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Problem, slow acceleration, high fuel consumption!

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SC430 - 2nd Gen (2001-2010)

Problem, slow acceleration, high fuel consumption!

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Old 05-28-18, 11:01 AM
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killerok
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Question Problem, slow acceleration, high fuel consumption!

Hallo everyone, sorry for my english, i am from russia. The SC430 became sharply after summer eating 20 liters per 100 km instead of 10-13 on summer. On the service swept with the computer, no passes, the injection is normal, reheats, changed the flowmeter, though not to a new one, it did not help, there is a sensor error of the stop signal on the pedal, I ordered it - I was waiting, I was also advised to change the thermostat. Who has any ideas, what else could be the problem?
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Old 05-28-18, 12:01 PM
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After reading forum i decide to change MAF, i'll reply after changing MAF and air filter. i order DENSO DMA0100
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Old 05-28-18, 12:35 PM
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Originally Posted by killerok View Post
After reading forum i decide to change MAF, i'll reply after changing MAF and air filter. i order DENSO DMA0100
you need to make sure the air ducts are tight and check all of the vacuum lines. They will break due to the age of the rubber hoses. They become brittle and split.

are there any codes from the OBDII computer?
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Old 05-28-18, 12:42 PM
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Originally Posted by Bgw70 View Post


you need to make sure the air ducts are tight and check all of the vacuum lines. They will break due to the age of the rubber hoses. They become brittle and split.

are there any codes from the OBDII computer?
thx for reply, what air ducks, can i see them? there are no codes OBDII on official dealer
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Old 05-28-18, 01:19 PM
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Originally Posted by killerok View Post
thx for reply, what air ducks, can i see them? there are no codes OBDII on official dealer
i am referring to the duct from the air filter box to the throttle body. Make sure the clamps are tight and nothing is broken. See pics. I also circled the areas where you should check the vacuum lines.

have the spark plugs ever been changed?
did the change in fuel usage change all at once?
did someone work on the car when this changed?

what year SC430 and how many kilometers on the car?


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Old 05-28-18, 01:40 PM
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Originally Posted by Bgw70 View Post


i am referring to the duct from the air filter box to the throttle body. Make sure the clamps are tight and nothing is broken. See pics. I also circled the areas where you should check the vacuum lines.

have the spark plugs ever been changed?
did the change in fuel usage change all at once?
did someone work on the car when this changed?

what year SC430 and how many kilometers on the car?




spark plugs - changed after problem begin, about 500 kilometers ago
did the change in fuel usage change all at once? - after last summer it starts with a cold weather (because of it i change thermostat)
did someone work on the car when this changed? - yes officials try to find a problem but cant, OBD - no mistakes, fuel momently stats is ok on left and right air sensors (lambda probe) are symmetrical

my car is 2004 with 90000 miles

now it is about 8 seconds to 100 km/h and 12 miles/galon in the city and 16 miles/galon - on highway (with A/C off)

Last edited by killerok; 05-28-18 at 01:43 PM.
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Old 05-28-18, 01:51 PM
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Originally Posted by killerok View Post
spark plugs - changed after problem begin, about 500 kilometers ago
did the change in fuel usage change all at once? - after last summer it starts with a cold weather (because of it i change thermostat)
did someone work on the car when this changed? - yes officials try to find a problem but cant, OBD - no mistakes, fuel momently stats is ok on left and right air sensors (lambda probe) are symmetrical

my car is 2004 with 90000 miles

now it is about 8 seconds to 100 km/h and 12 miles/galon in the city and 16 miles/galon - on highway (with A/C off)
did the change in fuel usage change all at once? - after last summer it starts with a cold weather
I think Putin lowered the Octane rating! LoL, just kidding...

are you running premium fuel?

i modified my exhaust on my 2002, removed the resonators and third cat and believe that lowered the fuel mileage. I get 20 MPG average on the 2002 but my 2007 gets 24 average. AC is on.
I run 91-93 octane.




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Old 05-28-18, 02:18 PM
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Originally Posted by Bgw70 View Post


did the change in fuel usage change all at once? - after last summer it starts with a cold weather
I think Putin lowered the Octane rating! LoL, just kidding...

are you running premium fuel?

i modified my exhaust on my 2002, removed the resonators and third cat and believe that lowered the fuel mileage. I get 20 MPH average on the 2002 but my 2007 gets 24 average. AC is on.
I run 91-93 octane.




are you running premium fuel? - yes in russia we use 95 octane fuel shell v-power
"I get 20 MPH average on the 2002 but my 2007 gets 24 average" - you mean that older car use less(lower) fuel? ))))))))))))

you think that changing MAF and air filters will not solve my problem?
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Old 05-28-18, 02:58 PM
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Originally Posted by killerok View Post
are you running premium fuel? - yes in russia we use 95 octane fuel shell v-power
"I get 20 MPH average on the 2002 but my 2007 gets 24 average" - you mean that older car use less(lower) fuel? ))))))))))))

you think that changing MAF and air filters will not solve my problem?
i donít think that changing your MAF will correct the problem, at this time...if your air filter is dirty then change it, but I donít think you would have a dirty air filter.

you need to check the easy cheap items first instead of ordering parts.

my fuel mileage is the opposite of yours...I get 20 miles per gallon of gas in my 2002, or 8.5 Kilometers per liter in my 2002.
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Old 05-28-18, 03:07 PM
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Originally Posted by killerok View Post
Hallo everyone, sorry for my english, i am from russia. The SC430 became sharply after summer eating 20 liters per 100 km instead of 10-13 on summer. On the service swept with the computer, no passes, the injection is normal, reheats, changed the flowmeter, though not to a new one, it did not help, there is a sensor error of the stop signal on the pedal, I ordered it - I was waiting, I was also advised to change the thermostat. Who has any ideas, what else could be the problem?
I had twice the mileage issues, both had easy solutions. Once the tires pressure was low (20 psi?) and once a vacuum hose was out
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Old 05-28-18, 03:52 PM
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Originally Posted by Prasha View Post
I had twice the mileage issues, both had easy solutions. Once the tires pressure was low (20 psi?) and once a vacuum hose was out
tyres are new 240/45/18 with 2.2 bar pressure
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Old 05-28-18, 03:54 PM
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Originally Posted by Bgw70 View Post


i don’t think that changing your MAF will correct the problem, at this time...if your air filter is dirty then change it, but I don’t think you would have a dirty air filter.

you need to check the easy cheap items first instead of ordering parts.

my fuel mileage is the opposite of yours...I get 20 miles per gallon of gas in my 2002, or 8.5 Kilometers per liter in my 2002.

when my car have no problems it was 17 mph in the city and 20 mph on the highway, at one time it sharp 12/16

I noticed that the slow acceleration in 1-2 gears, the 3.4.5 dynamics remained normal!
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Old 05-29-18, 03:44 AM
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Originally Posted by Prasha View Post
I had twice the mileage issues, both had easy solutions. Once the tires pressure was low (20 psi?) and once a vacuum hose was out
makes me wonder if his PCV valve is stuck open. That would be a vacuum leak.
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Old 05-29-18, 06:43 AM
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Originally Posted by Bgw70 View Post


makes me wonder if his PCV valve is stuck open. That would be a vacuum leak.
where can i see PCV?
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Old 05-29-18, 07:42 AM
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Originally Posted by killerok View Post
where can i see PCV?
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

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