Cold Start

[08r3308]

Have a bit of issue with my cold start.

It starts low revs turns off , next start fires up fine.

This only happen when its cold, i cleaned aac valve and check for air leaks.

If i disconnect aac all together , brown and purple plug makes no diff to start.

Any ideas , could aac valve be gone?

[Kenna802]

i had same problem, make sure your water line going to the throttle body is bleed properly as if its not it cannot sense the cold water and activate the cold start.

[08r3308]

Where is the bleed valve? Pic would be great. So i can try that

[SargeRX8]

You'll see it ontop of in the intake side of the plenum towards the front. It has a yellow warning stick saying NEVER OPEN WHEN HOT. I don't think that will have any effect. My old car done EXACTLY the same thing, cold morning starts it would crank start then die after a couple of seconds unless I blip the throttle. The problem went away as soon as I fitted my power fc. I never found out what the problem was though.

Its not likely to be the AAC valve faulty as with a Power FC this issue is non existant.

[08r3308]

Thanx , it is weird car warm and starts fine idle fine. I changed spark olugs, coils are new, fuel filter,checked afm,new collant sensor but i did not try bleeding coolant , will see how i go . I hope it fixes it

[koduRB25det]

mate, just check your fuel pressure regulator. disconnect tiny vac hose connect to the plenum and start the car. see any change. if it starts fine it's your fuel pressure regulator. what happen was your cold morning enrichment was very lean. then change your pressure regulator.

make sure to put it back tiny vac hose b4 you driving. let me know how u go.

Thanx , it is weird car warm and starts fine idle fine. I changed spark olugs, coils are new, fuel filter,checked afm,new collant sensor but i did not try bleeding coolant , will see how i go . I hope it fixes it

[08r3308]

Tried fpr and same thing, also bleed coolant and also no help. Im stumped to what it is.

Anymore suggestions?

[koduRB25det]

i'm having this problem nearly 1 year[r33 s2]. not solve yet. what i found was i'm loosing fuel pressure when car stops for a wile. after 10-15 hrs car stops pressure completely loose in injector rail. i checked with pressure gauge. i'm waiting for my new fpr.

if u can try to clean your injectors.[remove and take it to inj cleaning place.] if u are in sydney let me know i will do it 4 u free.

Tried fpr and same thing, also bleed coolant and also no help. Im stumped to what it is.

Anymore suggestions?

[08r3308]

Could it be fuel pump? Are you mech or just know someone that does fuel injector cleaning. Yes im in sydney

[koduRB25det]

yes i am a mechanic. it cant be fuel pump. i already change the pump. but no luck.

this cold start issued caused lot of things.

chk ur earth points,batt voltage, spark plug heat range+gap , vac leaks etc.

if above all ok chk ur fuel pressure with pressure gauge. see what happen to ur pressure in cold mornings or after long stay start.

pm ur no will call u.

Could it be fuel pump? Are you mech or just know someone that does fuel injector cleaning. Yes im in sydney

[central coast person]

Its your injectors, they are leaking when it gets cold. If you want to check this, prime the fuel pump 5 times before you crank the car (when its a cold start, if its warm the fuel will just vaporize). Your car will start up and run rougher than usual and stall faster.

You can also check this by pulling your injector rail out and pull the electrical plugs on them and prime the pump and you will see them drip fuel.

[08r3308]

Did this happen to your car too?

So actuall injectors not orings

[koduRB25det]

agree with "CENTRAL COST PERSON". when ur inj are blocked it happen. clean ur inj with ultrasound cleaning 90% they fix the problem.make sure to replace all o'rings on inj.

[08r3308]

But if they leaking do they leak at injectors? Or orings? If injectors wouldnt it mean i need new injectors

[central coast person]

The fuel we have in australia has probably wrecked the injectors. You can get them cleaned but its about $200 and you run the risk of it doing nothing as they could be damaged. A set from JECS which are the genuine nissan ones cost less when you buy them from USA online than Nissan selling them to you. Its less then $600 too your door for the 'Genuine ones', or maybe its time to upgrade them.

Yes this has happened to my car, i just know that its injectors because if it were a sensor the problem would be intermitant where as our was just on start up and the fuel was vapourised on the first few cranks leaving the 2nd start up to not run a lumpy rich start.

*NOTE if you have seen car run a RICH map they run the same but constantly so that how i knew it was fuel related

[SargeRX8]

The fuel we have in australia has probably wrecked the injectors. You can get them cleaned but its about $200 and you run the risk of it doing nothing as they could be damaged. A set from JECS which are the genuine nissan ones cost less when you buy them from USA online than Nissan selling them to you. Its less then $600 too your door for the 'Genuine ones', or maybe its time to upgrade them.

Yes this has happened to my car, i just know that its injectors because if it were a sensor the problem would be intermitant where as our was just on start up and the fuel was vapourised on the first few cranks leaving the 2nd start up to not run a lumpy rich start.

*NOTE if you have seen car run a RICH map they run the same but constantly so that how i knew it was fuel related

My car had the same issue as him, why did the problem completely go away when I fitted a power FC?

[08r3308]

Hmm not sure . Is aac valve allways adjusting idle? If i unplug it while car runs nothing changes

[SargeRX8]

Hmm not sure . Is aac valve allways adjusting idle? If i unplug it while car runs nothing changes

Turn your air conditioner on, that tells the AAC to let more air in to raise the idle and keep the car on. If nothing happens then, could be your AAC. But mind you, my car did do EXACTLY what you are saying here, it starts cold first time spluters and revs just die out. As soon as we fitted a power FC the problem is gone.

[08r3308]

Maybe i should try different ecu?

I tried aircon and it kicks in revs go up

[mad082]

there is also a cold start valve, which works independant to the IAC and AAC. it's also in a bitch of a place to get to.