Go Back  Offshoreonly.com > Technical > General Q & A
454 mag mpi won't idle >

454 mag mpi won't idle

Notices

454 mag mpi won't idle

Thread Tools
 
Old 06-11-2012 | 08:45 AM
  #1  
Thread Starter
Registered
15 Year Member
 
Joined: Mar 2010
Posts: 562
Likes: 2
From: Roscoe, IL
Default 454 mag mpi won't idle

I was out this weekend and left the dock and went to the sand bar (everything was all good), went to leave the sand bar and the port side motor wouldn't idle. Decided to go back to the dock, no loss of power it ran fine off of idle and got to the dock and still wouldnt idle. Checked fuel pressure, it was good. Check that the idle screw, it hadn't back out it was good. I could get it to idle at 650 rpm if I bumped the throttle a little, almost like the idle screw had backed out but not the case. Went to fire it up to check one last thing and it idled perfect. Any ideas, iac motor, tps sensor, map sensor, or do I need to clean any of the? Any inpute would be helpfull. Thanks Eric
Esal is offline  
Reply
Old 06-11-2012 | 09:03 AM
  #2  
Registered
 
Joined: Nov 2006
Posts: 974
Likes: 4
From: Boca Raton, FL
Default

It could be any of the above but usually the IAC is the culprit--do you hear the "hissing" sound at idle? Have your computer scanned before you start buying parts.
Powerquest_Baby!! is offline  
Reply
Old 06-11-2012 | 10:34 AM
  #3  
Thread Starter
Registered
15 Year Member
 
Joined: Mar 2010
Posts: 562
Likes: 2
From: Roscoe, IL
Default

There was a lot more intake noise out of that motor compared to the other one. It was a hissing type noise.
Esal is offline  
Reply
Old 06-11-2012 | 10:37 AM
  #4  
Registered
10 Year Member
 
Joined: Feb 2012
Posts: 4,031
Likes: 10
From: westville, NJ
Default

iac stuck wide open. that is hissing noise.
dereknkathy is offline  
Reply
Old 06-11-2012 | 11:21 AM
  #5  
Registered
 
Joined: Jan 2004
Posts: 4,480
Likes: 43
From: Tennessee
Default

Pull the IAC out and clean it. They get gummed up with carbon/oil. Take it out and wipe the pintle with some carb and choke cleaner. Also wipe out the passage that the IAC sits in. It will be full of gunk as well. That should fix your problem. I would say the IAC got stuck. Once the crude heated up a little it broke free.
Eddie
Young Performance is offline  
Reply
Old 06-11-2012 | 02:08 PM
  #6  
Thread Starter
Registered
15 Year Member
 
Joined: Mar 2010
Posts: 562
Likes: 2
From: Roscoe, IL
Default

Thanks for all the help I will clean the iac and then get a spare to have on the boat.
Esal is offline  
Reply

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 On
Pingbacks are On
Refbacks are On



Contact Us - Archive - Advertising - Cookie Policy - Privacy Statement - Terms of Service

Copyright © 2026 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.