Ls400 Hard To Start When Cold

[IS400]

My 1990 LS takes two cranks of the starter to come to life when it sits enough to cool off. During very hot days it starts on the first crank. Is there a sensor or solenoid that adds extra fuel when it is cold? Other than this, the engine runs perfectly for its age.

[IS400]

C'mon guys. Someone must know of a sensor or injector for cold starts on an LS400.

Here is what these cold starts are doing to me!

Each time it takes two cranks to start. Both my own temperature sensors turn on!

[SKperformance]

Start by sea foaming it.

Sounds like the throttle is sticking and not chocking the engine.

[IS400]

Start by sea foaming it.

Sounds like the throttle is sticking and not chocking the engine.

What is sea foam? Is is sprayed in the intake or put in the fuel tank?

Thanks for your reply btw.

[steve2006]

Hi,

I would start by checking the coolant temperature sensor and it's wiring, as the fault appears temperature related,if this is playing up it can make the ECU think the engine is warmed up when infact it is starting from cold so the cold start circuit does not come into operation when it should.

These sensors do fail and are not expensive to replace.

[IS400]

Steve,

Thanks for the ideas. I was looking around as you stated and did not find any frayed wires etc. I did find a vacuum line that was broken though. It comes from the power steering pump and tees at the intake. I capped it off and put a screw in the hose to keep dirt out of it. The engine rpm immediately dropped and ran smoother at idle. I have yet to try it cold again since I just finished the patch job. I'll keep you posted!