Rough Idle at First Start-up - GM Forum - Buick, Cadillac, Chev, Olds, GMC & Pontiac chat


Bonneville GXP/ Northstar Powered Cars Discuss your Bonneville GXP and/or any other Northstar powered Olds or Cadillac... Including the 3.5L Twin Cam V6 (Short Star ) 4.0L and 4.6L Northstar V8's. Please use General Chat for non-mechanical issues, and Performance and Brainstorming for improvements.

Reply
 
 
 
Thread Tools Search this Thread
Old 01-05-2005, 05:38 PM   #1
Member
Posts like a V-Tak
Thread Starter
 
Join Date: Apr 2004
Location: St. Petersburg, Florida
Posts: 72
Thanks: 0
Thanked 0 Times in 0 Posts
obis88 is on a distinguished road
Default Rough Idle at First Start-up

Have any of you GXP owners noticed a fairly rough idle for about 30 seconds or so after you first start your car? Every time I start it I get this rough idle like it'* running on 6 or 7 cylinders and then it smooths out after about 30 seconds. Not really too worried but wondering what it might be or if others have noticed this. Any ideas?
obis88 is offline   Reply With Quote
Old 01-05-2005, 06:53 PM   #2
Member
Posts like a V-Tak
 
Join Date: Nov 2004
Location: Daytona
Posts: 73
Thanks: 0
Thanked 0 Times in 0 Posts
chuckwi11 is on a distinguished road
Default

Yea, mine idles in an "unusual" way for a moment of two when first started in the morning. Might be that it'* cold... or it could have something to do with the ignition system on N*... my understanding is that each pair of cylinders is set to the same coil and fires one ignition spark and one redundant spark... it may be that right after start there is unburnt fuel on the down stroke and maybe it'* detonating, after one or two cycles it clears out... I know I am not explaining this properly, maybe one of the resident gearheads can do a better job???
chuckwi11 is offline   Reply With Quote
Old 01-09-2005, 12:00 AM   #3
Junior Member
Posts like a Ricer Type-R
 
Join Date: Nov 2004
Location: Los Angeles
Posts: 19
Thanks: 0
Thanked 0 Times in 0 Posts
coyote is on a distinguished road
Default

Yes, I get the same behaviour, exactly as you describe. However, I'm afraid to bring in in for service (see my post - "GXP Maintenence - where?"

I'm tempted to hook up my OBD-II scanner and record the startup - any gearheads want to tell me what to record and I can post the data (plots). O2 sensors?, intake parms, temperatures etc.
coyote is offline   Reply With Quote
Old 01-09-2005, 12:15 AM   #4
Junior Member
Posts like a Ricer Type-R
 
Join Date: Nov 2004
Location: Los Angeles
Posts: 19
Thanks: 0
Thanked 0 Times in 0 Posts
coyote is on a distinguished road
Default

By the way chuck chuckwi11, what'* a "K&N Diop In"
coyote is offline   Reply With Quote
Old 01-09-2005, 08:27 AM   #5
Member
Posts like a V-Tak
 
Join Date: Nov 2004
Location: Daytona
Posts: 73
Thanks: 0
Thanked 0 Times in 0 Posts
chuckwi11 is on a distinguished road
Default

A "K&N DROP in" is a replacement air filter for the stock air box.
chuckwi11 is offline   Reply With Quote
Old 01-09-2005, 04:28 PM   #6
Junior Member
Posts like a Ricer Type-R
 
Join Date: Nov 2004
Location: Los Angeles
Posts: 19
Thanks: 0
Thanked 0 Times in 0 Posts
coyote is on a distinguished road
Default

Does it make a noticable difference? or do you need a dyno to tell?
coyote is offline   Reply With Quote
Old 01-10-2005, 07:47 AM   #7
Member
Posts like a V-Tak
 
Join Date: Nov 2004
Location: Daytona
Posts: 73
Thanks: 0
Thanked 0 Times in 0 Posts
chuckwi11 is on a distinguished road
Default

Don't know how it would Dyno... "they" say the gain is 5-10HP. I noticed a little better throttle response and maybe a little better MPG. Overall, I think it'* better.
chuckwi11 is offline   Reply With Quote
 
 
Reply

Related Topics
Thread Thread Starter Forum Replies Last Post
Rough Idle, Gas to Start, Flashing ECC, SES Sully1742 1992-1999 3 11-22-2006 03:01 PM
rough idle/surging after start...stumbles when driving movintons 1992-1999 21 12-11-2004 04:26 PM
From rough idle to high idle randman1 1992-1999 25 09-07-2004 09:20 PM
Ignition/fuel problem (hard start/stalls/rough idle) 1992 trofeo 1992-1999 43 04-02-2004 05:24 PM
'00SSEi:rough idle,high idle...Please Help.... GTP2SSEi General GM Chat 2 07-29-2003 01:46 PM


Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off



All times are GMT -4. The time now is 02:52 AM.


We are a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for us to earn fees by linking to Amazon.com and affiliated sites.