Fast idle after changing UIM - GM Forum - Buick, Cadillac, Chev, Olds, GMC & Pontiac chat


1992-1999 Series I L27 (1992-1994 SE,SLE, SSE) & Series II L36 (1995-1999 SE, SSE, SLE) and common problems for the Series I and II L67 (all supercharged models 92-99) Including Olds 88's, Olds LSS's and Buick Lesabres Please use General Chat for non-mechanical issues, and Performance and Brainstorming for improvements.

Reply
 
 
 
Thread Tools Search this Thread
Old 11-14-2006, 10:24 PM   #1
Member
Posts like a V-Tak
Thread Starter
 
Join Date: Oct 2006
Location: Indy
Posts: 69
Thanks: 0
Thanked 0 Times in 0 Posts
Bigfoot is on a distinguished road
Default Fast idle after changing UIM

Well, I bit the bullet and replaced the UIM with the APN model with the sleeved EGR opening and reduced diameter EGR stovepipe. I also changed the gaskets on the LIM. Then flushed the cooling system. That all went well but....

Now I have a fast idle (1500 in neutral, 1100 in drive). Also have codes 107 and 108, and 121 (low manifold and high manifold pressure). I have checked for vacuum leaks by spraying Gumout around the UIM and throttle body but no change in idle.

Any thoughts?

Also, my serpentine belt now slips when warm. It was new about 1 year ago. Any tricks short of replacing it? I heard to avoid belt dressings, but dishwashing soap helps?? I am not ready to try that unless I have a new one in my hand.
Bigfoot is offline   Reply With Quote
Old 11-14-2006, 10:51 PM   #2
PopaDopaDo
True Car Nut
 
popatim's Avatar
 
Join Date: Jan 2005
Location: NY
Posts: 4,957
Thanks: 0
Thanked 0 Times in 0 Posts
popatim is on a distinguished road
Default

I'd start with insuring the sensors are plugged in and cleaning the grounds.
popatim is offline   Reply With Quote
Old 11-14-2006, 11:27 PM   #3
Junior Member
Posts like a Ricer Type-R
 
Join Date: Aug 2002
Posts: 10
Thanks: 0
Thanked 0 Times in 0 Posts
willwren is on a distinguished road
Default

At idle, remove the oil fill cap. Sucking? If so, you missed an o-ring on your PCV valve.
willwren is offline   Reply With Quote
Old 11-15-2006, 02:46 AM   #4
Senior Member
True Car Nut
 
Join Date: Mar 2004
Location: Ames, Iowa
Posts: 3,066
Thanks: 0
Thanked 1 Time in 1 Post
bill buttermore is on a distinguished road
Default

If it'* not the PCV, check the idle air control.

On the slipping belt. De-tension the belt and slip it off the alternator. Spin all the pulleys by hand. If the pulleys all look good, and spin normally (no drag), you may need a new tensioner.

You can check belt tension with a relatively inexpensive gauge called a "Clikit." You need to get the right one for the range you want to read. They cost about $15.

My '95 FSM says the belt tension on your belt should be between 50 and 70 pounds taken as the average of three readings. Measure tension midway between the generator and the ps pump. The three readings are taken after the engine is stopped and:

1. With engine warmed up and no accessories on
2. After tightening (clockwise) and releasing the tensioner
3. After loosening (counter-clockwise) and slowly re-applying tension.
bill buttermore is offline   Reply With Quote
Old 11-16-2006, 08:50 PM   #5
Member
Posts like a V-Tak
Thread Starter
 
Join Date: Oct 2006
Location: Indy
Posts: 69
Thanks: 0
Thanked 0 Times in 0 Posts
Bigfoot is on a distinguished road
Default

Willwren hit the nail on the head. We could hardly remove the oil filler cap with the engine running due to the vacuum.

So yes, we were missing not just the o-ring, but the PCV altogether!

As far as my slipping belt; I checked the alternator, water pump, power steering pump, and idler pully and everything spins easily. The tensioner takes a breaker bar to get it to release the tension enough to get the belt off. So I am about at the point of replacing the belt. I am thinking that coolant got on it when I flushed the system.

Any tricks on getting the front engine mount off so I can get the belt off?
Bigfoot is offline   Reply With Quote
Old 11-16-2006, 11:12 PM   #6
Senior Member
True Car Nut
 
Join Date: Mar 2004
Location: Ames, Iowa
Posts: 3,066
Thanks: 0
Thanked 1 Time in 1 Post
bill buttermore is on a distinguished road
Default

Quote:
Originally Posted by Bigfoot
Willwren hit the nail on the head. We could hardly remove the oil filler cap with the engine running due to the vacuum.

So yes, we were missing not just the o-ring, but the PCV altogether!

As far as my slipping belt; I checked the alternator, water pump, power steering pump, and idler pully and everything spins easily. The tensioner takes a breaker bar to get it to release the tension enough to get the belt off. So I am about at the point of replacing the belt. I am thinking that coolant got on it when I flushed the system.

Any tricks on getting the front engine mount off so I can get the belt off?
You only need to remove one bolt from the mount and slide the sleeve out to replace the belt. Do a search - explained many times - with pix, too.

Here'* one:

http://www.bonnevilleclub.com/forum/...ic.php?t=25394

Here'* a pic:

Name:  L36beltchg.jpg
Views: 2
Size:  108.0 KB
bill buttermore is offline   Reply With Quote
Old 11-17-2006, 08:24 AM   #7
Member
Posts like a V-Tak
Thread Starter
 
Join Date: Oct 2006
Location: Indy
Posts: 69
Thanks: 0
Thanked 0 Times in 0 Posts
Bigfoot is on a distinguished road
Default

Bill B: Great picture. I checked the other threads as you advised and it appears fairly straighforward. Looks like I need to buy an E10 torx socket and just do it.

I have the factory service manual and now that I have read these threads it agrees with only needing to remove the bottom mount spacer. BUT, obviously the tech writer was not a mechanic, or the writer was a mechanic and not a tech writer - very obtuse.

I tried this a couple of years ago and gave up. Landed up paying a mechanic $100 labor to install my belt.

Wish I had found this forum a few years back. You guys have all of the answers.

Bigfoot is offline   Reply With Quote
Old 11-17-2006, 08:10 PM   #8
Senior Member
Posts like a 4 Banger
 
Join Date: Oct 2006
Posts: 141
Thanks: 0
Thanked 0 Times in 0 Posts
motorhead is on a distinguished road
Default

A missing PCV valve can create a high pitched whistle noise from the engine. Are you sure it'* the belt making the noise or is it the missing PCV?
motorhead is offline   Reply With Quote
Old 11-18-2006, 02:48 PM   #9
Member
Posts like a V-Tak
Thread Starter
 
Join Date: Oct 2006
Location: Indy
Posts: 69
Thanks: 0
Thanked 0 Times in 0 Posts
Bigfoot is on a distinguished road
Default

We still had the noise after replacing the PCV. But I put a 3rd coat of STP belt dressing and the noise ended. So I am happy to avoid changing the serpentine belt at this time.
Bigfoot is offline   Reply With Quote
 
 
Reply

Related Topics
Thread Thread Starter Forum Replies Last Post
1993 LeSabre Idle Rough after Code 18 After Repairs Kimberly Buick 24 06-17-2015 05:25 PM
Trans am rough idle after changing water pump TheBeastlyTA Performance, Brainstorming & Tuning 10 11-14-2013 05:51 PM
RPM's at warm idle little high after UIM replacement billha 1992-1999 8 05-22-2011 09:09 AM
UIM and LIM replaced now leaking coolant out of UIM gasket Paul1981 2000-2005 10 12-21-2007 11:05 PM
Regular "miss" in idle after UIM/LIM job Must_Wrench 1992-1999 38 08-25-2007 11:16 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 05:06 PM.


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.