Home 
Home Search search Menu menu Not logged in - Login | Register

 Moderated by: Greg Fletcher
New Topic Reply Printer Friendly
Misfire  Rate Topic 
AuthorPost
 Posted: 11-02-2015 01:12 am
  PM Quote Reply
1st Post
blawrence
Member
 

Joined: 12-08-2009
Location: North Carolina USA
Posts: 23
Status: 
Offline
1973 JH running well after rebuilding carbs and installing new timing gears and belt, until today. Suddenly misfiring on #4. Strobe light fine on 12 and 3, but intermittent or not at all on 4. Plugs cleaned and checked. Strobe light up and good spark when plug is removed and laying on cam cover. Any ideas would be helpful.

Back To Top PM Quote Reply  

 Posted: 11-02-2015 05:19 am
  PM Quote Reply
2nd Post
Tim Murphy
Member


Joined: 03-22-2005
Location: Huntington
Posts: 60
Status: 
Offline
Plug wire shorting out when plug installed in cylinder.

Back To Top PM Quote Reply

 Posted: 11-02-2015 06:42 am
  PM Quote Reply
3rd Post
Frank Schwartz
Member
 

Joined: 02-18-2011
Location:  
Posts: 246
Status: 
Offline
The problem could be a plug wire not plugged into the distributor cap..it is so tight under there that when you try to put the cap back on the distributor it is easy to pull a wire from the cap...personal experience...also you can check the firing with a strobe light..just connect the pickup from plug wire 1 on through four..each time just pulling the trigger on the strobe light..If it is firing, it will flash at each plug wire..if it doesn't, it is unplugged...

Also if it seem to run and back fires..check to see that you haven't cross mounted 1 and 3...or 2 and 4 wires in the distributor cap...again,personal experience.

Back To Top PM Quote Reply  

 Posted: 11-02-2015 12:25 pm
  PM Quote Reply
4th Post
blawrence
Member
 

Joined: 12-08-2009
Location: North Carolina USA
Posts: 23
Status: 
Offline
Thanks for the ideas, guys. I have removed and rechecked all connections into the petronix cap. Also replaced #4 wire with longer wire that is not under strain. Strobe light fires when plug is not in cylinder, but is erratic or dead when plug is installed. Plug set is almost new, but I will change plug, just to be sure.

Back To Top PM Quote Reply

 Posted: 11-03-2015 04:38 pm
  PM Quote Reply
5th Post
Jim Sohl sn 11210
Member
 

Joined: 01-20-2015
Location:  
Posts: 9
Status: 
Offline
Swap the plugs. See if the problem moves with the plug or stays in place

Back To Top PM Quote Reply  

 Posted: 11-03-2015 09:47 pm
  PM Quote Reply
6th Post
blawrence
Member
 

Joined: 12-08-2009
Location: North Carolina USA
Posts: 23
Status: 
Offline
Problem did move around, so a new set of plugs set to .040" have been fitted. Also needed to reset carb balance but all seems to e well again. Thanks guys!

Back To Top PM Quote Reply

Current time is 06:34 pm  
> Jensen Healey & Jensen GT Tech > Ignition > Misfire Top




UltraBB 1.172 Copyright © 2007-2011 Data 1 Systems