gp1817

im boosted and fully tuned on a aem fic.....recently,on hot start ups....my idle will become lil bouncy for like a good min or two but never stalls....while this hapens,the afrs,go from 14.5 to really lean and back and fourth,after a min or two the idle reajust and everything goes back to normal as well as the afrs......recently the weather over here on the North east,been warm to ice cold and so fourth,but im thinking its something else,like maybe a dirty maf sensor,or maybe a vacuum leak,its really been too cold to check over the car,but any input would be great

criminaltc

And your tune was for sure good prior to this? Otherwise, I've had this happen to my 700hp monster and it was the altenator.

gp1817

never did it prior to my tune....the alternator can cause weird idle issues !!!!

criminaltc

Ah, so this is happening right after a tune? Well no doubt its the tune brother. And yes, alternator can cause this sort of idle if the car keeps wanting to die. It'll lower and then bounce back up, hold, lower, bouce back up, hold... yada yada.

gp1817

no not after the tune...i say about 4-5 months afterwards...starting to experience weird idle issues on hot start up...from 1st gear into neutral....the idle would boucne a lil bit to a point where the car would just die,but after a few min of driving it would be fine.....but now...on hot startups..idle bounces up and down from like 1100 rpm to like 500 rpm back and fourth give ir take...tryes to settles down after a few secs but continues for like a good min or two..but returns to normal.........ask a few of my buddies..they said the alternator would cause such a issue....if it wasnt happening directly after the tune..i noticed when i have my head lights on,i get kind of harsh idle issues coming to a stop from like neutral....which wasnt to harsh when lights were off,which lead me to beleive to be a eletrical issue

gp1817

forgot to mention i saw the volts on my scangauge and its 13.8-14.1..it doesnt dip lower then the 13's

criminaltc

Autozone can test your alternator.

gp1817

so i re-examined my alternator.....at idle its doing 13.1-13.3..when my fans kick in,the lowest ive seen it drop was 12's.....whats your personally opion,does it sound strong or kinda weak

criminaltc

Eh. I've seen worse. I was hoping you'd say mid 11's because then I could tell you for sure, but 12's aren't telling me too much, that's not too bad. I guess, what is your battery sitting at? Dead batteries can do this as well, but usually not like you described, but at least it's a shot.

gp1817

i have a optimum red top..lil over 3 yrs old....i mean i know the optimal volts are 13.6-14.....but i dont have a new batt...so not expecting that...but my battery may be getting weak....when my fans kick on...the lowest i seen is 12 volts...give or take...my idle is 13.1-13.3.....right around there...driving pretty much at that point...doesnt lower....i guess if my alternator was going it wouldnt properly charge my battery.....

criminaltc

Correct. A bad alternator can can effect a battery. Not to mention, optimum is complete junk.

gp1817

hmmmm.......whats a decent battery other then stock.....whats wrong with optimum that makes it junk !!!!!

criminaltc

I just always see them dead and people having problems. Anytime people are having problems early on a batteries life, you open the hood and there's a red top or a yellow top!

gp1817

interesting...your prob right..my first red top.....ive herd mixed reviews on these batteries,some say there life is short others say,there long,so should i get a stock battery or is there anything out there,thats better then stock esp on cold starts....

criminaltc

I'd say our stock battery, mine was panasonic, is great. Super reliable and all that jazz. A bit pricey, but at least you know you are getting exactly what is made for the car you know.

paul_dezod

Cams by chance?

gp1817

nope,motors all stock.....if i let my fuel pump prime for like 5 secs before starting..it does it,if i prime the pump for alot longer,its not as harsh...

2T0neTC

It's the heat. I have the same issue. I drove it all during winter and it never died once. it starts warming up come spring time it dies like crazy. Just change your exhaust manifold to something like this and heat wrap the crap out of it. Also get a cut out hood like evo 8/9's do.