Pennock's Fiero Forum
  Technical Discussion & Questions
  3800 completed but is idling at almost 1700 rpm. help me slow her down!!!

Post New Topic  Post A Reply
Email This Page to Someone! | Printable Version


next newest topic | next oldest topic
3800 completed but is idling at almost 1700 rpm. help me slow her down!!! by lilrifleman1200
Started on: 07-06-2012 11:59 AM
Replies: 13 (242 views)
Last post by: druddle on 10-06-2013 01:32 PM
lilrifleman1200
Member
Posts: 111
From: Carrollton,Georgia,usa
Registered: Aug 2008


Feedback score: N/A
Leave feedback

Rate this member

Report this Post07-06-2012 11:59 AM Click Here to See the Profile for lilrifleman1200Click Here to visit lilrifleman1200's HomePageClick Here to Email lilrifleman1200Send a Private Message to lilrifleman1200Edit/Delete MessageReply w/QuoteDirect Link to This Post
3800 completed but is idling at almost 1700 rpm. i have checked all the vacuum lines and fluids i have no air leaks and the throttle body is working just fine. cant this me a computer problem???
IP: Logged
PFF
System Bot
phonedawgz
Member
Posts: 17011
From: Green Bay, WI USA
Registered: Dec 2009


Feedback score:    (23)
Leave feedback





Total ratings: 290
Rate this member

Report this Post07-06-2012 01:43 PM Click Here to See the Profile for phonedawgzClick Here to visit phonedawgz's HomePageClick Here to Email phonedawgzSend a Private Message to phonedawgzEdit/Delete MessageReply w/QuoteDirect Link to This Post
Sure it could. You should start by removing the IAC and then inserting your finger to fully seal off the passage that has vacuum on it. Does the engine stall, or run well below idle speed? If so then you know the problem is the IAC pintle too retracted. The next question will be is the problem caused by the IAC, the PCM to IAC wiring, or directed by the PCM itself.

If sealing the IAC with your finger however does not slow down your idle speed, then you need to look for either a vacuum leak or a non-fully closed throttle
IP: Logged
lilrifleman1200
Member
Posts: 111
From: Carrollton,Georgia,usa
Registered: Aug 2008


Feedback score: N/A
Leave feedback

Rate this member

Report this Post07-10-2012 09:04 PM Click Here to See the Profile for lilrifleman1200Click Here to visit lilrifleman1200's HomePageClick Here to Email lilrifleman1200Send a Private Message to lilrifleman1200Edit/Delete MessageReply w/QuoteDirect Link to This Post
i took off the IACand placed my thumb over it and still had a high idle i also replaced the IAC and its still running at 1700 rpm. then i put vac plugs on all the vacuum lines and ports and still no change... i am completely stumped at this point
IP: Logged
Ryanstalin
Member
Posts: 300
From: Phenix city, Al, usa
Registered: Jan 2012


Feedback score: N/A
Leave feedback

Rate this member

Report this Post07-10-2012 09:07 PM Click Here to See the Profile for RyanstalinClick Here to Email RyanstalinSend a Private Message to RyanstalinEdit/Delete MessageReply w/QuoteDirect Link to This Post
could a bad map cause this, and/or egr valve being stuck open?
IP: Logged
lilrifleman1200
Member
Posts: 111
From: Carrollton,Georgia,usa
Registered: Aug 2008


Feedback score: N/A
Leave feedback

Rate this member

Report this Post07-10-2012 09:15 PM Click Here to See the Profile for lilrifleman1200Click Here to visit lilrifleman1200's HomePageClick Here to Email lilrifleman1200Send a Private Message to lilrifleman1200Edit/Delete MessageReply w/QuoteDirect Link to This Post
i was thinking that also so i took them both off and did a delete on both... same issue... so i put them back on.
IP: Logged
crashyoung
Member
Posts: 1324
From: Lowell, Michigan, USA
Registered: May 2012


Feedback score: N/A
Leave feedback

Rate this member

Report this Post07-10-2012 10:36 PM Click Here to See the Profile for crashyoungClick Here to Email crashyoungSend a Private Message to crashyoungEdit/Delete MessageReply w/QuoteDirect Link to This Post
Did you plug the large hoses on the manifold? one is the PVC, the other is for the brake booster. Then there are the vapor recovery lines...
IP: Logged
Mike Gonzalez
Member
Posts: 5093
From: Colorado Springs, CO. USA
Registered: Jul 2001


Feedback score: (1)
Leave feedback





Total ratings: 130
Rate this member

Report this Post07-10-2012 11:12 PM Click Here to See the Profile for Mike GonzalezClick Here to Email Mike GonzalezSend a Private Message to Mike GonzalezEdit/Delete MessageReply w/QuoteDirect Link to This Post
Are you sure the throttle cable is allowing the TB to close all the way ?
IP: Logged
phonedawgz
Member
Posts: 17011
From: Green Bay, WI USA
Registered: Dec 2009


Feedback score:    (23)
Leave feedback





Total ratings: 290
Rate this member

Report this Post07-10-2012 11:52 PM Click Here to See the Profile for phonedawgzClick Here to visit phonedawgz's HomePageClick Here to Email phonedawgzSend a Private Message to phonedawgzEdit/Delete MessageReply w/QuoteDirect Link to This Post
For the engine to run at 1700 rpm, somehow air is getting into the intake manifold. Vacuum lines disconnected are not going to get you to that speed, with perhaps the exception of the large vacuum brake booster line.

You covered the IAC hole and the engine still ran fast. That eliminates the IAC, the IAC wiring, the PCM and any electronic sensors.

Is your throttle closing completely?

Did you eliminate the EGR valve and not fully seal the hole in the lower intake manifold?

IP: Logged
Pappy
Member
Posts: 842
From: Land of Confusion
Registered: Apr 2010


Feedback score: (1)
Leave feedback

Rate this member

Report this Post07-11-2012 01:29 AM Click Here to See the Profile for PappySend a Private Message to PappyEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by Mike Gonzalez:

Are you sure the throttle cable is allowing the TB to close all the way ?


x2 and check for interference issues front to back cable wise

[This message has been edited by Pappy (edited 07-11-2012).]

IP: Logged
darkhorizon
Member
Posts: 12232
From: Flint Michigan
Registered: Jan 2006


Feedback score: (1)
Leave feedback





Total ratings: 450
Rate this member

Report this Post07-11-2012 12:20 PM Click Here to See the Profile for darkhorizonSend a Private Message to darkhorizonEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by lilrifleman1200:

i took off the IACand placed my thumb over it and still had a high idle i also replaced the IAC and its still running at 1700 rpm. then i put vac plugs on all the vacuum lines and ports and still no change... i am completely stumped at this point


I doubt your thumb could have fit way down in the hole. to block the IAC passage you have to jam something all the way down the hole and seal it off completely.
IP: Logged
druddle
Member
Posts: 15
From: Clarksville,tn,us
Registered: Apr 2013


Feedback score: N/A
Leave feedback

Rate this member

Report this Post10-06-2013 11:45 AM Click Here to See the Profile for druddleClick Here to Email druddleSend a Private Message to druddleEdit/Delete MessageReply w/QuoteDirect Link to This Post
I have a very similar problem , I have put a new IAC on no change
I also checked for manifold leaks and throttle body leaks. Also throttle cable
Still no change. Did you ever find your problem?
IP: Logged
PFF
System Bot
FIEROFLYER
Member
Posts: 3971
From:
Registered: Oct 2002


Feedback score:    (13)
Leave feedback





Total ratings: 178
Rate this member

Report this Post10-06-2013 01:27 PM Click Here to See the Profile for FIEROFLYERSend a Private Message to FIEROFLYEREdit/Delete MessageReply w/QuoteDirect Link to This Post
I would say double check the IAC again and make sure you are plugging it off completely as well as make sure the throttle is not being kept open some by the cable set up. If not check for vac leaks around the throttle body to manifold gasket and you did plug the larger vac port for the brake booster as I had one a few years ago with a small hole in the metal brake booster tube going through the car that was very hard to track down. Dan
IP: Logged
lilrifleman1200
Member
Posts: 111
From: Carrollton,Georgia,usa
Registered: Aug 2008


Feedback score: N/A
Leave feedback

Rate this member

Report this Post10-06-2013 01:29 PM Click Here to See the Profile for lilrifleman1200Click Here to visit lilrifleman1200's HomePageClick Here to Email lilrifleman1200Send a Private Message to lilrifleman1200Edit/Delete MessageReply w/QuoteDirect Link to This Post
Mine only does it after I drive it. Like after it's all nice and warm it won't slow down.
IP: Logged
druddle
Member
Posts: 15
From: Clarksville,tn,us
Registered: Apr 2013


Feedback score: N/A
Leave feedback

Rate this member

Report this Post10-06-2013 01:32 PM Click Here to See the Profile for druddleClick Here to Email druddleSend a Private Message to druddleEdit/Delete MessageReply w/QuoteDirect Link to This Post
I have a very similar problem , I have put a new IAC on no change
I also checked for manifold leaks and throttle body leaks. Also throttle cable
Still no change. Did you ever find your problem?
IP: Logged

next newest topic | next oldest topic

All times are ET (US)

Post New Topic  Post A Reply
Hop to:

Contact Us | Back To Main Page

Advertizing on PFF | Fiero Parts Vendors
PFF Merchandise | Fiero Gallery | Ogre's Cave
Real-Time Chat | Fiero Related Auctions on eBay



Copyright (c) 1999, C. Pennock