Back Firing HELP!!!

GrandWaggoner757

i have 1990 grand waggoner and 2 days ago the spark plug wares got melted on my headers so i replaced the wires and spark plugs and my firing order is rite and it back fires now?

ironman_gq

by backfire do you mean it pops out of the carb or that it pops out of the tailpipe which isnt a backfire but unburned fuel igniting in the pipe and making a loud bang. if its in the pipe check your choke and then make sure your plugs and wires have good connections and are in the right order.

GrandWaggoner757

it pops out the tail pipes and out the carb and i got the firing rite and good connection i have some people saying its ethere my carb or i bent a valve

dwg86

Put #1 cylinder on TDC. Make sure the rotor is pointing at #1 then check firing order from there...1-8-6-4-5-3-7-2...I think?

tufcj

1-8-4-3-6-5-7-2 It's really easy to get 5-7 switched. Count is clockwise around the cap. How many miles? Could have a bad timing chain and jumped a tooth. Could also be the dreaded distributor drive gear wear. Bob tufcj

ironman_gq

crossfiring? maybe a tracked up cap or crud under the cap causing it to fire to two cylinders at once. I had one with a bad timing set backfire under heavy load and one with the timing way off do the same thing.

dwg86

tufcj wrote
1-8-4-3-6-5-7-2

It's really easy to get 5-7 switched. Count is clockwise around the cap.

How many miles? Could have a bad timing chain and jumped a tooth. Could also be the dreaded distributor drive gear wear.

Bob
tufcj

Thats the right firing order! Sorry , I had a brain fart.

mkzmomo

tufcj wrote
1-8-4-3-6-5-7-2

It's really easy to get 5-7 switched. Count is clockwise around the cap.

How many miles? Could have a bad timing chain and jumped a tooth. Could also be the dreaded distributor drive gear wear.

Bob
tufcj

that's what happened to me once #-o

mrtazwrench

mkzmomo wrote
tufcj wrote
1-8-4-3-6-5-7-2

It's really easy to get 5-7 switched. Count is clockwise around the cap.

How many miles? Could have a bad timing chain and jumped a tooth. Could also be the dreaded distributor drive gear wear.

Bob
tufcj

that's what happened to me once #-o

I can rattle that off the top of my head anytime, most V8's use that with the eception of ford since they number their cylenders different.