Very Hard To Start Cold

[Flash89]

plugs are new (gaped 0.8), well im going to see if new coil packs will make a difference, car has been misfiring on full boost or about 3500 4000rpm

Edited July 4, 2010 by Flash89

[Flash89]

well new coilpacks fixed the misfiring prob. no difference with the cold start

yeah when i do the idle adjust. car is prob reving around 900rpm take the tps plug off the car raises idle tp about 1200-1300 when i screw in the idle screw the rpm dont change at all. even tho the screw is all the way in too.

[mad082]

try starting the car with the TPS unplugged and then adjusting the idle and see if that lets you adjust the idle.

[08yannch]

is interested in this thread, as i have similar problem

Q: would changing to a different oil help at all? 15-40 simi sin to 5-30 full sin

[pipster11]

in the oil thread everyone has pretty much agreed that 10w40 is good for rb25's

but a 5w40 would be better again being thinner when cold

pull the air regulator (under the throttle body) out and give it a clean, make sure it goes all the way closed too (there is an adjuster)

also pull the iac valve off (one with the idle screw on it, at the back of the plenum) and clean it

clean both of them with carby/throttle body cleaner

[Flash89]

yeah i will give them both a good clean today

[Flash89]

gave them both a clean, still the same, is there a way to check if the air reg and iac valve are working properly?

[Tristan21]

The spring in the AAC valve should move freely. Also check the voltage on the solenoid.

Not sure about the air regualtor, I have two of them and they both cause bad cold starts. I actually think the spring is stuffed as the small bi-metallic disc does not fully close. Anyone know if this disc is supposed to remain closed with no voltage?

This thread is great when diagosing similar problems. http://www.skylinesaustralia.com/forums/Fi...ob-t174735.html

[08yannch]

when ur car starts in the cold what rpm does it sit at and when it is hot what rpm does it sit at when start

it is easer to start when hot

what volts do u get with everything off and what it the voltage drop when u try to start and what type of battery do u have and how old is it

lets try to get this fixed.

[vitz_n1]

i used to have the same problem.

Try adjusting the mixture screw... i think thats what its called. Its the screw on the manifold, on the same unit as the aac valve but on the other side. Wind that out a few turns, then start her up. If you still have trouble, get the car to temp and check your timing. I did this and new plugs and it fixed her right up.

However, it took a few goes to get it right with that screw, it progressively got better and better as i screwed out so i just did it one turn at a time. 2.5 turns got her perfect for me.

Mine was fully screwed in at first and therefore letting no air in and flooding i think... sounds like the same for you.

[Flash89]

i think you are talking about the idle screw. and yes i do disconnect the tps when i try adjust the idle still, the rpm stays the same.

yes it fires up straight away onces its warm.

battery is like 3months old and its massive, 4x4 battery. dont ask why i just replaced the same battery that was in there before

what i would also like to do, what is the difference with cold and warm starts, like with cold starts does it give less air cause its cold which means the air would be denser??

[08yannch]

well i think we should rule out the battery ?

do u have a multimeter?

and or a

battery tester?

if battery tester test battery to see if u have enough CCA's

if multimeter then its a bit tricky. ideally you would use the battery tester but if thats not an option then make sure the battery is fully charged. attach multimeter u should read about 12.7V and wile reading the multimeter try and start the car if voltage drops bellow 10V it might be a good idea to take it to ur local auto 1 to have it tested there.

if the battery looks angry then replace and also check your alternator. all this is. is a multimeter attached to the car with it running and you should see between what 13.5V and 14.5V then turn on head lights. the voltage should drop for a second then come back up. also check for current draw. this is the multimeter attached in series to the battery with every thing hooked up but off, set multimeter to amp's setting.

next is your air filter clean? if not clean it

have u recently cleaned your AFM if not clean it.

oil change try something with a lighter weight at cold temp

setting the A/C to "cold" will help even if u leave the A/C off because this will make your coolant bypass the heater = faster warm up

[Tristan21]

Ok I now have this same problem.

Car will not turn over unless I pull out the coolant temp sensor. I assume the air regulator is stuffed?