LS430 high rpm on start-up

[jeremy156]

Curious whether my LS430 is behaving normally... when starting the engine I typically see 1200-1500rpm for a minute or two, falling to a more realistic 600-700 once warmed up.  Is that what others see, or do you have idle fall fairly rapidly after start on a cool (not cold) day?

Thanks,
Jeremy

[Las Palmas]

Had a Honda Accord coupé that did the same.

Great car.

[cruisermark]

I'll check and reply back but it wont be till tommorrow

[steve2006]

It sounds about right and the same as mine, idle is 650 RPM +/- 50 when fully warmed up.

[jeremy156]

Thank you.  Yes the 6-700rpm feels right when warm.  What I'm most curious about is the length of time it takes to settle down to that level.  Presumably it's by design, but the "lurch" into gear and urgency of the creep when releasing the brake pedal feels less than relaxed.

[steve2006]

Mine is similar regarding what I call “transmission jolt” when cold, takes around 4 minutes to reach “normal” on temperature gauge at fast idle but less if immediately driven. The transmission fluid also takes time to warm up, the temperature is also monitored and top gear will not engage until fully warmed up.

Once everything is toasty there is no transmission snatch and changes are only noticeable from the RPMs dropping.

[cruisermark]

Here is mine first cold start

 

[Sundance]

I'm told that high revs on start up is typical for Japanese models.  Takes a bit of getting used to but is neither unusual or abnormal (apparently!). 🙂

[ColinBarber]

Yes it is normal. Fast idle is used to raise engine temperatures quickly to improve overall emissions.

[royoftherovers]

3 hours ago, Sundance said:

I'm told that high revs on start up is typical for Japanese models.  Takes a bit of getting used to but is neither unusual or abnormal (apparently!). 🙂

Yep, Sundance, it is a regular feature on my wife`s Mazda 2.

[jeremy156]

22 hours ago, cruisermark said:

Here is mine first cold start

 

Thank you for taking the trouble to record this, appreciated. 
 

I’m grateful for all your replies and glad this is normal behaviour. I have just been through replacing bad vacuum lines and an exhaust leak, so with a smoother running engine it’s good to know this high idle is by design. 
 

jeremy

[MLW]

Sounds about the same as mine. You could have a look inside the throttle body and if it looks gungy, give it a clean with the correct spray fluid. Would do no harm anyway.