Go Back   Ford Truck Enthusiasts Forums > Older, Classic & Antique Trucks > 1967 - 1972 F-100 & Larger F-Series Trucks
Sign in using an external account
Register Forgot Password?


1967 - 1972 F-100 & Larger F-Series Trucks Discuss the Bumpsides Ford Truck

Reply
 
 
 
 
LinkBack Thread Tools Search this Thread
  #1  
Old 12-07-2000, 01:45 AM
fomojo fomojo is offline
New User
 
Join Date: Dec 2000
Posts: 2
fomojo is starting off with a positive reputation.
72 360 backfires thru carb

Help! My 72 f250 (360) starts and runs well but backfires thru the carb and loses power on upgrades at 60mph or more. Plug wires are new. Please help, no F250 should be creeping along on the shoulder as chevies whiz by! I'm spending a fortune replacing burned air filters, too.
Reply With Quote
  #2  
Old 12-07-2000, 05:20 AM
hotrodford_88 hotrodford_88 is offline
Posting Guru
 
Join Date: Aug 2000
Location: Texas
Posts: 1,474
hotrodford_88 is starting off with a positive reputation.
72 360 backfires thru carb

Have you by any chance checked your timing? Then again it could be something else. Fords are finicky after all. But then aren't we all?


[link:www.geocities.com/hotrodford_88/|Hotrodford_88's Webpage]

[link:www.geocities.com/westlake_vfd/Westlake.html|Westlake VFD Website]


__________________
1965 F-100, 390, Edelbrock Performer RPM, Holley 600, Pertronix ignition, Edelbrock Performer Cam, K&N Air Filter, Flowmaster 2 chamber mufflers, Heddman Headers, A/C, Lokar transmission mounted shift
Reply With Quote
  #3  
Old 12-07-2000, 07:15 AM
jowilker's Avatar
jowilker jowilker is offline
Post Fiend
 
Join Date: Jun 1999
Location: Creedmoor, North Carolina
Posts: 22,885
jowilker is a splendid one to beholdjowilker is a splendid one to beholdjowilker is a splendid one to beholdjowilker is a splendid one to beholdjowilker is a splendid one to beholdjowilker is a splendid one to behold
https://www.facebook.com/?ref=tn_tnmn jowilker
72 360 backfires thru carb

Joe, I think just maybe you posted your answer with the new wires. Sounds a little likely to me that you have a couple of wires crossed.


John
jowilker

66 F100s
In the still cool hours of the night, you can hear chevys rusting away.
__________________
In the cool still quiet hours of night, you can hear chevies rusting away.
Reply With Quote
  #4  
Old 12-07-2000, 10:08 AM
dzjammer dzjammer is offline
Senior User
 
Join Date: Dec 2000
Location: Nebraska Farm
Posts: 435
dzjammer is starting off with a positive reputation.
72 360 backfires thru carb

I had the same problem this summer, I chased it through the carb and timing before settling on another set of new wires. After pulling the wires off, I checked the resistance through each one. One of them was bad, after closer inspection, the end that goes into the distributor was charred and not making good contact. Even though my wires were only 4 months old, something burned the conductor off the end. Be sure to check all your wires and nothing is cross-firing.


Dave,
79 F-150 4X4, 390 w/C6, Edelbrock carb, 33X12.50 never will be finished
__________________
Dave,
1979 F150 4x4 390 w/C6, Edelbrock carb, cam, intake.
2000 F250 PSD, Kwik filter, AIH delete, DIY fuel pickup. Superchip, WW
1994 Explorer EB, with a twin still awaiting repair
Reply With Quote
  #5  
Old 12-09-2000, 08:16 PM
cranium_slayer cranium_slayer is offline
New User
 
Join Date: Jul 2000
Posts: 7
cranium_slayer is starting off with a positive reputation.
72 360 backfires thru carb

HI! you failed to say if your truck has point ignition. the year of the truck says it has.i would be in stalling a new set plus a new condenser/ if the points are set with too wide a gap, it will cause backfiring through the carb. hope this helps. good luck.
Reply With Quote
  #6  
Old 12-11-2000, 12:24 AM
fomojo fomojo is offline
New User
 
Join Date: Dec 2000
Posts: 2
fomojo is starting off with a positive reputation.
72 360 backfires thru carb

thank you all for the tips. Despite the many suggestions, my mighty F250 continues to backfire through the carb if I try to maintain 60mph up hills for more than a few minutes. I can keep up with traffic on grades for a thrilling few minutes, though. I've checked the timing and made sure all plug wires are going to the proper plugs. Some wires cross to achieve correct routing. I routed #7 and #8 wires as far apart as practical. Wires are only 1 week and one test drive old and look OK on an ohm meter. Previous owner replaced points with white "igniter" pickup. This unit has no visible air gap between itself and green tape-like material on the distributor shaft, but shows no sign of rubbing. Is it properly installed? Could my truck be rejecting this non-Ford gizmo? A friend suggested I look at the carb's power-jet diaphragm. I did. It's fine. I have heard that the resistor wire from the ignition switch can break down and cause backfiring through carb. Does the '72 Camper Special XLT with automatic have the resistor wire?
Reply With Quote
  #7  
Old 12-11-2000, 06:43 AM
jowilker's Avatar
jowilker jowilker is offline
Post Fiend
 
Join Date: Jun 1999
Location: Creedmoor, North Carolina
Posts: 22,885
jowilker is a splendid one to beholdjowilker is a splendid one to beholdjowilker is a splendid one to beholdjowilker is a splendid one to beholdjowilker is a splendid one to beholdjowilker is a splendid one to behold
https://www.facebook.com/?ref=tn_tnmn jowilker
72 360 backfires thru carb

Joe your timing chain could be slipped or streatched. I have thought it was in the timing somehow. It is hard to deceifer from behind a computer screen. :-)


John
jowilker

66 F100s
In the still cool hours of the night, you can hear chevys rusting away.
__________________
In the cool still quiet hours of night, you can hear chevies rusting away.
Reply With Quote
  #8  
Old 12-12-2000, 11:22 PM
HiMe HiMe is offline
Senior User
 
Join Date: Jan 2000
Posts: 166
HiMe is starting off with a positive reputation.
72 360 backfires thru carb

Reply With Quote
  #9  
Old 03-03-2011, 03:18 PM
'74390's Avatar
'74390 '74390 is offline
Freshman User
 
Join Date: May 2010
Location: Jacksonville
Posts: 36
'74390 is starting off with a positive reputation.
you may need to check for a burned valve, that is the problem with my 390
Reply With Quote
  #10  
Old 03-03-2011, 07:38 PM
ted_the_undead ted_the_undead is offline
New User
 
Join Date: Mar 2011
Posts: 1
ted_the_undead is starting off with a positive reputation.
Have you done a vacuum test, or put a vacuum gauge on the old girl? I'm wondering if your advance is working right, might be something to check, pretty easy to pull the line and plug it off to test. Especially if it was one of those dual diaphragm gizmos that advanced on decel too (if OEM), might not be getting the timing it wants or needs, especially under heavy load.
Reply With Quote
  #11  
Old 04-04-2011, 03:32 PM
'74390's Avatar
'74390 '74390 is offline
Freshman User
 
Join Date: May 2010
Location: Jacksonville
Posts: 36
'74390 is starting off with a positive reputation.
try spending as little money as possible before looking at the heads. if no valves are burned, it would only cost 35 to put everything back together.
Reply With Quote
  #12  
Old 04-05-2011, 08:15 PM
312 312 is offline
Elder User
 
Join Date: Feb 2004
Posts: 990
312 is starting off with a positive reputation.
does it idle smooth.backfiring is caused by cracked dist,cap,crossed wires,pushrod off,head gasket blown between cylinders,out of time,bent intake valve.
Reply With Quote
  #13  
Old 04-05-2011, 08:49 PM
sandmanf250 sandmanf250 is offline
Posting Guru
 
Join Date: Mar 2003
Posts: 1,246
sandmanf250 is gaining momentum as a positive member of FTE.
backfiring at 60

maybe you have to richen the mainjet.
Reply With Quote
  #14  
Old 04-12-2011, 08:55 AM
TheHarrWay's Avatar
TheHarrWay TheHarrWay is offline
Junior User
 
Join Date: Feb 2011
Location: Lilburn, GA
Posts: 70
TheHarrWay is starting off with a positive reputation.
OK, before anyone jumps to club me just listen.. i know it may sound stupid, but check your voltage( battery/alternator).. my alternator is putting out VERY low voltage, but since im broke as crap right now i just stick it on a charger every 2-4 days. About 2 weeks ago i was trying to make it home as it was dying and for about 3-4 minutes before pulling in the driveway it was back firing like crazy. but only under hard throttle.. I doubt this is your problem, but always good to eliminate easy things first. do you still have your old wires? i would put them back on and see if the problem goes away. if so get another set of wires..
__________________
USMC, Ret.
OIF 06-07
'71 F100,360,4spd "Red"

Horsepower is how fast you hit the wall,
Torque is how far you take the wall with you.....
Reply With Quote
  #15  
Old 04-13-2011, 11:15 PM
orich's Avatar
orich orich is offline
Postmaster
 
Join Date: Aug 2003
Location: San Jose ca.
Posts: 3,226
orich is gaining momentum as a positive member of FTE.orich is gaining momentum as a positive member of FTE.
Hmm yup sounds like over heated exh seats causes by unleaded gas. If the head have never been converted to run the unleaded gas. Or Very common problem. The unleaded additives does help. But it will not correct a burned seat or valve. But if you using the lowest octane gas this adds to the problem.
Burning seats start out on a heavy pull like your doing up a hill or with a camper on it trying to pass another vehicle and it take a nose-dive popping back out the carb. Also could be a combo of intake gasket bad and burned valves & seats.. Do a compression test first. Then no more guessing games. ...
orich..
__________________
1971 F250 4wd Nv4500-5spd O/D 416cid owned since 1978. Toured Vietnam 1968-70 15 months 512th Trans Co. Driver of the Iron Butterfly Gun truck http://www.youtube.com/watch?v=5H7U71KZEJw
http://www.youtube.com/watch?v=Lemll...r_embedded#t=0 & http://www.youtube.com/watch?v=119sc1w8J2Y#t=2
Reply With Quote
Old 04-13-2011, 11:15 PM
 
 
 
Reply

Similar Threads
Thread Thread Starter Forum Replies Last Post
having starting problem when hot 72 F150 W/360 jdsunset 1967 - 1972 F-100 & Larger F-Series Trucks 4 05-17-2012 08:51 PM
my ford f100 360, is backfiring through the carb dukes18 FE & FT Big Block V8 (332, 352, 360, 390, 406, 410, 427, 428) 12 02-02-2011 09:58 PM
Edelbrock 1406 missing at part choke Reptar360 Fuel Injection, Carburetion & Fuel System 2 03-22-2005 10:07 PM
Accelaration problem with Carb? vandelayind 1967 - 1972 F-100 & Larger F-Series Trucks 8 10-20-2004 10:08 AM
'72 F250 w/ a 360 clampett FE & FT Big Block V8 (332, 352, 360, 390, 406, 410, 427, 428) 5 04-12-2004 02:46 AM


Go Back   Ford Truck Enthusiasts Forums > Older, Classic & Antique Trucks > 1967 - 1972 F-100 & Larger F-Series Trucks

Tags
360, backfires, backfiring, carb, crossed, engine, f250, ford, gap, ignition, plug, point, points, setting, timing, wire

Thread Tools Search this Thread
Search this Thread:

Advanced Search

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 On
Trackbacks are On
Pingbacks are On
Refbacks are On

Forum Jump


Participate In The Forums

Create new posts and participate in discussions. It's free!

Sign Up »





All times are GMT -5. The time now is 08:57 PM.


Powered by vBulletin® Version 3.8.7 AC1
Copyright ©2000 - 2014, Jelsoft Enterprises Ltd.
Advertising - Terms of Use - Privacy Statement - Jobs
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. Ford® is a registered trademark of the Ford Motor Company.

vbulletin Admin Backup