Jump to content
The mkiv Supra Owners Club

Changed 02 sensor still thirsty as hell!


Thomas.B

Recommended Posts

Ok so I have changed the 02 sensor and the sparkplugs (also the oil, oilfilter, diff-oil and Autobox oil).

 

Still the car seems way to thirsty, was driving very moderate with only 1-2 overtakings other then that kept to about 60 and some driving in town.

 

Came 28.3 miles and filled up with 9,45 liters of gas. It comes to just above 2liters/10-km or 0,4liters every Mile.

 

Is this normal?

It should be a Jspec and only have 1 o2-sensor right? I was going to put the cat back on for the MOT and found another sensor looking like an 02 sensor, this was just put up out of the way with wire.... could this be the issue?

 

Image is found here (http://www.imageupload.org/?d=1AF603E11) big picture so dont want to link it in.

 

If this is an extra 02 sensor, can I work around this so the ECU wont get more readings from it?

Edited by Thomas.B (see edit history)
Link to comment
Share on other sites

I was going to put the cat back on for the MOT and found another sensor looking like an 02 sensor, this was just put up out of the way with wire.... could this be the issue

 

Image is found here (http://www.imageupload.org/?d=1AF603E11) big picture so dont want to link it in.

 

If this is an extra 02 sensor, can I work around this so the ECU wont get more readings from it?

 

Looks like the Cat sensor. I've tucked mine out of the way too :)

Link to comment
Share on other sites

Looks like the Cat sensor. I've tucked mine out of the way too :)

 

Ok so nothing that is needed for any function? I can just weld the hole in the cat for it?

 

But still, any ideas on what is causing it to drink so f-ing much fuel?

Link to comment
Share on other sites

Works out 13mpg? thats not normal, worse than the black beast:d

 

Exacty, and for only being a full BPU Im not very impressed :D

 

Could it be the whole ECU that needs changing?

Before I changed the o2 sensor I only came 130miles on 65-70£ (gas is 1.40£/liter) so somewhat better now but still sucks. Was thinking of driving it to see some friends far from me when my vacation starts in 2 weeks so would be nice to fix whatever is wrong....

 

When resetting the ECU, should I drive away directly? Or does it need any certain way of driving to set itself? Not that I think it'll help to reset again but worth a shot maybe....

It does pull strong, maybe abit slower then what I would like until it hits boost.

Link to comment
Share on other sites

pull the ecu fuses then drive for approx 50 miles for the ecu to relearn

 

I disconnected the battery for 15-20min and then had it on idle for 5-10min and drove for a couple of miles.

Would this really matter? Might it drink less petrol for every mile I drive? As it is somewhat lower now.

If this is the case that would be really strange and everytime the battery gets low youll have to drive 50miles to get it to be normal...?

Strange that the ecu is so ancient when everything else seems to be very "high-tech" for its age.

Link to comment
Share on other sites

Have you got any of your brakes binding on ,as i was getting low mpg and my brake were sticking on . Rich.

 

"Sadly" all weels are easy to push around by hand.

I am really clueless as to what it can be and it pisses me off :(

Could the ECU be bad? Any ideas or maybes? It does not leak any gas as the fuelpump does not load anything (after the first load) when having the key on and its clean underneath.

 

I really need it fixed before the MOT as the values will be completely off....

Link to comment
Share on other sites

I had the very same problem. 10-15mpg. I changed the o2 sensor, reset the ecu and drove 60 miles of varied driving in one turn. Now getting 24+.

 

Toyota or aftermarket sensor?

 

When the car is at idle go to the passenger side and stick your nose under the sill and see if you get a strong smell of fuel. Cars are getting on and fuel lines can and do rot and go porous.

Link to comment
Share on other sites

Measure the output voltage from the MAP sensor at idle and at cruise and post the results. Check the MAP sensor hose and anything that has been T'd off it have no splits or leaks. Has it got a new thermostat in it? If it runs too cool it will use a lot more fuel. You need a good garage to check all the sensor outputs.

Link to comment
Share on other sites

Dont think the thermostat can make it drink double the amount it should. Also it drank more before I started the change (before 2.5liters/swedish mile, now 2).

 

If the mapsensor is bad then it shouldnt run so good and I would have trouble getting good boost. I get 1.2bar without hesitation.

 

I have booked a time to get a error-code search if I cant find the problem myself.

Link to comment
Share on other sites

If the MAP sensor is outputting the wrong voltage for the pressure / vac applied, or the pressure / vac signal source has a leak, it could well over fuel, yet still give pretty normal boost and good power. Also if the t/stat is opening too soon a low engine temp will have it running on a rich part of the map. Again, pretty normal boost and power, but bad economy. The only way to see is to measure resistance of the ecu water temp sensor and voltage from the MAP sensor.

Link to comment
Share on other sites

  • 1 year later...

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.

Guest
Reply to this topic...

×   Pasted as rich text.   Restore formatting

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

×
×
  • Create New...

Important Information

We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue. You might also be interested in our Guidelines, Privacy Policy and Terms of Use.