rough idle at start up with no CEL

**willowtreexx** · 07-07-2008 09:07 AM

So to start off i did search and most people had a bunch of aftermarket stuff on and CEL.

I will start up my car and i have a bit of a rough idle. It likes to sit around 1.2rpm and then every now and then just drop to 700rpms. I replaced all the vacuum lines. the TB and MAF. i dont have a CEL either. So im kinda puzzled. I do have a boost guage that i just installed this weekend, but this problem started way before that. i installed it to see what type of boost my car was producing to try and see if i have other problems. when idleing i have boost of about -10 and then when the car idles rough it fluxes between 0 and -20.

from what i could gather on my searches people talk about the SAI and coolant temp sensor... could those be my culprits?

TIA

**fikes** · 07-07-2008 09:18 AM

When you installed the TB and MAF did you do a throttle body alignment with a vag tool or vag-com? Seems thats all it sounds to me. Mine was the same way only it only happened when I reved the engine.

**willowtreexx** · 07-07-2008 09:24 AM

whoops sorry, i didnt get a new TB i just cleaned it...my bad

**njm23** · 07-07-2008 09:34 AM

well when idling it isnt boost, measures in Hg, and it should be right around 20-21 when idling with no a/c or anything.. The SAI pump puts the car right around 1100-1200 rpm's when it is started cold then it drops down to right about 800 when it turns off fyi. What is your boost while driving? should hit right around 8, unless your chipped but i dont think you are..

**fikes** · 07-07-2008 09:34 AM

Well usually if you unplug it you still need to do a Tb alignment. That would be my first plan of attack.

**willowtreexx** · 07-07-2008 09:41 AM

well to be honest its been a work in progress and i havent been able to drive it besides one mile. I havent had headlights, bumper, plates. I bought it in a non running condition and have been putting it back together. Maybe i dont have an issue then if its just the SAI kicking on and off. I have my fender, bumper and C/o's being shipped today. I also got my headlights on so i might try and drive it a bit today and let you guys know.

**willowtreexx** · 07-07-2008 01:10 PM

I was able to drive it around today and everything seems to be just fine. only have around 7-8 psi laaaaaame haha but i know i cant expect anything from a K03 all stock

**Rau** · 07-07-2008 01:58 PM

Originally Posted by njm23

well when idling it isnt boost, measures in Hg, and it should be right around 20-21 when idling with no a/c or anything.. The SAI pump puts the car right around 1100-1200 rpm's when it is started cold then it drops down to right about 800 when it turns off fyi. What is your boost while driving? should hit right around 8, unless your chipped but i dont think you are..

not to hijack a thread or anything, but i too put in a boost gauge to find out what kinda boost i was pushing, and with only exhaust its around 10-11 psi. am i boosting too high or something? (stock K03, 111,00o miles )

**Nebone** · 07-07-2008 02:10 PM

Thats OK for the 2001 model.

willowtreexx - you must have a vacuum leak since your vacuum at idle is so low.

**fikes** · 07-07-2008 02:13 PM

Originally Posted by Rau

not to hijack a thread or anything, but i too put in a boost gauge to find out what kinda boost i was pushing, and with only exhaust its around 10-11 psi. am i boosting too high or something? (stock K03, 111,00o miles )

You have a 2001 with a k03sport which has a stronger shaft so they made it boost a little more giving it the 170hp stock rather than the 150 most of us have.

**willowtreexx** · 07-07-2008 04:23 PM

i got a vacuume leak? shoot when i was driving it around today i was at 20Hg just sitting at idle and when i would floor it i would see about 7-8psi. i think i just needed to let the car warm up. it hasnt run in over two years so this was its first time. and i have a 122,000 miles on it

**njm23** · 07-07-2008 04:26 PM

^^yeah, your good. No leaks or anything. Car is right about where it should be

**fikes** · 07-07-2008 04:55 PM

Originally Posted by njm23

^^yeah, your good. No leaks or anything. Car is right about where it should be

What does that mean. he just said in the first post he has idle problems. Although you may not having a leak I would check the hoses out. I had a similar problem where the rmps would jump around when I revved it even though I did a TB alignment. Problem was 2 of the hoses were collapsed causing weird idle and boost problems.

**willowtreexx** · 07-07-2008 05:18 PM

it doesnt jump around like a kangaroo on crack, it starts out at like 1200rpms and then slowly goes down to about 800rpms and sits there. Im used to the honda accord that ive been driving while i put this back together that once you start a car the rpms are just solid, this was the first car that starts out high and then settles a bit lower. I got the info that it was the SAI kicking on and off that will make my RPMS move a bit.

thanks njm23 with this and the dp haha :)