2009 Scion tC fluctuating after putting gas in
10-21-2016, 01:57 PM
#1
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2009 Scion tC fluctuating after putting gas in
I have a 5 speed 2009 Scion tC, and whenever I fill it with gas the RPM's will fluctuate at idle and while driving. It just recently started doing this. It will fluctuate between 200-500 rpm. It makes driving and switching between 1st and 2nd a little bumpy sometimes due to the fluctuation. It fluctuates for about 5-10 minutes and then won't do it again until I put gas in again.
Last edited by MR_LUV; 10-04-2017 at 12:54 PM. Reason: typo
10-21-2016, 05:01 PM
#2
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I have a 5 speed 2009 Scion Tc, and whenever I fill it with gas the RPM's will fluctuate at idle and while driving. It just recently started doing this. It will fluctuate between 200-500 rpm. It makes driving and switching between 1st and 2nd a little bumpy sometimes due to the fluctuation. It fluctuates for about 5-10 minutes and then won't do it again until I put gas in again.
Sounds like the evaporative emissions controls. When filling up the vapors in the tank get compressed as the liquid gasoline flows in. That vapor gets pushed off into the charcoal canister via a valve. I'm thinking that the valve is not releasing the pressure in your gas tank when you fill up. Should probably have a dealership (unless you have the obd2 scanner that can activate tests via the computer) and have them test the evap controls. I'll bet that is what the problem is.
As it goes away over some time shows to me that the controls are a little "slow" and probably are close to finally failing when the CEL (check engine light) comes on.
10-29-2016, 01:39 PM
#3
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Sounds like the evaporative emissions controls. When filling up the vapors in the tank get compressed as the liquid gasoline flows in. That vapor gets pushed off into the charcoal canister via a valve. I'm thinking that the valve is not releasing the pressure in your gas tank when you fill up. Should probably have a dealership (unless you have the obd2 scanner that can activate tests via the computer) and have them test the evap controls. I'll bet that is what the problem is.
As it goes away over some time shows to me that the controls are a little "slow" and probably are close to finally failing when the CEL (check engine light) comes on.
As it goes away over some time shows to me that the controls are a little "slow" and probably are close to finally failing when the CEL (check engine light) comes on.
12-01-2016, 01:00 AM
#4
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Well I've previously had a check engine light earlier this year for EVAP, and I replaced the gas cap and it hasn't been back since. I know the Tc's have a CEL system where it has to detect the problem in multiple drive cycles, so would that prevent me from getting the CEL because it only happens when I fill up?
didn't see this message in my email until now! wow.. the answer is that the tC's do have an evaporative emissions system that checks for leaks, about 4-5 hours after the car turns off, it's above 40 degrees, etc.. If the problem only happens when you fill up, then the check valve in the gas tank that allows the evap charcoal canister to absorb the vapors being displaced by filling up, it's not working properly. That would cause issues with filling up.
But if you replaced the gas cap and the check engine light disappeared then you found the issue. But if you're saying the CEL comes back when filling up, then my first paragraph answers why.