Bad idle?

[ed1380]

I just rebuilt my 420a engine. (yesterday)
It started up, but I had to stay on the gas for a min before it would run by itself.

Now it runs ok at 950+, but if it goes lower it stutters. (yesterday was much worse, and turning on the A/C seamed to help).

900 seams high for an idle, but I've searched the forum, and it looks close to what others are getting.

So what's the normal idle? I'd just like to be sure.

What could be causing the stuttering?

THANKS

 

[xxraptor660xx]

Anywhere between 750-1000 is average. 900 is fine.

 

[ed1380]

Any idea why it's stuttering under 900 rpm?

 

[Shadow98]

TPS sensor or IAC (idle air control valve)

 

[fourreGsixty3]

Sounds like a FAIV problem. Are your coolant lines going to the TB? If not you will want to block the FAIV off because the wax pellet will not melt. Also check the TB in particular for any leak's...the TB shaft's are a good spot for leaking air.

Dustin

 

[ed1380]

Tb? Faiv?
turbo? forced air induction valve?


EDIT: finaly got throttle body. still don't have the second one

EDIT 1.5: found out what FIAV is

EDIT2: no coolant lines coming to TB. maybe that's only on the 1 g's

EDIT3: found this (pic)

 

[ed1380]

So am I fixed now?
http://www.youtube.com/watch?v=YTdI7qtTOyM

 

[fourreGsixty3]

Looks good to me. What did you wind up doing to it?

 

[ed1380]

This is after a few minutes, so it was already warm. When cold it worked worse.

new spark plugs.

 

[ed1380]

While i'm changing the fuel filter I decided to take the TB off, and cleaned around hoping itll solve the idle surge.
main reason I'm posting this is, cause while searching i found a few links about this problem, but they're about the 1G. and I'm looking for 2g articles.
thanks

 

[ed1380]

i finally got a chance to look at it today. i tested the tps w/ an ohmeter and it seems to be working. i checked the o2 sensor and thats good too. tried 2 other sensors and it still got the rough idle.
i got a video of it. you can see that when running richer it runs nice, but then the stupid ecu leans it out.
YouTube - dsm idle

what do the experts think it can be?