Go Back  Offshoreonly.com > Technical > General Q & A
Weird engine shut down last night 502 MPI >

Weird engine shut down last night 502 MPI

Notices

Weird engine shut down last night 502 MPI

Old 07-23-2013, 09:31 AM
  #11  
Registered
 
28Eliminator's Avatar
 
Join Date: Dec 2001
Location: Rapid City SD
Posts: 809
Likes: 0
Received 0 Likes on 0 Posts
Default

I have fixed many boats with the exact problem you are having, and I can tell you that it can be a bad connection almost anywhere in the run circuit. Grounds are always on the top of the list as well as the kill switch. If it's a 96 that is the first thing I would change. I have found loose connections on the ignition switch, battery, main harness connector on the motor, and most recently a loose power wire on the alternator. I would also check the obvious; ie, Starter wires, big RED breaker wires on motor, grounds. If the ECU gets a drop in power for any small period of time it resets, basically killing the motor.
28Eliminator is offline  
Old 07-23-2013, 01:49 PM
  #12  
Registered
 
Join Date: Jul 2012
Posts: 21
Received 0 Likes on 0 Posts
Default

I had a similar issue with the 502 in my 96 Formula; the motor would stumble at high rpm in rough water. Check the wiring harness that runs between the rear of the motor and the oil cooler. You may need to remove the mounting bolts for the VST and move the VST out of the way to see the problem. The main power wire, I believe that it is 10 gauge, has a non-insulated butt connector that is wrapped with cloth tape; the butt connector wears through the tape and it intermittently shorts out to the engine block. I wrapped mine with good quality electrical tape and covered the wiring harness with split wire loom to prevent the problem from occurring again. Hope this helps.
GMC271 is offline  
Old 07-23-2013, 02:19 PM
  #13  
Registered
Thread Starter
 
Join Date: Jun 2004
Location: Sun Prairie, WI
Posts: 1,128
Likes: 0
Received 13 Likes on 9 Posts
Default

Doesn't sound the same actually. Mine doesn't stumble at all. Just shuts off like turning the key off. I'm currently working on changing out the ignition switch, kill switch, checking main engine connector, and checking/cleaning main ground on the back of the block.
cloudmaster_321 is offline  
Old 08-07-2013, 11:40 AM
  #14  
Registered
Thread Starter
 
Join Date: Jun 2004
Location: Sun Prairie, WI
Posts: 1,128
Likes: 0
Received 13 Likes on 9 Posts
Default

Well guys, Ignition switch has been changed, kill switch changed. Rang out the kill switch wiring to the ecm, no problems. Also took a look at the key on as was suggested, it originates from the "ignition on" buss. I have found that my older fuse panel with the agc type fuses can be intermittent. Such as my cabin lighting not working, and i'll spin the fuse in the holder and the lights come back on. So I took some contact cleaner and a horsehair brush and cleaned the ignition buss and fuse. I've run the boat for 7 hours since, and hard, with no problems. I may end up changing out the fuse buss system to a new style blade type.

That's all for now.....
cloudmaster_321 is offline  

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 © 2024 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.