My old man has a 96 Seville SLS that has been sitting up for around 6-8 months. Before he parked it, it was saying battery has no charge, so obviously a connection problem somewhere, more than likely the alternator.. Anyway, he parked it because the starter locked up, and as you cadi fans know, it's located underneath the intake.. He wasn't really worried with it up until he had a stroke and the taurus blew a head gasket, so we decided to change out the starter, took everthing apart necessary, etc etc.. Put it all back together, jumped it off, and it's just shooting out clouds of smoke, sounds like it's misfiring, but there's no way the plugs can be crossed, I marked them and they even have markings on their own, anyway. It was knocking real bad when we started it up (took into consideration at how long it had been setting up) but it seems as though after running for roughly 30 minutes that it seems to have almost no compression to stay running, when given gas, it just blows out clouds of smoke like I said.. I don't know how a head gasket could be blown from just sitting up but maybe they've had time to harden? anyway, everything went back together real nice, it's just the knocking/smoke/low compression.. It sounds really weak whereas when he parked it, it was running really well, like it had no problems at all.. It has the 4.6 as you all may already know.

 

I would start with the simple things first.
Did the SES light come on while running?
Did it log any DTC's?
Did you drain the fuel tank and add fresh gas and change fuel filter? Certain 'blends' of
fuel go bad over time. Does the fuel smell like 'gas' or does it smell more like turpintine?
You say you 'jumped' the car to start it, but did you fully charge the battery first?
A weak battery in computer controlled vehicles can cause all sorts of problems.

Although the Northstar engines have a bad reputation for headgasket failures it is usually
caused by poor cooling system maintenance or overheating, not from sitting.

These are just a few simple suggestions, there are some good Techs on here that may offer
you some more detailed advice.

 

hey man, preciate the reply.. no ses light came on, no error codes, except no battery charge.. which is something i forgot to mention.. only thing it says is to change oil and no battery charge.. so the alt is probably bad/or a bad wire to the alt.. more than likely the alt though. didn't drain the fuel or change filter.. and it does smell like pure gas.. we charged the battery.. tested good.. drove the car around the block a few times and the smoking and rough idle quit.. now it's jus the charging problem haha. always something isn't it. least the old girl is running like before though. so i'm sure if i change the alt or fix whatever it is, it will probably run 10x better.. really appreciate ya.

 

Just something to check, the PCV valve is one thing you want to check, it could be sucking oil into the system, also i would clean the throttle body and check the fuel pressure regulator.

Pull your spark pulgs one at a time and see if oil is on the plug. Then go from there.