Corolla 2011 poor fuel economy

[schnoots144]

I bought a zre152r corolla and have been experiencing poor fuel economy with it, almost as high as 14.4l/100km as what the little screen reports. It is auto, and there are no error codes when scanned with an obd2 reader. I have noticed every now and then but definitely not often that when i'm stopped at lights the idle drops below 1000rpm and the car shudders for a bit. Aside from that acceleration is excellent and it takes off well. Large majority of my driving is within the suburbs and I don't even give it the beans.

 

When filling up to almost a fuel tank but still 2 bars below I get a tank distance of 302km which is abysmal for a corolla, I genuinely think my aurion is doing better on fuel than this thing is. What should I take a look at under the bonnet in regards to fixing this? I've disconnected the battery and let it sit for a day to "reset" but that really didnt do much. Tyres are at 36 psi and its recently had an oil change. All other fluids were flushed and at their max level.

 

Would appreciate any insight as to how I can get things fixed. Cheers

[ozieagle]

My first thought was a fuel leak. Cracked hose(s), after the pump, or weeping joins.

 

Herb

[schnoots144]

5 hours ago, ozieagle said:

My first thought was a fuel leak. Cracked hose(s), after the pump, or weeping joins.

 

Herb

Cheers for the reply Herb, all the hoses in the engine bay and under the car are dry as can be, clamps are tight and no cracks. Haven't lifted the rear seats to check the pump, car never makes a smell either. Are there any notable readings I can look at with an obd2 reader to check if anything is not working right? I was thinking of cleaning the TB and running liqui moly gas system cleaner to see if that helps. I should add that its being run on 91 

Edited February 12 by schnoots144

[ozieagle]

Hi John,

 

Sorry I can't answer specifics, as I'm a classic British car freak, and my answer was the sort of thing I would check in my cars.

 

With a Corolla I would expect a fuel economy less that 10l/100km

 

P.S. why I'm on this forum is that I have a 1995 Hi Ace camper.

 

Herb

Edited February 12 by ozieagle

[CB3109]

Have you pulled out the spark plugs to see if they have a story to tell?

What about a compression check?  Handbrake not binding?  Wheel bearings OK?

 

[campbeam]

My first thought would be to start with checking the air filter and determine whether it needs a cleaning or replacement. Next thoughts are to check/clean the MAF [mass airflow sensor] throttle body and the IAC [idle air control] valve.

This YouTube video may be of some assistance.

 

[schnoots144]

2 hours ago, CB3109 said:

Have you pulled out the spark plugs to see if they have a story to tell?

What about a compression check?  Handbrake not binding?  Wheel bearings OK?

 

I'll check the plugs when I can, have yet to do that. Previous owner claimed to have changed them, handbrake is fine, wheel bearings dont grind and havent done a compression check (don't have the tool for it)

34 minutes ago, campbeam said:

My first thought would be to start with checking the air filter and determine whether it needs a cleaning or replacement. Next thoughts are to check/clean the MAF [mass airflow sensor] throttle body and the IAC [idle air control] valve.

This YouTube video may be of some assistance.

 

I followed this today and cleaned the TB while it was still in the car, it was extremely dirty inside and on the rim of the throttle plate but almost mirror clean on the outside, looked like a half ****d job. Didnt look at cleaning the IAC however, can it be pulled off the TB separately or do I have to take the whole TB off in order to get it off? Air filter is also not super dirty either has a date code of 2021 and is only slightly dark, MAF was cleaned a few weeks ago.

Next job is to look at the plugs, and run a test with what i've done so far

[Novicebutnice]

On 2/11/2024 at 3:23 PM, schnoots144 said:

I bought a zre152r corolla and have been experiencing poor fuel economy with it, almost as high as 14.4l/100km as what the little screen reports. It is auto, and there are no error codes when scanned with an obd2 reader. I have noticed every now and then but definitely not often that when i'm stopped at lights the idle drops below 1000rpm and the car shudders for a bit. Aside from that acceleration is excellent and it takes off well. Large majority of my driving is within the suburbs and I don't even give it the beans.

 

When filling up to almost a fuel tank but still 2 bars below I get a tank distance of 302km which is abysmal for a corolla, I genuinely think my aurion is doing better on fuel than this thing is. What should I take a look at under the bonnet in regards to fixing this? I've disconnected the battery and let it sit for a day to "reset" but that really didnt do much. Tyres are at 36 psi and its recently had an oil change. All other fluids were flushed and at their max level.

 

Would appreciate any insight as to how I can get things fixed. Cheers

Hi,

As has already been pointed out,

Check the spark plugs (I would replace them anyway),

As an aside how well do you know the previous owner (do you have an accurate service history for the car), and what engine oil (brand, viscosity etc) did you use on the latest oil change.

The car shouldn't be idling at 1000 rpm when stopped at the traffic lights etc even in "Drive" let alone if you put it into "N" whilst waiting for the traffic light to change.....

What brand and type of fuel have you been using in your car?

To me it seems that the primary cause of the excess fuel consumption is more than likely related to high idle that you have noticed,

So I would recommend checking all of the air hose connections (both for the intake as well as vacuum hoses etc

As an aside have you noticed the brake pedal feeling harder to push than normal? after you turn off the engine how many times can you push the brake pedal before if feels rock hard (should be normally around 4-5 pushes)?

After "pumping" the brake pedal until it feels hard, push down on the brake pedal whilst starting the car, the pedal should "drop"

Then I would move on to checking the PCV, have you noticed if the car uses/ burns oil in-between services? and how often is the oil changed? (so that a time frame for the oil consumption can be worked out)

Let us all know how you go 🙂

Edited February 25 by Novicebutnice

[schnoots144]

On 2/26/2024 at 6:36 AM, Novicebutnice said:

Hi,

As has already been pointed out,

Check the spark plugs (I would replace them anyway),

As an aside how well do you know the previous owner (do you have an accurate service history for the car), and what engine oil (brand, viscosity etc) did you use on the latest oil change.

The car shouldn't be idling at 1000 rpm when stopped at the traffic lights etc even in "Drive" let alone if you put it into "N" whilst waiting for the traffic light to change.....

What brand and type of fuel have you been using in your car?

To me it seems that the primary cause of the excess fuel consumption is more than likely related to high idle that you have noticed,

So I would recommend checking all of the air hose connections (both for the intake as well as vacuum hoses etc

As an aside have you noticed the brake pedal feeling harder to push than normal? after you turn off the engine how many times can you push the brake pedal before if feels rock hard (should be normally around 4-5 pushes)?

After "pumping" the brake pedal until it feels hard, push down on the brake pedal whilst starting the car, the pedal should "drop"

Then I would move on to checking the PCV, have you noticed if the car uses/ burns oil in-between services? and how often is the oil changed? (so that a time frame for the oil consumption can be worked out)

Let us all know how you go 🙂

Hi novice, apologies for the late reply. I've got spark plugs on hand ready to change but havent done it yet, TPX019 tri power iridium plugs. 0 info online about them so i'd could use some clarification as to whether they're any good, seems to be a wesfil owned brand. Previous owner told me he had already changed the plugs along with the oil at the time of purchase (only got it in january this year) and he used toyota branded 10w-30 oil. What is the best viscosity for a 2zr anyways? I personally always use 5w-30 on all toyotas i've owned that call for it, but the manual even allows for 0w-20. After cleaning the throttle body I noticed a massive change in how the car idles, before it would drop to what seemed like only a couple hundred rpm and the whole car would shudder - it idles now before 1000rpm with no hesitation. Since I got it i've been filling it with 91 from wherever is cheapest be it metro or speedway etc. Only been about 2 times that i've even filled it, and never to a full tank just 30-40 dollars worth due to the obvious bad economy. Changed the air filter and cleaned the MAF too.

All the air hose connections are fine, tightly put on and the brake pedal is also fine, 4-5 pushes and its rock hard + drops when starting. I've been checking the dip stick every now and then and the level has not dropped a dot since purchase.

This tank now currently has 95 from metro and is mixed with liqui moly fuel system cleaner, i'm about 138ish km in and only 1 bar has dropped from full (levin zr digital gauge). I have high hopes that I may have fixed the issue and if not then the new plugs are going in.

 

Rundown of whats been done

- Cleaned TB

- Cleaned MAF

- New air filter

- Fuel system cleaner

- Almost brand new continental tyres at 36 psi

- Cabin air filter (irrelevant)

 

I noticed that I havent mentioned the full specs of the car - its a levin zr hatchback with a 4 speed auto with 153,000 ks

 

I will report back with my results after this tank is almost empty, cheers to all once again for the help

Edited March 3 by schnoots144