1988 - 1998 (GMT400) Section for all discussion related to the 1987-1998 Chevrolet and GMC trucks.

Ac idle question

Thread Tools
 
Search this Thread
 
Old May 25, 2020 | 8:38 AM
  #1  
Adrian Blanco's Avatar
Thread Starter
CF Beginner
 
Joined: May 2020
Posts: 3
Likes: 0
From: Texas
Default Ac idle question

Hi everyone, new to the forum. I have a 93 Chevy 1500 5.7 with manual transmission. Truck runs and idles great at 750 rpm but when I turn on the AC my idle will drop down to 500 rpm. Is this normal or should it maintain my 750 rpm? This sounds like something isn't right. Thanks in advance.
Reply
Old May 25, 2020 | 8:39 AM
  #2  
kevinkpk's Avatar
CF Monarch
10 Year Member
Liked
 
Joined: Jul 2011
Posts: 5,920
Likes: 140
From: kevinkpk
Default

Originally Posted by Adrian Blanco
Hi everyone, new to the forum. I have a 93 Chevy 1500 5.7 with manual transmission. Truck runs and idles great at 750 rpm but when I turn on the AC my idle will drop down to 500 rpm. Is this normal or should it maintain my 750 rpm? This sounds like something isn't right. Thanks in advance.
It should not drop the rpm.
Reply
Old May 25, 2020 | 10:03 AM
  #3  
Adrian Blanco's Avatar
Thread Starter
CF Beginner
 
Joined: May 2020
Posts: 3
Likes: 0
From: Texas
Default

Any idea why it drops?
Reply
Old May 25, 2020 | 10:50 AM
  #4  
tech2's Avatar
Super Moderator
 
Joined: Mar 2011
Posts: 9,175
Likes: 521
Default

what type of fuel injection system does it use? throttle body, spider, multiport? idle speed is controlled differently depending on the build. if you have an iac valve...it should open more when the ac is turned on
Reply
Old May 25, 2020 | 11:08 AM
  #5  
Adrian Blanco's Avatar
Thread Starter
CF Beginner
 
Joined: May 2020
Posts: 3
Likes: 0
From: Texas
Default

Originally Posted by tech2
what type of fuel injection system does it use? throttle body, spider, multiport? idle speed is controlled differently depending on the build. if you have an iac valve...it should open more when the ac is turned on
Tbi. It has an IAC.
Reply
Old May 25, 2020 | 11:13 AM
  #6  
tech2's Avatar
Super Moderator
 
Joined: Mar 2011
Posts: 9,175
Likes: 521
Default

maybe the iac port is blocked,the iac valve is stuck or the iac is not getting power
Reply
Related Topics
Thread
Thread Starter
Forum
Replies
Last Post
aahamed
General Tech
0
Feb 24, 2018 10:14 AM
JohnOH327
S-10 & Blazer
1
Jun 19, 2015 3:20 PM
burrell22
S-10 & Blazer
0
Aug 9, 2013 1:19 PM
Mldierdorff
Cobalt
1
Apr 25, 2013 5:49 PM
chaser
S-10 & Blazer
5
Apr 11, 2010 5:27 PM




All times are GMT -5. The time now is 9:00 PM.