Go Back   F150online Forums > F-Series Trucks > Pre-1997 Models
Sign in using an external account
Register Forgot Password?

Pre-1997 Models

Welcome to F150Online Forums!
Welcome to F150Online.com.

You are currently viewing our forums as a guest, which gives you limited access to view most discussions and access our other features. By joining our community you will have access to post topics, communicate privately with other members (PM), respond to polls, upload content and access many other special features. Registration is fast, simple and absolutely free so please, join the F150Online Forums community today!





Reply
 
 
 
 
Thread Tools Search this Thread Display Modes
  #1  
Old 03-09-2011, 02:17 PM
Junior Member
 
Join Date: Feb 2011
Posts: 6
Weird Timing issue on a 86 I6 300cui

so rebuilt my spare distributor for my truck, new pickup, rotor, cap and case and vacuum advance module and have the weirdest thing happening

we set the timing to 10 degrees BDTC (originally tried 14 but then we got this problem so went back to stock adjustments) and all is well, UNTIL we connect the vacuum advance, then the rpm's drop and it sputters and wants to die out and idles really low, its got fresh wires and fairly new plugs and runs fine right until you connect the vacuum line. we ruled out weird vacuum issues since if we disconnect the hose and actuate the advance on its own it does the same thing. the truck is a bit of a hack job from the previous owner but everything looks to be hooked the same as the parts truck that i took the rebuild dist from (couldn't test with the old dist because the advance on it was broken thus the need for the new unit)

anyone experience something like this before?
__________________
1986 F150 4x4 STD Cab Long Box, 4.9L stock carb,intake and exhaust. 4 Speed Manual (with bull low)
Reply With Quote
  #2  
Old 03-09-2011, 02:22 PM
Senior Member
 
Join Date: May 1999
Location: Copley, Ohio
Vehicle: 1996 Ford F150
Posts: 2,477
Are you sure you're using the right set of timing marks?
I'm not certain where the correct ones are on an 86 but I know that the ones cast into the timing gear cover are the wrong ones on an EFI truck. If you're using the ones on the front cover, look for another set on a metal tab at about 9:00 on the passenger side and see if those work better.
__________________
1996 F-150 XLT, reg. cab 6.5' box, 4.9 I6. E4OD w/ B&M alum sump, auxiliary cooler and external filter, Addco 1" sway-bars F&R, Bilstein shocks, 16 x 8 AR Bajas w/255/70-16s, Line-X spray in liner, hinged tonneau, Reese hitch and electric brake controller, VDO tranny and engine oil temp gages, stainless pushbar, Hella 550 fog and driving lights, Hella backup/work lights, 3.73 Trac-Lok w/ an alum. diff. cover with cap support screws, PFC "Z" brake pads, high flow cat with a 2.5" cat back with a FM 70 muffler.
Reply With Quote
  #3  
Old 03-09-2011, 02:24 PM
Junior Member
 
Join Date: Feb 2011
Posts: 6
we cleaned everything up and are using the right ones on the passenger side front.
its not a EFI truck its the 1 barrel carb motor. (may be switching to a 4barrel carb and intake seutp in the not to distant future)
__________________
1986 F150 4x4 STD Cab Long Box, 4.9L stock carb,intake and exhaust. 4 Speed Manual (with bull low)
Reply With Quote
  #4  
Old 03-09-2011, 02:31 PM
Junior Member
 
Join Date: Feb 2011
Posts: 6
also should note we swapped in a spare coil and duraspark unit i had from my parts truck and same issue (though both coils could have issues, but it runs fine without the advance)
__________________
1986 F150 4x4 STD Cab Long Box, 4.9L stock carb,intake and exhaust. 4 Speed Manual (with bull low)
Reply With Quote
  #5  
Old 03-09-2011, 06:24 PM
glc glc is online now
Senior Member
 
Join Date: Dec 2006
Location: Joplin MO
Vehicle: 2003 Ford F150
Posts: 28,506
Sounds like you have the vacuum advance backwards/upside down and it's retarding rather than advancing. Either that or it's a dual advance/retard mechanism with 2 vacuum ports and you have the hoses crossed.
__________________
2003 F-150 XL RCSB 2wd 4.2 M5OD 3.55 LS
Reply With Quote
  #6  
Old 03-11-2011, 05:01 PM
Senior Member
 
Join Date: Dec 2004
Location: poquoson virginia
Vehicle: 1981 ford bronco
Posts: 1,079
You have the wrong vacuum source. 86 came with a feedback carb with a tfi distributor. Sounds like someone changed it to a duraspark system. Not a big deal, I did the same with the 86 that I had. You need to find a "ported" vacuum source, one that does not have vacuum until the engine is revved up. Vacuum at idle will cause the advance to actuate. That's the reason it doesn't run right. Take a look where the distributor vacuum is hooked up to the carb on an 80 to 83 six cylinder
Reply With Quote
Old 03-11-2011, 05:01 PM


 
 
 
Reply

Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

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 Off
Pingbacks are On
Refbacks are Off


All times are GMT -4. The time now is 07:04 PM.


 
This forum is owned and operated by Internet Brands, Inc., a Delaware corporation. It is not authorized or endorsed by the Ford Motor Company and is not affiliated with the Ford Motor Company or its related companies in any way. FordŽ is a registered trademark of the Ford Motor Company
Contact Us Advertising Privacy Statement Terms of Service Jobs Forum Text Archives
Emails & Contact Details