutes.lol.

As for how the car performs, judging acceleration is quite subjective really. The 1.8 Avensis isn't a high performer but both versions should pick up nicely.

The 7A does produce good low down torque but so does the 1ZZ the difference being the 1ZZ-FE really picks up noticeably better over 4000 rpm and above down mostly to the variable valve timing (or variable valve overlap in fact) but either way it should have a strong pulling engine at least if not exactly sporting.

The fact it nearly failed the emmisions test in the last before previous MOT is intriguing.It would need to be significantly overfilled with oil to be the cause but if it's result in the last test were better than the one before then it would suggest the cause was down to something else rather than engine condition like spark plugs,filter, even a vaccum leak.i.e something adjustable or replaceable because something like piston rings would only deteriorate more between tests and the result in the emmisions would have been even worse.

As Konrad suggested check the Vaccum Switch and all the hose connections between it and the manifold but also I'd strongly suggest checking the Crankcase Breather/Ventilation System in particular aswell because the blow by gases are piped into the inlet manifold/throttle body aswell so allowing another point for excess air to be drawn into the intake making your engine run leaner.

You mentioned new plugs and filter but have you tried replacing the HT leads at all.It will matter greatly here which engine you have as the 7A has normal HT leads where as the 1ZZ uses seperate coil packs per cylinder which can be prohibitively expensive to replace if you aren't sufficiently sure they are at fault. It's surprising, or I have found it so over the years what problems an old or faulty set of HT leads will cause and the difference replacing them makes.It's so often overlooked by many people for some strange reason as well.

It could be drawing in air in a number of different places around the engine,around the inlet manifold,any number of vaccum hoses,throttle body,idle stepper control valve amonsgt others but wherever it's getting in it'll lean out the mixture which will, paradoxically you may, think cause an increase in fuel consumption.

One cheap and easy way to check is with the engine idling spray a little ether around the areas of the inlet manifold, throttle body etc, etc. If there is a leak then the ether will be drawn in and cause the rpm to suddenly increase. You can buy a tin of ether at Halfords cheaply it'll be called Easy Start or something similar.

Also pulling EFi fuse or disconnecting the Battery for a few hours will reset the ECUs settings back to stock allowing it to relearn from your present sensors output.

Also, the areas in the Haynes manual would be the section on Emmisions Control...... Chapter 4B.

 

 

 

 

[Alex-avensis]

Quote

Hi Bob,

           and thanks very much for your comprehensive reply. There is a lot of info there, I will need to digest it and try and act upon it when I have some free time. My car is the early model,7A engine. On a quick inspection the vacuum switch (flying sourcer thingy) looks ok the hose leading from it seems intact with no wear or cuts of any kind. Will report back after I`ve had a play around.

                                                                                              Many Thanks,

                                                                                                          Alex.