lt1 wont start but backfires
Thread Starter
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Joined: Sep 2009
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lt1 wont start but backfires i have 1995 pontiac trans am with a 355,well i recently had my motor rebuilt and i put it back in and hooked everything backu.went to start and it just backfired and didnt star.well i looked at some forums on here and all seemed to be leaning toward it being having the opti on.so i pulled it off and sure enough we did.so i put that back on correctly and then realized i had 2 cut injector wires so i also replaced those.and went back to start again and now the backfie has gotten a little less worse.but it backfires everytime you hold the throttle down and it just randomly pops and its smoking out of the heads.if anyone can help please do
On The Tree
Joined: Nov 2008
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i have 1995 pontiac trans am with a 355,well i recently had my motor rebuilt and i put it back in and hooked everything backu.went to start and it just backfired and didnt star.well i looked at some forums on here and all seemed to be leaning toward it being having the opti on.so i pulled it off and sure enough we did.so i put that back on correctly and then realized i had 2 cut injector wires so i also replaced those.and went back to start again and now the backfie has gotten a little less worse.but it backfires everytime you hold the throttle down and it just randomly pops and its smoking out of the heads.if anyone can help please do
Thread Starter
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Joined: Sep 2009
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how to check your coil
- pull your coil wire off of the top of the opti and leave the other end attqached to your coil and then put a spark plug on the end that is removed and then lay the plug on a ground (header/ anything close that can be used as a ground) then crank it and see if the spark is consistant or irradic.. of course there will be some kind of spark because your car does still run
i honestly dont think this is a coil problem
sounds like a timing issue or firing order ussue
- pull your coil wire off of the top of the opti and leave the other end attqached to your coil and then put a spark plug on the end that is removed and then lay the plug on a ground (header/ anything close that can be used as a ground) then crank it and see if the spark is consistant or irradic.. of course there will be some kind of spark because your car does still run
i honestly dont think this is a coil problem
sounds like a timing issue or firing order ussue
sounds like a timing issue whether it be valvetrain or ignition idk.
was the cam installed properlly with the dot-to-dot method? is the valve lash correct? are all the plug wires on the opti correct? is the opti installed correctly?
was the cam installed properlly with the dot-to-dot method? is the valve lash correct? are all the plug wires on the opti correct? is the opti installed correctly?
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Thread Starter
Registered User
Joined: Sep 2009
Posts: 12
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how to check your coil
- pull your coil wire off of the top of the opti and leave the other end attqached to your coil and then put a spark plug on the end that is removed and then lay the plug on a ground (header/ anything close that can be used as a ground) then crank it and see if the spark is consistant or irradic.. of course there will be some kind of spark because your car does still run
i honestly dont think this is a coil problem
sounds like a timing issue or firing order ussue
- pull your coil wire off of the top of the opti and leave the other end attqached to your coil and then put a spark plug on the end that is removed and then lay the plug on a ground (header/ anything close that can be used as a ground) then crank it and see if the spark is consistant or irradic.. of course there will be some kind of spark because your car does still run
i honestly dont think this is a coil problem
sounds like a timing issue or firing order ussue
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Brett Foote Thread Starter
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the opti was on incorrectly but we fixed that after looking up the correct way to install.and im not sur eabout the cam the guys at the machine shop put the cam and timing chain on,and we are not certain how to do the valve lash we looked for hours on the internet and tried the one that sounded best but their is no key on the hub to mark top dead center
