R33 Rb25Det Wont Start First Time When Temp At 17C Or Below

[SargeRX8]

I had an old thread but I have NO idea where its gone. Anyway I have found the definitive cause to my problem but yet to find a solution.

When I go to start the car early mornings or late nights, it sometimes starts and sometimes doesn't. But I can now safely say that the car will ONLY not start if the temperature reading(water temp) on my pfc handcontroller is at 17C or below. 18C it will start. 17c, start, bog down and die then start fine second time. 16C same as 17c and so on. 18c, 19c, 20c the car is fine.

What the f**k could it be? Nothing in my tune is set to any type of correction at 17c... I have no vacuum leaks as I done an intake pressure test and its all tight and sealed. The main things I read are cold start valve, water temp sensor and vac leaks. I rule out vac leaks. I have no idea where the cold start valve is on the R33(Ive cleaned the AAC, didn't do squat). Water temp sensor, there are two Ive heard, I don't know which one to change.

Water temp sensor always shows 3.4~ give or take .2, .3 when the car is on ignition so I think its still working but I can't say for sure.

The car takes 24degrees of timing to start. I have noticed on my old tune it took 42 degrees of timing to start(from a cold start to get the car to idle, pfc showed 42 degrees max now its 24). Does this have any effect?

[central coast person]

It could be so many thing its to hard to say what it is over the net.

I had the problem with my leaky injectors that gave that lumpy start and stall in cold mornings then second start was like a brand new car(fuel presure regulator has the exact same symptoms). My friends car did the same thing but the fuel pump was not holding pressure after 8 hours and air would get into the fuel lines and if your primed the pump it would just confuse you more because the air bubble would stay in the fuel piping causing us to think it was somthing else.

If you want to try at temp sensor change the temp sensorwith 2 pins. Its not to for from your top radiator hose and you will see a single pin sensor for your temp gauge also side by side. The only one that you need to change is the 2 pin one as the other one only is a signal for the cluster in the dash. They are cheap, around $70.

[SargeRX8]

I can leave the car off for 3 days and start it up just fine if the temp is above 17c. Sometimes it can cool quickly, 3 hours to below 17c and then it wont start first time which leads me to believe it isn't leaking injectors(brand new nismo 740cc's with new o rings and seals etc).

Its a brand new fuel pump in there, a 040. I'm going to whack in a new temp sensor when I get my hands on it see what happens.

[SargeRX8]

f**king shit f**k, my theory just got thrown out the window. Power FC showed 24C, car started and then bogged down then started fine.

The car was doing this when it was stock as a rock and still doing this with all mods(new injectors, turbo, ecu, afm, fuel pump etc).

[Daleo]

On my old RB30 powered R31, it would do basically what you are describing on the first start; stall, then hit the key again and it's fine.

I replaced the battery; started first time, every time. 5 years later when it started doing it again, replaced the battery; started first time, every time.

A mate with a VL, same issue, replaced the battery; started first time, every time.

The car never showed any other signs of a dying battery, and it would load test fine. I don't have an explanation; and at the time frustrated the shit out of me. I went through wiring connectors, temp & CAS sensors, coils, leads, dizzy caps & rotor buttons, spark plugs; everything. No change.

I never looked at the battery because I thought it was fine.

How old is your battery? If it's more than 2-3 years old; it might be worth trying a known new battery, if you can beg/borrow/steal one for a few days.

Do you turn the key on then wait for the pump to prime, then wait a few seconds for the AAC valve to do it's thing?

I may be well wide of the mark, but in the absence of other solutions, and given it was an existing issue before your mods, it might be worth a try.

Edited October 18, 2011 by Daleo