1980 Buick Century Not Working (3.8 2 barrel N/A) HELP!!

gbodybuick

Not-quite-so-new-guy
Nov 30, 2023
34
9
8
Hi Everyone. My buick century is having some sudden major issues. It suddenly has a extremely hard time starting, and sputters out when you put it in gear (you can manage to having it not sputter if you put it in gear while at 1.5k ish rpm holding the gas and brake, but when you try to drive it it dies immediately.

Little bit of backround: Up untill now, I had the car for 2 years no issues, prior it was sitting for 10 years. I had the carb professionally rebuilt and tuned, replaced the distrubuter, spark plugs, ignition coil, battery, alternator, fuel filter, and many non engine related parts including replacing all the fluids. The car had 133k miles on it when I bought it and now has 137k. The other day I drove it to work, did a 5 hour shift, went back to start it and it started fine (although my gut was telling me something was a tiny bit off but nothing relevant). The car high idled for a few minutes and seemed to be misfiring slightly but no shaking, just a tiny mis vibration every couple seconds. I kicked down the gas and let it idle low. About 4 minutes later while i was waiting for it to warm up, it just completely died and I couldn't get it started at all. Next day I went back, wailed on the engine and starter, and only ended up flooding it, was eventully able to get it running by cranking the crap out of it and burning out all the gas. It high idled fine but died when I lowered the idle and also when I tryed to drive it. I had the carb cleaned after that and was finally able to get it to idle.

Where I am at now: Even though the car could idle, it is still extremely hard to get it started, it usally just floods or trys to fire but doesnt and ends up making horrible starter gear friction noises while it keeps failing for 5 minutes untill it actully runs. Once it runs it seems fine (if you turn it off even while warm you have to start the whole process over). However the moment you drop it in gear it will die completely. You can, drop it in gear without dieing if you somewhat nutral drop it while holding the brake, but if you try to move foward, it will die instantly.

Possible causes: My only thoughts are the engine might have a vacum leak problem and the transmission might have a torque lock problem. Either way, would be kinda weird for them both to fail simultainusly.

It has always had a very leaky transmission and a jult when shifting from first to second, though it was always fine untill now. When the engine runs now, theirs also a very visable amount of smoke coming from the engine bay and a sharp hiss.

Any help would be greatly appreciated, It has a very solid body and I need the car to get to work. I would like to fix it myself as I can't through more money into this. Thanks!
 

gbodybuick

Not-quite-so-new-guy
Nov 30, 2023
34
9
8
As a quick check, the first thing I would do is put a timing light on it. The distributor drive gear may be wonky.
Thanks for the reply! Im not too familar with timing lights, is it a external tool to check the cars timeing? Are you implying that my timeing could be off? Lmk thanks!
 
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John Canon

Apprentice
Apr 19, 2022
87
58
18
Vancouver Canada
There are TubeVideos about using a timing light. Basically it flashes a strobe light whenever it detects a spark, after you clip the sensor onto a spark plug wire. It is used to check and to adjust the spark timing of an engine, with the number 1 spark plug being the reference point. You could clip it onto a distributorless engine and see the timing, but there is no way to change the computer controlled spark.

It is a traditional tuneup tool for checking distributors. The rotating distributor spins to produce the spark and send it to each correct spark plug in the right order and timing.

The distributor has a long shaft that goes down into the engine, and it is driven from the engine camshaft. A gear on the bottom of the distributor meshes with the engine camshaft.

If that bottom gear has stripped or slipped, your spark timing will be incorrect, causing power loss, rough idle, backfiring, stalling, and erratic operation. The symptoms match your description, and using a timing light is a quick way to test and maybe eliminate spark as a cause.
 
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SoFloG

Royal Smart Person
Mar 9, 2016
1,107
1,258
113
South Florida
Check your plugs. 4k miles doesnt seem like much but with today's gas in an older vehicle you'd be surprised. Could you have a plug wire loose/ grounding out? I'd pull a couple spark plugs and see what they look like. Do you have a fuel filter?
 
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gbodybuick

Not-quite-so-new-guy
Nov 30, 2023
34
9
8
Check your plugs. 4k miles doesnt seem like much but with today's gas in an older vehicle you'd be surprised. Could you have a plug wire loose/ grounding out? I'd pull a couple spark plugs and see what they look like. Do you have a fuel filter?
Pulled the plugs they were fine, has a fuel filter.
 

gbodybuick

Not-quite-so-new-guy
Nov 30, 2023
34
9
8
There are TubeVideos about using a timing light. Basically it flashes a strobe light whenever it detects a spark, after you clip the sensor onto a spark plug wire. It is used to check and to adjust the spark timing of an engine, with the number 1 spark plug being the reference point. You could clip it onto a distributorless engine and see the timing, but there is no way to change the computer controlled spark.

It is a traditional tuneup tool for checking distributors. The rotating distributor spins to produce the spark and send it to each correct spark plug in the right order and timing.

The distributor has a long shaft that goes down into the engine, and it is driven from the engine camshaft. A gear on the bottom of the distributor meshes with the engine camshaft.

If that bottom gear has stripped or slipped, your spark timing will be incorrect, causing power loss, rough idle, backfiring, stalling, and erratic operation. The symptoms match your description, and using a timing light is a quick way to test and maybe eliminate spark as a cause.
Very interesting, could you link the tool?
 

John Canon

Apprentice
Apr 19, 2022
87
58
18
Vancouver Canada
Start with this link: https://www.carparts.com/blog/a-crash-course-on-how-to-use-a-timing-light/

A distributor has 3 inputs that determine the spark advance while the engine is running.
1> The vacuum advance system (responds to engine load)
2> The mechanical advance system (responds only to engine speed RPM)
3> The initial setting (base timing) set by turning the distributor and tightening the lock screw.

If you want to customize these settings, then choose a timing light with more features.
 
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gbodybuick

Not-quite-so-new-guy
Nov 30, 2023
34
9
8
Start with this link: https://www.carparts.com/blog/a-crash-course-on-how-to-use-a-timing-light/

A distributor has 3 inputs that determine the spark advance while the engine is running.
1> The vacuum advance system (responds to engine load)
2> The mechanical advance system (responds only to engine speed RPM)
3> The initial setting (base timing) set by turning the distributor and tightening the lock screw.

If you want to customize these settings, then choose a timing light with more features.
Thank you, also which spark plug is the #1 spark plug (Its a 1980 3.8 2 barrel n/a v6). Also I recall you telling me that this could be causing alot of my symptom's, and while it does make weird noises and runs erratically sometimes, it does (once you get it running after battling it) run perfectly normal until you try to drive it.
 

John Canon

Apprentice
Apr 19, 2022
87
58
18
Vancouver Canada
Make a mark or label before removing or loosening anything..

Your comment "runs normal until you try to drive it" belongs in the G-Body Hall of Fame!

It is right up there with "how did it run before you painted it?"
and "did you try to drive it without turning?"

1980 Buick 3.8 Wires.jpg
 
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