Cold start 3rd gen 3sgte issue, RPM and A/F bouncing on cold starts (vids) Options

[mgnt232]

Hey so just now starting to get cold here (30-40 degrees F during morning starts). and my car is going nuts lol. its only on cold starts too, so maybe there is a fix, or someones had the problem.
Anyhow i have vids of whats happening on the cold start, and then like 3 mins later when it warms up just a tad and its fine.
Only at idle as well, if i gas it even a little bit it just holds around 2k and doesn't jump. Maybe i can just tighten up the throttle cable a little for the winter months?
It's fine when warm and driving too, no differences i can notice

Cold start up vid



Warmed up (fine)





This post has been edited by mgnt232: Nov 13, 2013 - 5:48 PM

[lagos]

check your coolant temp sensor?

[mgnt232]

cough* where is that and how do i 'check' it?
The second i push on the gas, just enough to put the rips not even +100 where it is on the cold start its fine. Only at idle. Ill get a chance this weekend to look at everything

[Sunny]

Hi,

your engine is not warmed up fine, how high is the rpm once the temp. needle is in the middle of the scale? or after a drive of 10-15km?

-> if it is around 1000rpm everything is fine......

you just have a little temp on the water but your oil is still cold



greedz

This post has been edited by Sunny: Nov 14, 2013 - 4:45 PM

[mgnt232]

no no confusion here sorry for that.
the second vid was just like 5 mins after the start up where the rpm's dropped slightly and it stopped going crazy.
After its actually warm (operating temp) the oil pressure is around 30psi at idle and RPM around 800-900 at idle.

This post has been edited by mgnt232: Nov 14, 2013 - 5:07 PM

[mgnt232]

bump?

[malecrod]

Also Check the throttle cable and make sure its not getting stuck or keeping the throttle opened somehow. Also check your TSP connector to make sure its not disconnected. Hope this helps.

[mgnt232]

the throttle cable isn't stuck. I took a look over everything today.
tightened the cable just a tad too. it was like 80 here all day so it wasn't acting up at all. Still curious one what it is

[presure2]

looks to me like a large vac leak. the RPMS are really high in that 2nd vid for a warm idle.

check all the plugs attached around the throttle body (TPS,IAC,MAT)
you can also try unpluging the IAC while the engine is in cold start mode, see if anything changes.

again, that cold start vid reallllly looks and sounds like a massive vac leak, or somthing wrong with the IAC.

[Hafkai]

The bouncing idle seems to be caused by the deceleration fuel cut off, with the engine warmed up it cuts fuel till ~1100rpm i think, on a cold start this point could be at ~2000rpm. A vac leak could be enough to raise the idle over this point and it will start to bounce as long as you don´t give it some throttle.

[mgnt232]

The second again video was only after 2 or 3 mins of running, not operating temp. At operating temperature the RPM's are around 800-900.

Ill unplug the IAC next time its cold see if anything changes, its been like 60-70 all week. If it changes anything should I clean it or just replace?

Ive over looked the vacuum lines before when I wasn't hitting boost (but that was just the code 54). Ill look over them again, but its kinda hard to find them all lol.