Not boosting properly: need help

[all-Canadian11]

Ok i have had my skyline for a few months now, and i am having trouble both with the start up and boosting of my car when it is cold.

When i turn the key over the car starts but the rpms flutter low then it dies, this happens a couple of times unless i add some gas.

as for the boosting there are times it feels like i am getting no boost at all, and other times it boosts quite choppy (boost kicks in and out as im cruizing along).


If anyone could help that would be great

[kyles_r32]

if you have a vented blowoff valve with will be hard to start in cold start...i know mine is. And you shouldnt be boosting when the car isnt warmed up it runs richer in cold start and thats why it kicks when your boosting.

[Skym]

Atmosphere vented BOV being adjusted too soft could cause your problems and atmosphere vented BOV shouldn't be run with MAF. But I've found stock BOV gasket to be use once only type of gasket and never seals correctly after removing BOV and refitting BOV. If stock BOV flange gasket is used with aftermarket BOV flange, could cause problems.

Recirculated Synchronic BOV is better in my opinion due to using a O ring on flange and increases response of engine. Once you get past installing flange properly (really easy to do) and tightening screws properly, have 0 problems with it.

Boost + cold engine is not a good idea, as some have had engine failures that way (cold oil not lubing properly, etc). That's why I warm engine up before driving.

Another thing it can be for hard cold start is boot bulb draining battery a bit. Removing bulb can fix draining battery problem.

[DreadedFist]

as for the boosting there are times it feels like i am getting no boost at all, and other times it boosts quite choppy (boost kicks in and out as im cruizing along).


If anyone could help that would be great

This happens to me if i drive without letting the car warm up for five or six minutes. I believe it's jumping back and forth between normal maps and cold start maps. It's a very noticable jerking. Car is much louder when driving in the cold start maps, i guess because its running really rick plus the ignition timing is retarded?

The jerky cold driving became much more aparent as I added new parts. Downpipe and testpipe made it a bit more obvious, then the front mount, and now a 3.5" catback with no resonator. Seems like my breathing mods have made it run like **** in cold start, which is why i always let it warm up for at least 2 or 3 mins before driving it.

And please dont drive hard or go into boost when the engine is cold. You car actively hates you because of it.

[Skym]

Stock ECU protect's engine until coolant temp is up to roughly 30 degrees or so by pulling ignition timing, etc. Engine probably would feel flat when ECU does this.

[all-Canadian11]

No matter how long i let the car sit with the engine on, i still have the boosting problem.
As for start up, it never used to be a problem. it only started happening about a month ago and even then it was only happening ever so often. Now it is happening EVERY cold start.
one of the mechanics i went to did suggest that my BOV was releasing air when it shouldnt be. And another said it could be my MAF.

noone has been able to tell me that it is anything specifically, they have just guessed what it could be.

[overboostedlebaron]

When i turn the key over the car starts but the rpms flutter low then it dies"

my car did this for a month or so and it turned out that the fuel pump died.