Starting Issues Only When Cold

[SargeRX8]

Got an r33 which fails to start first time when cold. It will turn over, fire, splutter then die. Alot of reading states the following. Cold start valve, water temp sensor, vacuum leak.

Question is which water sensor do I need? They say it's a water temp switch which controls the auto choke on cold or some shit. Is it the blue one or completely brass one?

Is it possible to clean the cold start valve?

I will be conducting a intake test this week under 18psi.

Info is much appreciated.

[89CAL]

Have you got a power FC + hand controller? I don't quite remember.

If so what does the water temp read like from start till when it's warm?

[SargeRX8]

17degrees cold to 79 - 82c warm. Power FC and what not both operate fine. Its weird that on first start it won't start, second start is perfect. Google search skyline wont start first time there is a whole crap load of results. Some people say the CSV and some say the water temp switch. Others say vac leak.

From what I have read, though, the dash temp sensor and the number shown on the power FC are DIFFERENT to the sensor which is used to determine other shit. There are two water temp sensors apparently... One just to show the number, the other to control the car.

Also can't find the cold start valve. People say on the R32 its above injector 4 and 5 and should be the same on the RB25. There is nothing there.

[75coupe]

goto the sensor check on the hand controller and see if the water temp sensor is working before you start the car when cold... Ive had the sensor fail before but it work fine once warm...

[89CAL]

So first start at say 17 degrees C it wont start, then immediately after it starts? Or when you say second start do you mean after its been started and running before. If so what temp is it at then?

I wouldnt assume it would be something in the tune, I've never touched all the water temp correction etc stuff on mine, and as far as I know these dont need to be altered from the base tune that often.

Cold start valve.... I've never really had much experience with it, but perhaps it is the problem. I'm pretty sure that the cold start valve has coolant running through it and then has an electrical plug out of it, but I'm not sure if this goes back to the ECU or just to the AAC valve. The water temp sensor near the thermostat is the one your Power FC HC is seeing, and pretty sure this is where it gets alot of the timing and fuel mixtures from for the cold start. Im just wondering if maybe the Cold start valve is controlling the AAC valve and its not working and your getting not enough air for the extra fuel the ECU is injecting.

this is all just guess work on the Cold Start Valve but.