Hard to cold start SR20 and idle bounces

[Didderson]

Hey guys I've been searching for days and trying things out here and there, but I can't get the problems in the title fixed. My car is quite tough to start when it's cold out. It runs at around 1500 rpm idle. I have no vaccume leaks, i used to at the bov, but that's fixed and it's still doing this: when I'm out of gears it will idle smooth BUT it'll dip from 1800 rpm to maybe 1200 rpm. Like slowly climbing toward 1800 and than, bwaaaaah, boggs to 1200, and climbs again.

I just found out today thru more searches that my oil weight is a bit off (I'm running 5W30 but it's winter here) I'll be changing that asap. I don't know what else could be my problem other than the IACV. I unplugged the iacv one time when it was jumping idle and it didn't change a thing.

Any thoughts? please help! I'm about to buy a new IACV if I can't figure this out!Thank you in advance.

also, the car doesn't like to run at low RPM's. sometimes i'll get it started but it'll be bubbling idleing at 8 or 900 and thankfully climbs back to where it's comfortable within 30 seconds.I set my timing DEAD ON 16 btdc but, I only set that timing at somewhere around 15 to 1800 rpm becaues my car won't idle. Would that affect my timing? i'm assuming no.

[Didderson]

alright well, my ECU throws me a 55 code which means everything's ok.

But it's still hard to start when it's cold. I used the pcv valve off of a sentra SER if that helps. maybe it's causeing a vac leak?

[Didderson]

Well all seems to be well. I guess the problem was my oil weight.I ran 5w30 for startup.Switched to 10w30 synpower today and it idles at 1200 no dipping or revving

The IACV screw is in all the way. I hear most people have to do this so I'm not worried.

[idahotuner]

glad you figured it out man. so what weight were you running. when i go to start up my car i am going to start it up let it run for 30 mins or so, then rev it up a bunch to redline, then let it idle, turn it off and change the oil. so do you think the weight of the oil i use will make a difference for that short of time.

[Hijacker]

Don't rev your fresh motor to redline unless you want to seriously hurt it. Fire it up, let it idle for a while and then once it's warmed up, take it out for a nice easy drive.

My mechanic mentor listed out a great way to help get a fresh motor to seat its rings as well. Find a good stretch of road where you can get up to 40 and leaving it in 4th gear, use 1/2 throttle to 3/4 throttle and get it up to 60-ish. Then back off the gas and let it coast back down to 40 and repeat that procedure about 10 more times. Varrying the load like that will help the piston rings seat in.

After that, drive the car casually for the break in period. You don't need to baby it, but don't go tearing up town either.

[idahotuner]

i am not breaking in the bottem end because i didnt do anything to it. moslty just breaking in the head. it has new cams and springs and valve seals. and plus the motor has been sitting with out oil in it while i fixed the oil pan. so basically it is more of a break in like after a car has set all winter.

oh one quick question on turbo lines. the oil feed came with two washers to use with the stock bolt that goes to the block. did one go on the outside and one on the inside because i dont want the holes to be off and my turbo to not get any oil.

[Didderson]

They're probably just copper washers that need to be used on both the inside and outside of banjo fittings so that liquid doesn't leak out.

The cold start problem lies in me not pumping the pedal before I try to start her. I guess I'm running a bit lean on startup. Still bounces a bit but I'll live with it until the local shop gets their dyno so they can ROM tune and what have you. Maybe I'll put a blacktop iacv in there w/ a metal screw.