devic

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 ?

fastassls1maro

iTrader: (22)

was anything done to it recently before this started happening(tune up, cam install.......)??

devic

the car had been setting for some time, i just changed out the computer, but it was doing this before that

Redbull87

iTrader: (3)

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!

bp m1009

iTrader: (2)

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.

devic

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

devic

the car seems like it wants to start but cant, some times i can get it to run for like 2 - 3 seconds and rpm slows and dies only reaching a few hundred rpm's

bp m1009

iTrader: (2)

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.

Redbull87

iTrader: (3)

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.

devic

yes it a ls1... and damn this sucks, how hard would you rate fixing this issue ?

bp m1009

iTrader: (2)

well i mean it depends whats actually wrong. If it jut needs a new chain, then its not a big deal just pull the front cover, drop the oil pan, remove the oil pump and put the new chain on. But if something like this did happen id be concerned with the valves having hit the pistons. Because this is an interference engine.

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.

devic

if it did slip a tooth or the chain broke what am i looking at as far as possible damage ?

devic

also what cam choices should i look at if this is the case, i would be looking for a good street cam for DD

Redbull87

iTrader: (3)

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.

bp m1009

iTrader: (2)

I agree, find out whats going on first.
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.

devic

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

bp m1009

iTrader: (2)

I wouldnt order anything yet. If youre concerned with moisture just stuff it with paper towels or rags.

usdmholden

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?

devic

any advice for getting the crank pulley bolt off ?

bp m1009

iTrader: (2)

Mine came off easy with an impact gun. Otherwise you can put it in gear and put e brake on and use a bigratchet probly with a cheater bar.