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[slowbuick]

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!

 

[John Canon]

As a quick check, the first thing I would do is put a timing light on it. The distributor drive gear may be wonky.

 

[John Canon]

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.

 

[SoFloG]

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?

 

[John Canon]

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.

 

[John Canon]

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?"

 

[78Delta88]

By all your symptoms and your car being older than my daughter. Common problem with Buick, Chevy and Pontiac, your nylon coated timing gear (cam) shredded the nylon and your timing chain jumped.

Accounts for poor idle hard starting and will run at very high RPM until you put a load on it and it dies.

There are a few other things to check first, because the engine is a system... Air... Fuel... Fire and then all contained in a mechanical device regulated by crank position, valves, valve position, compression and gaskets that supposedly keep things where they should be.

First things when keeping these old beasts. Get good with; vacuum gauge, fuel pressure guage, volt and amp meter (VOM) and timing light.

**Not knowing how is just the reason needed to learn it. Or throw money at mechanics that are absolutely clueless without a scan tool.

 

[78Delta88]

That's good news. So if "Fire" is ok then look at the others.. Remember. Air....fuel....fire is the mantra. Of course also based on good compression, good head gaskets, etc...

Sputtering under acceleration also possible points to coil getting or being weak.

Also points to fuel insufficiency. These are just possibilities. But as items get ruled out you get closer to true root cause and the item to fix.

 

[Sweet_Johnny]

Are you 100% sure it's flooding or is it just not trying to fire?

Just for fun, drop your gas tank and check the hoses on top of it. I saw the ones in front of the tank looked good on my Cutlass when I had similar issues and I blamed the carb, distributor, and vacuum leaks. It was this:

My car had trouble starting and required starting fluid to get going. It would die if left to idle, especially in gear. It would only run between about 1500-3000 rpm- too low or too high and it starved to death. The problems initially presented as potential carb and ignition issues.

 

[spongbob]

Yes take your spark plug out and see what color they or it are ? Is the plug insulator black have a fluffy black or look like it's painted black .if so you can try changing plugs....or sandblasting old plugs....if you find this condition. Your likly glass glazing your spark plugs from a leaky float valve ( dirt on float valve ect ).check the inside of the distributor cap for cracks or carbon tracks....regardless of timing light ,take the distributor cap off and turn the engine with a breaker bar or by hand first turn it in one direction about an inch ( of the main pully on end of crankshaft) then turn it back the opposite direction .do this several times while you stare at ( watch) the rotor button if your rotor changes directions with the crankshaft before it moves say 25 degrees ( (about an inch of crank rotation) in opposite direction,then dismisse the timing chain concerns but it it takes Over and inch of crankshaft turning as far as when changing direction you should seriously consider removing the timing cover to address the excess timing chain play....check the carb secondary throttle plates ( butterfly) to see it is not sticking open (ignor this on 2 barrel)slightly.maybe oil the shafts check the distributor centrifugal advance weights put a spot of oil on them and there pins [Ignor this if distributor has no weights]..if possible get the car up to warm temperature and then turn off the motor and pull some spark plugs are any fouled ( black or black oily ?) If so change them if they have too much oil on the insulators ( nose of plug) and your valve covers are leaking oil when you change them plugs put a small smidgen of grey silicone on the last sealing threads to prevent oil from leaking in on the threads and accumulating. If there is not spark plug fowling ? you could try wireing the chock to half on and see if your car still stalls( temporary test with steel wire) in gear...if this helps check to see if the brake vacuum booster has a vacuume leak ( cracked diaphraim) and the fuel filter ( stoped up ?) and gas tanke hose route for cracks or pinholes .check the oil for gasoline in it also check any filter in the front of carb if you haven't? If you decide too check the main jets in the old carburetor could have one blocked by debrie ,rust ect...good luck