Symtons of coil pak or car wont start after warming up

see if you have spark from coil pak if not spark coil pak gone replace coil pak

you didnt change them 1 by 1, did you. oops...
see the FSM for this, by engine type
or alldata.com
this engine?
2.5L (G25A4) Engine Firing order: 1-2-4-5-3 Distributorless ignition system

front of car.
engine
coil pak( 4,5,C.3,2,1)
rear fire wall

could be coil pak

A mechanic would check to see if the coil had voltage and a ground signal.

Yes start with the coil pak. There are three located on the front of the engine on the pass side, you probably know this. They are marked as to which cylinder each wire goes to, disconnect the wire for #5 cylinder, and if the engine misfire does NOT change, it is more than likely that Coil Pak. Replace it, and use dilectric grease on the two contacts when reinstalling it. Now, I have stumbled on this issue many times and if that does not cure the issue (I think it will), the coil module below the coil pack is probably bad...To remove this module, remove the coil paks, the electrical connector in front (has bolt holding it in) and I remember one bolt holding the module to the aluminum bracket.

Again, to be sure you can switch coil paks around to make sure it is a coil pak. When you switch the bad with a good, the misfire will follow the coil pak, if it does not it is the module.]

Hope this helps.

coil pack bad or ecm shot. unplug 1 wire from coil pak and hold close to metal while a friend cranks ignition. if you see a spark then paks are bad. no spark indicates bad ecm.

hi i dont mean to sound harsh but never assume anything with cars, if the engine cranks but wont start check for a spark at the plugs if no spark then you know that the problem is ignition or electrical in nature. if you have a good spark then you need to find out if you have fuel to the engine a good trick which i use is to spray some carb or injection cleaner into the manifold via a vacuum pipe dont spray it down the intake you might set yourself on fire ! if the engine kicks and attempts to run you know its a fuel fault . come back when youve established this.

Good Morning,
The coil pak is usually the problem with these buicks. You can buy a new one at your local auto zone store for around $50.00 and you can install it yourself in about 20 minutes! It just might be a quick fix without paying a mechanic to diagnose it. If you decide to install a new coil pak remember to disconnect one side of the battery first and above all only replace one spark plug wire at a time. Please let me know if I can be of further help and thank you for using FixYa!

Hi There,
I just wrote and now that I got your second message this is exactly how the faulty coil pak acts.
The car will get you from point A to point B but when you get back in the car and try to start it, it just cranks over. But wait awhile and it will start again! For $50.00 try a new coil pak, chances are this just might solve the problem. And by the way, your check engine light is not connected to the coil pak, that is usually an emissions problem and you can deal with that later. Please let me know if this helps you and thank you for using FixYa!

Try changing the coil pak. I had the same car with the 3.8 engine
the motor would crank but not start, I replaced the coil pak and that did it!