Truck backfires and doesn’t start
- Thread starter joeybtl
- Start date
Disclaimer: Links on this page pointing to Amazon, eBay and other sites may include affiliate code. If you click them and make a purchase, we may earn a small commission.
Grit dog
Full Access Member
- Joined
- May 18, 2020
- Posts
- 6,907
- Reaction score
- 12,111
- Location
- Auburn, Washington
- First Name
- Todd
- Truck Year
- 1986, 1977
- Truck Model
- K20, C10
- Engine Size
- 454, 350
You’re going to have to throw out a few more bread crumbs than that…
joeybtl
Junior Member
- Joined
- Oct 14, 2023
- Posts
- 12
- Reaction score
- 0
- Location
- arkansas
- First Name
- Joey
- Truck Year
- 1984
- Truck Model
- c10
- Engine Size
- 305
I don’t really know what else to say it just spits gas through the mouth of the carb up about 3ft and if I adjust the timing either way it still does the same thing if you want a video text me at 501-743-0653
AuroraGirl
Full Access Member
- Joined
- Sep 8, 2019
- Posts
- 9,693
- Reaction score
- 6,862
- Location
- Northern Wisconsin
- First Name
- Taylor
- Truck Year
- 1978, 1980
- Truck Model
- K10, K25
- Engine Size
- 400(?), 350
stop touching your timing!!
The first and most obvious thing to check is you have the wires on wrong or your mechanical advance is stuck out.
Confirm thats fine before anything else
fast 99
Full Access Member
- Joined
- Dec 31, 2021
- Posts
- 1,992
- Reaction score
- 2,856
- Location
- Spokane, Washington
- First Name
- Brian
- Truck Year
- 81,85
- Truck Model
- K20
- Engine Size
- 350
What preceded this issue? Ran fine one day. Shut it off and now no restart or something else.
joeybtl
Junior Member
- Joined
- Oct 14, 2023
- Posts
- 12
- Reaction score
- 0
- Location
- arkansas
- First Name
- Joey
- Truck Year
- 1984
- Truck Model
- c10
- Engine Size
- 305
No it’s been a project truck for abt a year and one day it ran for about 20 seconds and then shut off and now it backfires and won’t start got a new carb. Still nothing works
Rickf
Full Access Member
- Joined
- Jul 29, 2017
- Posts
- 567
- Reaction score
- 708
- Location
- Grafton NH
- First Name
- Rick
- Truck Year
- 1974, 1954 & a 1937
- Truck Model
- K20
- Engine Size
- 350
Did it run ok before you did anything to it? Did you do any valve adjustment?, Have or can you do a compression and/or leak down tests? Correct firing order? Do you have a service manual with a trouble shooting section?
joeybtl
Junior Member
- Joined
- Oct 14, 2023
- Posts
- 12
- Reaction score
- 0
- Location
- arkansas
- First Name
- Joey
- Truck Year
- 1984
- Truck Model
- c10
- Engine Size
- 305
No it was in a garage in Texas and didn’t run when I got it. I’ve searched for leaks can’t find any and I’ve tweaked the valves but same thing each time. And there is no manual that I have. I’m 16 and trying to get a job to fix it up been trying for a while it’s just been a process.
- Joined
- Oct 31, 2020
- Posts
- 327
- Reaction score
- 718
- Location
- Easley sc
- First Name
- Jeff
- Truck Year
- 1985
- Truck Model
- K10
- Engine Size
- 350
Pull your distributor cap , see if the rotor is spinning or not . Intermittently or a constant rotation . I've seen the distributor gears wear out and jump a tooth here and there sparking out of time . Or you can grab rotor button and see if it will turn . It shouldn't. Pull the ignition wire first so you get zero spark if you have gas fumes though !
fast 99
Full Access Member
- Joined
- Dec 31, 2021
- Posts
- 1,992
- Reaction score
- 2,856
- Location
- Spokane, Washington
- First Name
- Brian
- Truck Year
- 81,85
- Truck Model
- K20
- Engine Size
- 350
Disable the ignition and crank with the starter, does it sound even.? If a cylinder isn't filling properly when the engine rotates a bad cylinder the starter will increase in speed. Kind of a quick and dirty compression test. If uneven the diagnostic procedure takes a different turn.
Grit dog
Full Access Member
- Joined
- May 18, 2020
- Posts
- 6,907
- Reaction score
- 12,111
- Location
- Auburn, Washington
- First Name
- Todd
- Truck Year
- 1986, 1977
- Truck Model
- K20, C10
- Engine Size
- 454, 350
Is it still a 305 with all the electronics hooked up? There are some 80s 305 experts on here. They’re a bit different animal.
Until then , unknown engine, presuming.
Compression check. Firing order of plug wires. Base timing check.
Those are the few things I’d look at first. Good luck bud
Until then , unknown engine, presuming.
Compression check. Firing order of plug wires. Base timing check.
Those are the few things I’d look at first. Good luck bud
