backfiring out of the valve cover when trying to crank
Thread Starter
Launching!
Joined: Mar 2012
Posts: 251
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backfiring out of the valve cover when trying to crank as the title says, I am having a issue where every time i try to crank my car it is backfiring threw the valve covers and blowing out the gaskets .a white burnt smelling smoke comes out any ideas ?
What prompted you to change the computer? How long did the car sit for and whats the mileage of the motor?
Did you try checking things out prior to starting the car? fresh oil,good gas,spark plugs etc.The white smoke burnt smell could be alot of things fuel or spark/timing related.Could be bad timing chain too..who knows..would it start at all or just cranking it backfires that badly.Must sound awful!
Did you try checking things out prior to starting the car? fresh oil,good gas,spark plugs etc.The white smoke burnt smell could be alot of things fuel or spark/timing related.Could be bad timing chain too..who knows..would it start at all or just cranking it backfires that badly.Must sound awful!
timing is way off.
Or you have valves stuck open, maybe a snapped timing chain.
Have had first had experience with this situation myself. When an engine is backfiring out the intake or into the valve covers it is because the valve or ignition timing is way off. Ignition timing is controlled by the ecu with inputs from the crank and/or the cam sensor so unless both those sensors are bad i dont see it being the ignition timing. Check for any crank or cam sensor codes. If none pull a valve cover and crank the engine to make sure the valves are opening and closing.
Or you have valves stuck open, maybe a snapped timing chain.
Have had first had experience with this situation myself. When an engine is backfiring out the intake or into the valve covers it is because the valve or ignition timing is way off. Ignition timing is controlled by the ecu with inputs from the crank and/or the cam sensor so unless both those sensors are bad i dont see it being the ignition timing. Check for any crank or cam sensor codes. If none pull a valve cover and crank the engine to make sure the valves are opening and closing.
Thread Starter
Launching!
Joined: Mar 2012
Posts: 251
Likes: 0
75-80k has been driven hard
i have been working on it slowly for some time now. ive replaced most the sensors because of codes it was throwing, im having a spark issues is why i got the new computer to make sure that wasn't the problem also have changed the crank angle sensor.
all started when i was driving the car one night, it started to bog down if i was not pushing on the gas. so i pulled over, being new oil at night i couldn't see any on the stick so i added more., ended up being 2 quarts over at this point
so it started smoking pretty bad and would die if i let my foot of the gas,
so quickly went towards home almost there i heard a clanking sound 3 times and the car just shut off light and everything.
turned out the starter had broken off
i moved up north for a few years and now im back and trying to get it running again
i have been working on it slowly for some time now. ive replaced most the sensors because of codes it was throwing, im having a spark issues is why i got the new computer to make sure that wasn't the problem also have changed the crank angle sensor.
all started when i was driving the car one night, it started to bog down if i was not pushing on the gas. so i pulled over, being new oil at night i couldn't see any on the stick so i added more., ended up being 2 quarts over at this point
so it started smoking pretty bad and would die if i let my foot of the gas,
so quickly went towards home almost there i heard a clanking sound 3 times and the car just shut off light and everything.
turned out the starter had broken off
i moved up north for a few years and now im back and trying to get it running again
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were talking about an LS1 right? and theres no codes in the computer? even if the ses light isnt on scan it for codes and pending codes. Otherwise is sounds like valve timing is off. could have jumped a tooth cause of a worn chain. Ive had a new chain snap on me on first startup.
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Verdad Gallardo I really think you got a mechanical timing issues also..mainly the chain.But if you dont want to tear right down into that yet.You have to atleast remove the valve covers,disconnect the ecu and crank it over.make sure all the valves etc are functioning.And check everything else mentioned earlier.Are you getting good oil pressure during crank?
If you end up having to replace the chain..good time for some small upgrades..oil pump..cam etc.
If you end up having to replace the chain..good time for some small upgrades..oil pump..cam etc.
Here is what i would do first. I would pull the front cover and try and line up the timing marks on the cam gear. Do that first, this will tell you if your valve timing is off or not.
Hold off on the cam choice questions till you got a better handle of what the hear of the issue is and extent of damage.If the chain has jumped or broke then it might be awhile before you have the car running again.Pistons could hit valves,bent pushrods etc
Once you find out whats wrong then its easier to suggest the best route on replacing parts and upgrades at the sametime while its apart.Full cam kit,springs,new pushrods,timing chain,lifters/trays,oil pump wouldnt be a bad idea depending on what you goals of the car is.
Once you find out whats wrong then its easier to suggest the best route on replacing parts and upgrades at the sametime while its apart.Full cam kit,springs,new pushrods,timing chain,lifters/trays,oil pump wouldnt be a bad idea depending on what you goals of the car is.
Hold off on the cam choice questions till you got a better handle of what the hear of the issue is and extent of damage.If the chain has jumped or broke then it might be awhile before you have the car running again.Pistons could hit valves,bent pushrods etc
Once you find out whats wrong then its easier to suggest the best route on replacing parts and upgrades at the sametime while its apart.Full cam kit,springs,new pushrods,timing chain,lifters/trays,oil pump wouldnt be a bad idea depending on what you goals of the car is.
Once you find out whats wrong then its easier to suggest the best route on replacing parts and upgrades at the sametime while its apart.Full cam kit,springs,new pushrods,timing chain,lifters/trays,oil pump wouldnt be a bad idea depending on what you goals of the car is.
If you did have valves hit pistons then you will most likely have bent valves and broken/bent pushrods. When this happened to me it was cheaper to buy another set of heads, than to try and repair mine. I bought a set of heads for $50 and replaced the few pushrods i bent and i was good to go.
Let us know what you find, im interested to find out whats going on.
Thread Starter
Launching!
Joined: Mar 2012
Posts: 251
Likes: 0
i guess ill start taking it apart as i have free time, an i will report back with findings. should i go ahead and order a oil pump and gaskets ?
and what would be the best way to keep moister out of the motor as i will not be able to complete this in 1 day
and what would be the best way to keep moister out of the motor as i will not be able to complete this in 1 day
I wouldnt order anything yet. If youre concerned with moisture just stuff it with paper towels or rags.
TECH Enthusiast
Joined: Feb 2007
Posts: 625
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From: Raleigh, NC
Out the VALVE COVER? Engines don't backfire out the valve cover. If it's blowing out a valve cover seal, the cylinder head has a hole in it from the combustion chamber to the top of the head, and it's junk.
Or is it the backfiring through the intake or exhaust?
Or is it the backfiring through the intake or exhaust?