Startup RPMs high when cold outside

[homeslicej2]

Now that it's starting to get colder outside, when I first start the car (mostly stock Redtop w/stock turbo/cams/etc.), it idles up to ~2200 RPM & stays there for about 30 secs before dropping down to ~1800 RPM & then it'll slowly drop idle RPMs as the motor warms up. The motor only does this when it gets around 50 degrees or colder outside. Any other time (summer for instance), it'll rev up to ~1500 RPM at startup & then work it's way down to ~900 RPM idle after a few minutes. I wanted to know if anyone else has this going on with their SR. Mine has been like this since the swap ~ 5yrs ago. I don't know if it is related to the removal of the air injection stuff from the exhaust & other stock items that most of don't swap over, or if it's maybe my IACV going bad, or what. I just don't like that it revs that high when it's cold bc of the wear on the motor that it must be causing. Any thoughts on the cause?

[PyR0NiAk]

I've seen several cars that do it... I wouldn't imagine it's doing any damage... The 1500 thing is completely normal. It's called "fast-idle". It's a warm-up period. Gets the oil flowing to the head more quickly and things of that nature.

[USMCgetsome]

it probably about that time to clean the iacv. You mentioned 5 years so i'd say clean it as a precautionary measure. I though it was to only get up to 1200rpm for fast idle

[homeslicej2]

I know about a fast idle for warm-up (I see that I didn't make that clear) I just thought that it was odd that it revs so much higher as it gets cold, and wondered if it was related to electronics going out or if it's just natural for the SR to rev that high when it is cold outside. I don't know about the S13 SR's but in the S14 SR FSM, there is an actual Fast Idle Cam (FIC some wax it seems) located in the throttle body that apparently reacts to the coolant temp coming in at the throttle body to modulate RPMs. I have ordered (it's actually backordered) a new IACV bc I'm replacing all the gaskets and hoses on the intake with my coolant flush and system maintenance this year. Thanks guys.

[amolao]

Mine does the exact thing, I took the IACV apart and cleaned it real good. No changes. I might also end up getting a new one. Somehow the cold weather (thru the MAF) creates that much of a confusion and loads a "weak" IACV high in RPM's...
And is not even that cold in AL, yet....

[homeslicej2]

Seems many vendors are having a hard time getting IACVs for the SR20det (RWD). Mine is backorder from Japan and the vendor (a nissan dealership) is telling me that they may not be available anymore. A different vendor gave me the same info. I don't know if any other SR20 model has the same valve, but I hope so.

[amolao]

where and you getting yours and how much, if you don't mind....?

[homeslicej2]

Pm'd you

[Hijacker]

Pretty sure s14 srs are different. I ordered an S13 for around $150 from frsport when i was doing my motor rebuild. The price has jumped considerably though. I thought i saw west covina or courtesy carrying them for a decent price

Btw. I don't think it can get cold in alabama. That place was only 10 feet from the sun last time i was there

[homeslicej2]

S14SR IACV is different, I just meant any SR20 from any platform, but apparently, there are none that match. FRsport now charges $420 for the S13 version. It seems no one has one in stock at a decent price though, I tried West Covina, Nissanparts.cc, and Courtesy. I've e-mailed some of our regular vendors too, but haven't heard back yet, I assume bc of SEMA.

[Hijacker]

http://www.enjukuracing.com/idle-contro ... -6974.html

http://www.phase2motortrend.com/sraacva.html

http://www.optionimports.com/itemdesc.a ... 15&eq=&Tp=

There's a few I pulled down off of my links of vendors. You said you tried some of our regular vendors, which I know those three are, but I figured I'd toss them up JIC you missed them.

[homeslicej2]

Thanks Bart. I've actually emailed all of the above. Yet to hear back. Jeff from 240sxmotoring e-mailed me today that he is sold out and no ETA on new ones.

[amolao]

Just a quick update on mine;
I decided to go ahead and check my Fast idle adjustment even though I adjusted this previously by FSM standards. Well, it was off. Not sure what might it caused it. I went ahead and readjusted back to OEM standards and the warm idle is now at 1500 rpm's, which is much better. And it gives me a little peace of mind during cold morning start ups.