Rough idle Nubira

NubiraDellwoo · Post by **NubiraDellwoo** » Tue Dec 12, 2006 6:58 am

Edited... update...
So I finally figured it out... It is the motor mounts that are causing the vibration... I used a floor jack and lifted the engine slightly under the oil pan and there it was... vibration gone... wow... Now to change them...

OK... I'm new to the world of the woo and this forum... so go easy on me... Please

I have a '01 Nubira SE 2.0 16V manual trans... that I just purchased... used
I've had to do a few things to it including... Fixing the oil leak at the valve cover and replace the bushings of the CA's... So far so good... I'm learning... Picked up an FSM so that helps a bit...

The problem is that the idle is real rough... But drives fine otherwise... The idle control seems fine and kicks down properly after warm up... But that is when the vibes began... Coates Daewoo where I've ordered some parts advised me that it may be the EGR... He suggested that I do a temporary block off and see if it still idles rough... It does... I've replaced plugs and the wires seem fine... though they did get some oil on them when the valve cover gasket was leaking (cleaned them up though)... There is no misfire and it runs great at anything above idle...

Now here's a problem that I found and might be related... The hose going from the top of the valve cover to the intake tube was cracked when I purchased the car... I replaced it with something I modified from my local auto parts store... That works fine BTW... But I can see that a lot of crap was sucked into the TB and probably everwhere else in the intake system... Could it be that the injectors are gunked up ? But wouldn't that cause it to run crappy in all facets other then just at idle ? Should I break down and have an intake/injector flush done or is it possibly something else that is causing the issue ? And is there anything I should watch out for as far as a local service garage doing that flush ? (other then them charging me $ 100's

)... Oh there is no CEL

Lastly I read a heck of a lot of the past threads and didn't see one related... though I may have missed it or it was written under a title that I wouldn't have known to read... I hate being a noob

...

Thanks for any insight you can give...

Daniel · Post by **Daniel** » Tue Dec 12, 2006 7:27 am

Hi,

You'll find the service manual in General Info Section/ General Off-Topic. Then in "Engine Controls" there is a section about Rough Idle.
In the How-To section of this forum is a topic about cleaning crap in TB. Not yet done it myself.
Also look at Idle Learn Procedure.
Hope it helps.

Daniel

NubiraDellwoo · Post by **NubiraDellwoo** » Tue Dec 12, 2006 7:36 am

Daniel wrote:Hi,

You'll find the service manual in General Info Section/ General Off-Topic. Then in "Engine Controls" there is a section about Rough Idle.
In the How-To section of this forum is a topic about cleaning crap in TB. Not yet done it myself.
Also look at Idle Learn Procedure.
Hope it helps.

Daniel

Thanks... I'll look for that... I'm trying to feel out this forum... and it's format...
I'm used to different forum formats and this one has me a little confused... But I'll get the hang of it...

Edited... OK I only found a download for the Lanos or whatever... Not sure if that is what I need... Oh and I have the Nubira service manual... I was just looking for a thread or sticky that referred to this issue... Oh well... I guess I better read my FSM again...

MMamdouh · Post by **MMamdouh** » Tue Dec 12, 2006 3:14 pm

most probably your TB is fully loaded with dirt so you need to take off the TB abd IAC for a real good cleanup then put every thing back on, this will end up your idling problems.

MMamdouh

NubiraDellwoo · Post by **NubiraDellwoo** » Wed Dec 13, 2006 9:59 pm

MMamdouh wrote:most probably your TB is fully loaded with dirt so you need to take off the TB abd IAC for a real good cleanup then put every thing back on, this will end up your idling problems.

MMamdouh

Thanks for a reply...

I had the vehicle serviced for throttle body/intake/injector flush (Wynn's)... (injector cleaner was added to the fuel tank/Maybe more time needed to flush the injectors thoroughly ? )

I personally removed and cleaned the IAC (which was very dirty)...
Cleaned the IAT

Installed:
New plugs @ .044
New air filter
New fuel filter
Cleaned an reinstalled the Battery cables (to also reset PCM)
Pulled/cleaned the EGR (and ran a block off test)
Replaced PCV hose as it was cracked... As well as the small one going to the TB (vaccum ?)... The big one was cracked in half (for how long I don't know/previous owner) and the little one was very soft and mushy...(There is no valve on this model ? The FSM refers to the PCV but no valve ?)

So far the car runs great everywhere... But the idle... It's still extremely rough... especailly if it is fully warmed up...

The IAC seems to kick down properly after warm up... But when it does... that's when the rough idle begans...

I don't have the diagnostic tools to test values on EGR, IAT, IAC, MAP, O2 and so forth...

I have not looked at the TP as far a cleaning... should I ?

Should I just start replacing all these sensors one at a time until the culprit it found ?.. And if so in what order ?.. (That'll be costly I'm sure

)

Well... as for a good car otherwise... I'm really frustrated... (Wish I could find a service center that was trustworthy and willing to dianose this issue)... Need to do a timing belt change... But if I can't get to the bottom of this idle issue... Then I won't be enjoying driving this anyhow and will just let it go to the junk yard after it eats the valves... LOL

Again... there has been no CEL codes... Except initially after the TB/Intake/Injector flush...

What should be my next step ?

Thanks ahead for any advice that can be offered...

MMamdouh · Post by **MMamdouh** » Wed Dec 13, 2006 10:06 pm

TPS is not cleanable or servicable, if it is bad you will idle at too high RPM or the RPM will jump back and forth from 1500 to 2500 or so

do you see black smoak from the exhaust when the car is fully warmed up? if so then the O2 sensor is not functioning properly.

do you have trouble starting the car? does it sputter at the initial startup then start to behave well? is that sputter asociated with some black smoak?

if all answers are yes then you got leaky/dirty injectors so you better clean them using an ultra sonic injector cleaning machine or buy new ones.

replacing sensors one by one is an extreamly expensive way to do it... try to borrow sensors from a friend or so to test and pinpoint the bad sensor if any.

MMamdouh

NubiraDellwoo · Post by **NubiraDellwoo** » Thu Dec 14, 2006 2:01 am

MMamdouh wrote:TPS is not cleanable or servicable, if it is bad you will idle at too high RPM or the RPM will jump back and forth from 1500 to 2500 or so

K... Not doing that...

do you see black smoak from the exhaust when the car is fully warmed up? if so then the O2 sensor is not functioning properly.

No black smoke or blue or white... Plugs look good as well

do you have trouble starting the car? does it sputter at the initial startup then start to behave well? is that sputter asociated with some black smoak?

Fires right up... No stalls... does not run on either

if all answers are yes then you got leaky/dirty injectors so you better clean them using an ultra sonic injector cleaning machine or buy new ones.

I'd say the answers are all no to this...

replacing sensors one by one is an extreamly expensive way to do it... try to borrow sensors from a friend or so to test and pinpoint the bad sensor if any.

I have no friends that have this sorta car... They all have Toyota 4X trucks... as I do (offroad fun )... And yes they laugh at me... (all in fun though)... LOL

Looks like I may have to bite the bullet...

MMamdouh

It would seem that I'll just have to start ordering sensors and try one at a time until the culprit rears it's ugly head... Would you have a good idea at which ones to try first (order) ? Say like the EGR or what ever might most likely be suspect... I was told by Gary over at Coates Automotive (Daewoo parts supplier) that the EGR is most likely suspect of all the others...

Thanks again for taking the time with me...

ubuyau · Post by **ubuyau** » Thu Dec 14, 2006 7:54 am

You've done the full service so its unlikely to be a filter.

I'd take it to a shop and atleast get the ecu scanned for any fault codes - see if a sensor has gone dodgy. Should only cost a few $ to have them scan it for you.

How about resetting the ECU yourself?

--Tim

GsiTurbo · Post by **GsiTurbo** » Thu Dec 14, 2006 3:03 pm

On the driver side of the motor, by the coil packs, there are 2 sensors (both for coolant temperature). One of them is connected, one not. Once the motor is warmed up, and idling rough, disconnect the sensor. If there is no change, this could be your CTS (coolant temp sensor).

Also, the 2.0 motor are sort of notorious for building crap in the intake which may affect idle. I'd put oil catch tank on the breather tube going from the valve cover to the intake. Hope this helps.

NubiraDellwoo · Post by **NubiraDellwoo** » Thu Dec 14, 2006 4:13 pm

ubuyau wrote:You've done the full service so its unlikely to be a filter.

I'd take it to a shop and atleast get the ecu scanned for any fault codes - see if a sensor has gone dodgy. Should only cost a few $ to have them scan it for you.

How about resetting the ECU yourself?

--Tim

Yeah I guess it can't hurt to have it scanned. But without a CEL would anything show up?
As far as the reset... thought I did it... At least I followed the methods outlined in the "How to Section" Unless there's something else I'm missing...

GsiTurbo wrote:On the driver side of the motor, by the coil packs, there are 2 sensors (both for coolant temperature). One of them is connected, one not. Once the motor is warmed up, and idling rough, disconnect the sensor. If there is no change, this could be your CTS (coolant temp sensor).

Also, the 2.0 motor are sort of notorious for building crap in the intake which may affect idle. I'd put oil catch tank on the breather tube going from the valve cover to the intake. Hope this helps.

Thanks I'll try that today and hope that is the problem... that would be great if it is...
Even though I paid for the cleaning service... I'm going to pull the TB again and clean it some more... Maybe the service guys were not thorough... Wouldn't be the first time shoddy work occured... LOL

Oh and on that oil catch tank on the PCV hose... what did you use ? Got a pic ? What about that little one that goes to the TB (What's this one for ?)... Mine was real gummy... It would seem that alot of oil/junk tends to pass thru these two hoses and eats them up...

Thanks folks... it would be great if I get to the bottom of this issue so that I could post on this thread that the issue is fixed and what it was...

NubiraDellwoo · Post by **NubiraDellwoo** » Fri Dec 15, 2006 2:16 am

GsiTurbo wrote:On the driver side of the motor, by the coil packs, there are 2 sensors (both for coolant temperature). One of them is connected, one not. Once the motor is warmed up, and idling rough, disconnect the sensor. If there is no change, this could be your CTS (coolant temp sensor).

Ok there are two connectors in that location... One is a plug style connector to a sensor (located further rearward)... and the other looks to have a spade style connection (located forward of the plug in connector)...
You referring to these ?

When I unplug the rear most plug... it hesitates or studders momentarily... then fan automatically kicks on and stays on...
When I unplug the forward spade type plug... The temp gauge goes dead...

Neither affects the idle though... and so I'm assuming they're working correctly

The CEL does light when I disconnect these... So I know the CEL is working

GsiTurbo · Post by **GsiTurbo** » Fri Dec 15, 2006 4:31 am

Ok, well at least you know now the CTS is working properly. I thought that possibly its reading real warm, hence less fuel and causing hesitation at idle.