First Cold Start Of Day Needs Accelerator For 2 Minutes To Idle

[Decal]

Hi,

Not sure if I've posted this in the right forum firts post ,but an avid reader of these forums I've learnt loads about LS400's here.

When I start my LS400 1990 first thing in morning it won't idle until I have held the acceleartor done for 1-2 minutes and then idles perfectly and starts fine for the rest of the day .

I have tried searching through the forums but haven't found anything similar.

Thanks for a great forum .

Decal

[steve2006]

Hi and welcome to LOC,

I would think a problem with the cold start fueling, possibly the temp sender unit giving false readings to the ECU and telling it the engine is warm so the mixture would be too weak when cold or throttle body problem but I think this causes problems hot or cold engine.

No doubt someone with greater experience than me will be along later but looks like I've got home 1st today.

Cheers.

[Decal]

Thanks Steve,

I'll get that checked out

Decal

[Mat]

hey

would the oxy sensors have nothing to do with this problem?

[chips229]

Hi and Welcome to LOC :)

It might be worth cleaning the throttle body of the car and the PCV valve.

http://www.misterfixit.com/pcvvalve.htm

Theres pictures arent showing on the second link on my computer

http://www.lexusownersclub.co.uk/knowledge...;id=181&c=7

Hope that helps.

Let us know if that fixes it.

Chips.

[fatpieman69]

I don't know about the lex but on older jap cars there is a throttle position sensor that can do this but it genrally makes the revs go randomly up and then back down aswell.

craig

[steve2006]

hey

would the oxy sensors have nothing to do with this problem?

I don't think the oxygen sensors are active from a cold start due to a richer fuel mixture causing false readings.