Go Back  Offshoreonly.com > Technical > General Q & A
Thunderbolt iv ignition sensor ground wire connection point. >

Thunderbolt iv ignition sensor ground wire connection point.

Notices

Thunderbolt iv ignition sensor ground wire connection point.

Old 09-27-2020, 01:07 PM
  #1  
Registered
Thread Starter
 
Join Date: Oct 2016
Posts: 110
Received 0 Likes on 0 Posts
Default Thunderbolt iv ignition sensor ground wire connection point.

Replacing a 28 year old Thunderbolt IV ignition sensor assembly that was 2-wire + a 3rd ground wire that was connected between the bottom of the sensor mounting screw and the TB iv module bracket mounting bolt (@ the exhaust manifold)...The moduleís ground wire was also connected to the same bolt.

The instructions for the new ignition sensor says to ground the new 3rd wire at the main flywheel ground point which is not doable without fork lifting the engine cover off. IS THE BRACKET MOUNTING POINT ON THE EXHAUST MANIFOLD AN APPROPRIATE GROUND SPOT?

Last edited by 92cobalt243; 09-27-2020 at 01:10 PM.
92cobalt243 is offline  
Old 09-27-2020, 04:19 PM
  #2  
Platinum Member
Platinum Member
iTrader: (7)
 
getrdunn's Avatar
 
Join Date: Feb 2009
Location: NW Michigan
Posts: 6,172
Received 19 Likes on 15 Posts
Default

anywhere on the block for the 3rd wire be fine. Iíd imagine their just looking for another ground source via corrosion etc. Just a guess.
getrdunn is offline  
Old 09-27-2020, 04:31 PM
  #3  
Registered
iTrader: (5)
 
Join Date: Jul 2009
Location: Taunton Ma
Posts: 7,894
Received 161 Likes on 90 Posts
Default

Originally Posted by 92cobalt243 View Post
Replacing a 28 year old Thunderbolt IV ignition sensor assembly that was 2-wire + a 3rd ground wire that was connected between the bottom of the sensor mounting screw and the TB iv module bracket mounting bolt (@ the exhaust manifold)...The moduleís ground wire was also connected to the same bolt.

The instructions for the new ignition sensor says to ground the new 3rd wire at the main flywheel ground point which is not doable without fork lifting the engine cover off. IS THE BRACKET MOUNTING POINT ON THE EXHAUST MANIFOLD AN APPROPRIATE GROUND SPOT?
how can you not reach the main ground point with the engine installed? Where is the battery cable ground connected? I doubt your ignition module bracket is bolted to the exhaust manifold. Electronics and heat donít get along well.
Unlimited jd is offline  
Old 09-27-2020, 05:17 PM
  #4  
Registered
Thread Starter
 
Join Date: Oct 2016
Posts: 110
Received 0 Likes on 0 Posts
Default

Originally Posted by Unlimited jd View Post
how can you not reach the main ground point with the engine installed? Where is the battery cable ground connected? I doubt your ignition module bracket is bolted to the exhaust manifold. Electronics and heat donít get along well.
I ďpersonallyĒ canít reach the main ground point...minimal space and Iím old...the bracket mounts to the riser/manifold joint of the emi thunder exhaust. Iíll find another spot and maybe connect the moduleís ground wire to it, too. Thanks for the input.


92cobalt243 is offline  
Old 09-27-2020, 05:59 PM
  #5  
Registered
iTrader: (5)
 
Join Date: Jul 2009
Location: Taunton Ma
Posts: 7,894
Received 161 Likes on 90 Posts
Default

I understand a bit better now. It should be fine there. Your first description made me think you had a bracket coming off the bolts that go into the head. Any secure clean spot that is metal on metal to the block should be fine for that ground.
Unlimited jd is offline  
Old 09-27-2020, 06:45 PM
  #6  
Registered
 
Join Date: Nov 2003
Posts: 276
Likes: 0
Received 51 Likes on 25 Posts
Default

i have the same cobalt hull the engine hatch is also the rear bench seat making it hard to access the back of engine i pull the hatch pin and block the hatch straight up i also switched it to the delco est dist it runs and idles better...the est,s idle with a lot of inital timing making a big block smooth
boostbros is offline  
Old 09-27-2020, 07:51 PM
  #7  
Registered
Thread Starter
 
Join Date: Oct 2016
Posts: 110
Received 0 Likes on 0 Posts
Default

Originally Posted by boostbros View Post
i have the same cobalt hull the engine hatch is also the rear bench seat making it hard to access the back of engine i pull the hatch pin and block the hatch straight up...
...yep I lift the heavy SOB and prop it straight up...I suppose it would be easier if I also removed the 2 bulkheads/walls that wreck my laying down room. I feel for boat mechanics, for sure. Thanks for the help.
92cobalt243 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 - Do Not Sell My Personal Information -

Copyright © 2018 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.