Problem, slow acceleration, high fuel consumption!
05-29-18, 01:56 PM
#16
Driver School Candidate
Do you understand when I say check the vacuum lines for cracks?
click the link below and read this thread about the PCV valve. You should have the screw in type found on the 2004-2010 SC430s
https://www.clublexus.com/forums/sc4...pcv-valve.html
05-29-18, 02:15 PM
#17
Then I remember it took few days of driving to notice the change/difference.....(my memory is weak)
05-29-18, 04:03 PM
#18
Driver School Candidate
Thread Starter
Do you understand when I say check the vacuum lines for cracks?
click the link below and read this thread about the PCV valve. You should have the screw in type found on the 2004-2010 SC430s
https://www.clublexus.com/forums/sc4...pcv-valve.html
05-29-18, 05:40 PM
#19
Lexus Test Driver
((((((((((((
07-11-18, 02:23 PM
#21
Pole Position
If your gas mileage is that low, there must be a code in the computer.
Please take your car to another place to have it scanned.
Or buy one of these scanners from China off ebay https://www.ebay.com/itm/NEW-Scanner...YAAOSwBgVa4ZK-
Are there any other problems?
Please take your car to another place to have it scanned.
Or buy one of these scanners from China off ebay https://www.ebay.com/itm/NEW-Scanner...YAAOSwBgVa4ZK-
Are there any other problems?
07-11-18, 02:24 PM
#22
Pole Position
I guess you could also be having trouble with your transmission, which is why a non toyota code reader isn't showing any codes.
07-11-18, 03:36 PM
#23
Driver School Candidate
Thread Starter
i check my car on dealer they have original OBDII and no problem codes, they said that mix of gasoline and air is good too and there is no mistakes in moment consumption ... i dont know what else can be ... may be change dealer ...
07-11-18, 04:57 PM
#24
Causes of low fuel mileage.Possible o2 sensor
O2 sensor bias They are working but weak and will tend to read on the lean side fooling the computer to add fuel.
the O2 sensor measures the oxygen content of the exhaust. The O2 sensor’s sensing ability comes about by producing a small voltage proportionate to the exhaust oxygen content. In other words, if the oxygen content is low it produces a high voltage (0.90 Volts - Rich mixture) and if the oxygen content is high it produces a low voltage (0.10 Volts - Lean mixture). Although theoretically, the O2 sensor should cycle between 0.00 volts and 1.00 volts, in reality, it cycles between 0.10 volts and 0.90 volts
A qualified mechanic can look at the data and tell if the sensor is Bias and needs replacing.
Think of the O2 sensors in your car like a 9-volt battery It still works well below 9 volts just not like it did when new.
Another thing to check is the thin heated wire in the MAF sensor. The sensor works by sending voltage across a thin wire and heating it up. As air flows across the wire and cools it down a signal is created that the ECM uses to determine the air flow rate. That wire needs to be cleaned almost as often as you change your oil. If you use an air filter other than OEM you will more than likely get oil on the wire and mess up the data. .
O2 sensor bias They are working but weak and will tend to read on the lean side fooling the computer to add fuel.
the O2 sensor measures the oxygen content of the exhaust. The O2 sensor’s sensing ability comes about by producing a small voltage proportionate to the exhaust oxygen content. In other words, if the oxygen content is low it produces a high voltage (0.90 Volts - Rich mixture) and if the oxygen content is high it produces a low voltage (0.10 Volts - Lean mixture). Although theoretically, the O2 sensor should cycle between 0.00 volts and 1.00 volts, in reality, it cycles between 0.10 volts and 0.90 volts
A qualified mechanic can look at the data and tell if the sensor is Bias and needs replacing.
Think of the O2 sensors in your car like a 9-volt battery It still works well below 9 volts just not like it did when new.
Another thing to check is the thin heated wire in the MAF sensor. The sensor works by sending voltage across a thin wire and heating it up. As air flows across the wire and cools it down a signal is created that the ECM uses to determine the air flow rate. That wire needs to be cleaned almost as often as you change your oil. If you use an air filter other than OEM you will more than likely get oil on the wire and mess up the data. .
Last edited by Goldwinger; 07-11-18 at 05:00 PM.
07-11-18, 05:03 PM
#25
By that last statement I mean that non-original air filter has oil on the paper that will work its way on the sensing wire of the MAF meter and over time the oil collects dirt and the dirt acts as insulation and the MAF is not sending crap for data.
I would also check the fuel pressure to make sure it's correct.
I would also check the fuel pressure to make sure it's correct.
07-12-18, 02:35 AM
#26
Driver School Candidate
Thread Starter
By that last statement I mean that non-original air filter has oil on the paper that will work its way on the sensing wire of the MAF meter and over time the oil collects dirt and the dirt acts as insulation and the MAF is not sending crap for data.
I would also check the fuel pressure to make sure it's correct.
I would also check the fuel pressure to make sure it's correct.
07-12-18, 04:03 AM
#27
The front o2. Both one on each side of the engine. The front ones control the fuel injector pulse. The rear do nothing except monitor, They have the lazy job of just watching the exhaust gas come out of the converter and have no input on performance. The front does all the work.
07-12-18, 07:55 AM
#28
Two thoughts come to mind for me. One, is one of the brakes dragging. Two, is the computer staying in open loop, because the coolant temperature sensor isn't working correctly. That makes more sense to me after everything that has been checked already. If the O2's were responding so slowly as to loose six or more Mpg's it would have thrown a code for slow response. I've had pending code for slow response, and was only getting about a 1 mpg loss.
Last edited by Coleroad; 07-12-18 at 08:01 AM.
07-12-18, 10:28 AM
#29
Pole Position
I had this same thought when I was driving home last night.A dragging brake is a purely mechanical part that would not throw a computer code.
Try pushing down your parking brake all the way and then use the release handle to take the brake off. It is possible that the brake was slightly pushed in, but not enough to trigger the brake light on your dash.
If it is not that simple, then you should have your brakes inspected to see if one of them doesn't release all the way.
Try pushing down your parking brake all the way and then use the release handle to take the brake off. It is possible that the brake was slightly pushed in, but not enough to trigger the brake light on your dash.
If it is not that simple, then you should have your brakes inspected to see if one of them doesn't release all the way.
07-12-18, 11:07 AM
#30
Lead Lap
If the brakes are dragging, you should feel excessive heat coming through the wheels from your brakes after driving. You'll normally feel some anyway but it would be above normal.