issue 1: back fires?

[Dicipleofthelie]

after i put a new motor in my car....it back fires like a whore when im decelerating.....1st 2nd mostly....usually when i use the engine to slow the car as aposed to the brakes...any sugestions?

[Neon]

how does back fire feels like ?????? lol

[Dicipleofthelie]

just a pop

kinda loud pop...i always can tell when it happens

[bmw5002]

mainly could mean 3 things, either 1:
there is a leak in the exhaust system somewhere and air is getting in.

2:
is that motor carbeurated or fuel injected? if its fuel injected it shouldn't be happening without the computer throwing an error. but since youve got an 86, i doubt it would have a computer and its probly carbed. if u got a carb, that means that the motor is running lean on deceleration. it doesnt always fire and the un-burnt gases go through the exhaust, then when it does fire it ignites the unburnt gases in the exhaust and backfires. the idle/pilot jet needs adjusting. if ur into do-it-yourself learn about how to adjust it. you need to go to a bigger pilot jet to let more fuel in when idling and decelerating.

3:
a timing issue

[micro214_kp61]

it's not tuned properly!

[rolla-XRS]

LAst car I had that backfired was this 1984 pos Dodge Omni. IT would backfired whenever water got into the distributor cap since

I guess this was causing fuel to enter into the cylinder and not burn at the appropriate timing. BAM!!

[Dicipleofthelie]

hmm....the running lean thing is the most probable culprit

due to the fact that about a year ago i replaced the carb.....but didnt have the sense (at that time) to go get it professionaly adjusted.


and its had a recent tune up...as in like..a week ago....so its not a tuning issue