It is currently Fri Feb 23, 2018 10:20 pm

All times are UTC - 5 hours [ DST ]




Post new topic Reply to topic  [ 5 posts ] 
Author Message
 Post subject: Persistent High Idle
PostPosted: Wed Aug 23, 2017 1:11 am 
Offline
LE Member

Joined: Thu Aug 04, 2011 1:16 pm
Posts: 6
Year and Trim: 1997 Bonneville SE
97 Bonneville SE, 250K original miles, this car has been a real champion of longevity with little more than routine care and maintenance. Its been a Florida car its whole life. Right now I'm :banghead:

The car has been idling high at startup for over a year, as high as 2800 rpm. The rpm will increase with electrical load, (turning on the A/C, headlights, etc) and (usually) drop when removing the electrical loads. The car will idle high when coming to a stop light and will usually drop to normal when coming to a complete stop though sometimes I'll have to turn off the A/C to get it to drop. Looking at the Idle Air Controller with Torque Pro, it can read as high as 122 counts out of 255, which let's me drive in 4th gear at 50mph without touching the gas pedal sometimes. Normal idle, around 800 rpm with the A/C on, is around 50-70 counts. The IAC is doing what the PCM is telling it to do. But why?

The car is at the shop and the (competent) mechanic, and myself, are stumped.

IAC, PCM, ICM, EGR valve, LIM and UIM, Valve cover gaskets, and Throttle Body have been replaced with new or from known good, running engines. No vacuum leaks have been found. The PCM is NOT throwing a DTC P0507 Idle Control System HIGH RPM code.

Please help.


Top
 Profile  
 
 Post subject: Re: Persistent High Idle
PostPosted: Wed Aug 23, 2017 7:22 am 
Offline
Posts like an L67
Posts like an L67

Joined: Sun Aug 22, 2010 11:11 pm
Posts: 1380
Location: Ontario, Canada
Year and Trim: 2000 Bonniville SSEi L67
hi, I would first try unplugging the MAF sensor and see if the issue changes. I would also inspect the throttle plate and linkage to be sure it closes properly. give that a try.
cheap and easy!!

_________________
poverty forces one to do unorthodox things

2000 SSEi
past rides:
1996 SSEi
1992 GTP
1987 Grand Am


Top
 Profile  
 
 Post subject: Re: Persistent High Idle
PostPosted: Wed Aug 23, 2017 8:42 pm 
Offline
LE Member

Joined: Thu Aug 04, 2011 1:16 pm
Posts: 6
Year and Trim: 1997 Bonneville SE
MAF has been unplugged and the throttle plate and linkage have been changed/checked with no change in the high idle situation.


Top
 Profile  
 
 Post subject: Re: Persistent High Idle
PostPosted: Fri Aug 25, 2017 8:44 pm 
Offline
Posts like an L67
Posts like an L67

Joined: Sun Aug 22, 2010 11:11 pm
Posts: 1380
Location: Ontario, Canada
Year and Trim: 2000 Bonniville SSEi L67
ok, I would next move to throttle position sensor. see what it reads at Key On Engine Off, and idle. with the tb being replaced, you might need a reset/ relearn to 0%. I would put koeo, and unplug the tps. turn key off. plug in tps and start car. - is tp at 0% at idle

_________________
poverty forces one to do unorthodox things

2000 SSEi
past rides:
1996 SSEi
1992 GTP
1987 Grand Am


Top
 Profile  
 
 Post subject: Re: Persistent High Idle
PostPosted: Fri Sep 29, 2017 5:49 pm 
Offline
Retired Admin/Techinfo Admin
Retired Admin/Techinfo Admin

Joined: Mon May 19, 2008 2:08 pm
Posts: 26000
Location: Space Coast, or at least it used to be
Year and Trim: 03 SLE, 95 SE, 95 TS SE
I know I'm late to this ball game... But I would check and see if there are any Transmission Range Switch failure codes


Top
 Profile  
 
Display posts from previous:  Sort by  
Post new topic Reply to topic  [ 5 posts ] 

All times are UTC - 5 hours [ DST ]


Related topics
 Topics   Author   Replies   Views   Last post 
There are no new unread posts for this topic. High idle - TPS?

[ Go to pageGo to page: 1, 2 ]

Marmot

26

7587

Sat Sep 27, 2008 10:40 am

bad.moshi View the latest post

There are no new unread posts for this topic. High Idle

milty

3

1394

Fri Jul 16, 2010 4:01 pm

J Wikoff View the latest post

There are no new unread posts for this topic. High Idle

robertccach

1

857

Mon Nov 01, 2010 5:43 pm

i<3bonbons View the latest post

There are no new unread posts for this topic. Idle too high on hot starts

teleplayer

5

1938

Wed Sep 17, 2008 6:16 pm

bad.moshi View the latest post

There are no new unread posts for this topic. High Idle and No 4th gear

aklbeach

1

349

Fri Feb 28, 2014 12:07 am

bad.moshi View the latest post

 


Who is online

Users browsing this forum: No registered users and 4 guests


You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot post attachments in this forum

Search for:
Jump to:  
Powered by phpBB® Forum Software © phpBB Group


phpBB SEO