My 1986 Toyota Pickup is back firing I need help

Rebel4x4Crazy

Member
Joined
Jan 19, 2013
Location
Gastonia
Hey everybody I have a 1986 Toyota and it is back firing. Let me go through what I have done, First about a week ago I rebuilt my motor, I have put a new crank and bearings and new 20 over pistons new rods and a new preformance head on it and a new preformance cam. The block has also been bored homed and mechined and cleaned by a professional and it has a new water and oil pump to. So I start putting it back together and it goes back easy well i set the timing to 0 and tried to tune the carb alittle. Well the carb was pulling good vaccume so i decided to run it and when I change gears it back fires and shoots a 6 inch flame out of the tail pipe and when i crank it it shoots out black smoke. it does have a little exhaust leak . So can anybody help me please
 
Were there any instructions/specs for the timing w the new cam? have you put a timing light on it? did you install a new timing chain w new gears and chain guides/tensioner? Was the timing chain cover worn much where the oil pump rotates against it? Did the new head come w new valves, rockers and shafts etc.? Are all the vacuum lines hooked up correctly? did you follow any break in procedure once you got it running.............It sounds like the timing is advanced or retarded too much but I'm no expert.
 
The timing is set by the intructions and it has a new chain, gears and tensioner. I did check it with a timing light and it is set to 0 on the top of the harmonic balancer and it does have a new timing cover. and yes it was the full head kit so yes it came with new valves, rockers and shafts, bearing etc. Yes i did follow the break in steps i did add zinc and I have not dowged it any i have babied the hell out of it and the timing advance is correct by oem standards and all of my vaccum lines are hooked up correct. Now the problem i know i do have is the exhaust has a little leak. Now the catalytic converter has been gutted and I have a glass pack instead of the original muffler could that be a problem
 
it run like shit before i rebuilt it and the muffler was gone when i rebuilt it i leaned the carb because it was burning way to rich now its burning right its just back firing and yes its the orginal 81-84 carb my motor is an 81-84 22r but the carb has been rebuilt
 
It runs amazing it just back fires this one mechanic i talked to said it might be after burn and thats where gas fumes is buiding up in the exhaust because there is no back presser and the exhaust leak is letting it ignight but i dont know i have never had this problem this is the first toyota ive owned
 
You need to fix your exhaust stuff first. If too much cold air gets sucked into the exhaust valves, you will ruin your new valves. Fix the exhaust leak and put some kind of muffler on it. Loud exhaust sucks.
 
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