Backfiring
Junior User
Joined: Dec 2001
Posts: 84
Likes: 0
From: Burnaby BC, Canada
Backfiring
Is there any other reason besides timing that would cause my truck to backfire? It's a 390/c6 combo in a '72 Camper special. Once the truck is warm, if I put my foot into it to go up a hill or accelerate past someone, it gives a couple violent backfires before deciding to get moving. I have the timing set at the timing mark that it was set on when I purchased the truck a couple months ago. I believe it is at 6 degrees btdc. Any help would be appreciated, I don't know if it matters but the temperature here has been just above the freezing mark but I let the truck run with the manual choke for 10-15 minutes before attempting to go anywhere. I only use it to go to and from work mainly which is only 4-5 miles each way. I do take it out for a good run on the freeway once a week or so just to clean things out.
Thanks in advance,
Don W.
Thanks in advance,
Don W.
New User
Joined: Jan 2008
Posts: 0
Likes: 24
Backfiring
Crossfiring inside the distributor cap caused by:
Cracked Cap,Worn distributor shaft.
Dennis https://www.ford-trucks.com/user_gallery/sizeimage.php?&photoid=1733&.jpg
Please Don't Ask Me Any Tough Questions As:
"I'm Saving My Memory For When I Develop Alzheimer's"
78 F-150 429CJ,Silver
w/Explorer Pkge.
641/2-Mustang 260,Pre-World's Fair Car.
64-Fairlane500 S/C waiting for a 390-4spd.
68-Mustang 289-Sunlit Gold 80,892Mi
78-Buick LeSabre 403 4V
84 Volvo DL Wagon
Cracked Cap,Worn distributor shaft.
Dennis https://www.ford-trucks.com/user_gallery/sizeimage.php?&photoid=1733&.jpg
Please Don't Ask Me Any Tough Questions As:
"I'm Saving My Memory For When I Develop Alzheimer's"
78 F-150 429CJ,Silver
w/Explorer Pkge.
641/2-Mustang 260,Pre-World's Fair Car.
64-Fairlane500 S/C waiting for a 390-4spd.
68-Mustang 289-Sunlit Gold 80,892Mi
78-Buick LeSabre 403 4V
84 Volvo DL Wagon
New User
Joined: Jan 2008
Posts: 0
Likes: 24
Backfiring
Yep !
I forgot to mention that Moisture in the Cap can play part of BF too.
Dennis https://www.ford-trucks.com/user_gallery/sizeimage.php?&photoid=1733&.jpg
Please Don't Ask Me Any Tough Questions As:
"I'm Saving My Memory For When I Develop Alzheimer's"
78 F-150 429CJ,Silver
w/Explorer Pkge.
641/2-Mustang 260,Pre-World's Fair Car.
64-Fairlane500 S/C waiting for a 390-4spd.
68-Mustang 289-Sunlit Gold 80,892Mi
78-Buick LeSabre 403 4V
84 Volvo DL Wagon
I forgot to mention that Moisture in the Cap can play part of BF too.
Dennis https://www.ford-trucks.com/user_gallery/sizeimage.php?&photoid=1733&.jpg
Please Don't Ask Me Any Tough Questions As:
"I'm Saving My Memory For When I Develop Alzheimer's"
78 F-150 429CJ,Silver
w/Explorer Pkge.
641/2-Mustang 260,Pre-World's Fair Car.
64-Fairlane500 S/C waiting for a 390-4spd.
68-Mustang 289-Sunlit Gold 80,892Mi
78-Buick LeSabre 403 4V
84 Volvo DL Wagon
Elder User
Joined: Nov 1999
Posts: 733
Likes: 0
Backfiring
Hopefully your problem lies in the ignition.But,Sounds to me like exhaust valve float.I had a truck that did that under load and it had alot of mils on it.I put new springs in it and it quit.Another case:I have a truck that i leave sit for long periods,when i first start it it backfires and pops,then will quit after 1/2 hour of running.That is a valve hanging up or i call a lazy spring,or carbon stuck on the seat.
