Fast Idle and Shifting

[Twiggles]

Hi! New to me 2011 LX570 with 115k miles. Well Maintained by dealer.

During cold start up it does fast idle as expected, then drops down to around 1000-1100 rpm, which is quite a bit faster than normal idle. When I shift during this "secondary fast idle" my RPMs climb about 200-300 rpm while shifting. Any ideas what might be going on? Is this typical on these? Additionally, not sure if this is connected or not, but there appears to be an ever so slight exhaust leak while cold which goes away when warm.

Once warm, idle is steady and normal, and shifting results in the expected slight RPM dip while shifting.

 

[AnyMal]

The exhaust might be the famous manifold crack leak. Rusty environment?

As far as the idle, I wouldn’t want you to mask anything, but if you feel like fooling around and finding out, you can try the idle reset procedure.

 

[Twiggles]

The exhaust might be the famous manifold crack leak. Rusty environment?

As far as the idle, I wouldn’t want you to mask anything, but if you feel like fooling around and finding out, you can try the idle reset procedure.

I plan on taking a look at the manifold, it's an Ohio LX, but basically rust free underneath. Thanks.

 

[E J Neil]

My 2008 LC200 does the same fast idle/rev/shift thing when cold. It's normal for a car to rev high when cold but mine seems to rev higher than I'd expect.

 

[TomEf]

The exhaust might be the famous manifold crack leak. Rusty environment?

As far as the idle, I wouldn’t want you to mask anything, but if you feel like fooling around and finding out, you can try the idle reset procedure.

Do you happen to have a reference for the idle reset procedure? Search didn't seem to turn anything up.

 

[AnyMal]

Do you happen to have a reference for the idle reset procedure? Search didn't seem to turn anything up.

Im sorry i do not, and tied up this week, try searching “toyota idle relearn” instead. Or “relearn idle”. And use google not MUD.

 

[TeCKis300]

Idle is usually programmed against coolant temperature as the primary factor. A high idle in open loop prior to warm-up is very normal and probably also related to emissions and the need to light off the catalytic converter. There is also mild idle-up for things like steering pump load and alternator loads.

@Twiggles , from your description, it all sounds normal. The 5.7L is a big motor on a big truck if what you're use to is smaller passenger cars that don't load up the torque converter at idle.

 

[AnyMal]

Idle is usually programmed against coolant temperature as the primary factor. A high idle in open loop prior to warm-up is very normal and probably also related to emissions and the need to light off the catalytic converter. There is also mild idle-up for things like steering pump load and alternator loads.

@Twiggles , from your description, it all sounds normal. The 5.7L is a big motor on a big truck if what you're use to is smaller passenger cars that don't load up the torque converter at idle.

Yeah but he should be dropping closer to 600rpm after initial start up idle program completes.
His staying at 1100 doesn't sound normal.

OP do you have the wheel fully clocked and everything inside on blast in freezing temps or something?
Bad steering pump? Do you hear any noises?

 

[TeCKis300]

Yeah but he should be dropping closer to 600rpm after initial start up idle program completes.
His staying at 1100 doesn't sound normal.

OP do you have the wheel fully clocked and everything inside on blast in freezing temps or something?
Bad steering pump? Do you hear any noises?

Guess I'm not so quick to jump to things are wrong. If there were exhaust leaks, or mechanical issues, modern ECUs are tyrannical in sensing and throwing CELs.

Cold idle is not singular that steps directly to hot closed loop operation. There's a progression through warm up. Sounds like the OP is describing something pretty normal that I have noted too, and he is just learning the car.

@Twiggles , if you really believe something is wrong, it's plausible it could be a vacuum leak type issue. Get yourself an OBD-II scanner and check the short term and longer term fuel trims. These should generally be in the range of +/- 10. That'll tell you if it deserves further exploration.

 

[Twiggles]

Idle is usually programmed against coolant temperature as the primary factor. A high idle in open loop prior to warm-up is very normal and probably also related to emissions and the need to light off the catalytic converter. There is also mild idle-up for things like steering pump load and alternator loads.

@Twiggles , from your description, it all sounds normal. The 5.7L is a big motor on a big truck if what you're use to is smaller passenger cars that don't load up the torque converter at idle.

Thanks for the info! I have had several cars/trucks in my life, but this is the first 200 Series. I am glad to hear this sounds normal for these.

 

[Twiggles]

Guess I'm not so quick to jump to things are wrong. If there were exhaust leaks, or mechanical issues, modern ECUs are tyrannical in sensing and throwing CELs.

Cold idle is not singular that steps directly to hot closed loop operation. There's a progression through warm up. Sounds like the OP is describing something pretty normal that I have noted too, and he is just learning the car.

@Twiggles , if you really believe something is wrong, it's plausible it could be a vacuum leak type issue. Get yourself an OBD-II scanner and check the short term and longer term fuel trims. These should generally be in the range of +/- 10. That'll tell you if it deserves further exploration.

My fuel trims could be a bit screwy because I removed the battery a few weeks ago. Its my understanding that those trims can be reset with battery removal. I'm pretty comfortable that my LX is acting "normal". Its just different than other vehicles I've owned.