2001 Buick Century 3.1 66k miles, Very sluggish

[TGP37]

Not sure about access panel. My 96 GP needs the tank dropped.

Kick down and rev over?

You could be facing more then 1 problem. That can easily compound the situation making it hard to diagnos effectivelly. I do know running lean can change the vacuum, and in some instances I had backfire into the intake manifold.

We have a waste spark system, which means the spark plug fires in the power stroke AND the exhaust stroke. If you are running lean enough, having misfires, sometimes the fuel will ignite in the exhaust stroke. I have seen fire shooting out of a vacuum line once with a friends car.

If the engine runs properly, hardly ever does the fuel ignite in the waste spark period...it is already combusted. But an engine running badly, often the wastespark can ignite the fuel.


It is really hard to say what is happening w/o being there myself. I think you are close to fixing it, the cat and pump are both good places to check/replace....considering the symptoms and history.

Never assume anything.....in example, one bad part can mimic another issue.

[bigboi407]

Not sure about access panel. My 96 GP needs the tank dropped.

Kick down and rev over?

You could be facing more then 1 problem. That can easily compound the situation making it hard to diagnos effectivelly. I do know running lean can change the vacuum, and in some instances I had backfire into the intake manifold.

We have a waste spark system, which means the spark plug fires in the power stroke AND the exhaust stroke. If you are running lean enough, having misfires, sometimes the fuel will ignite in the exhaust stroke. I have seen fire shooting out of a vacuum line once with a friends car.

If the engine runs properly, hardly ever does the fuel ignite in the waste spark period...it is already combusted. But an engine running badly, often the wastespark can ignite the fuel.


It is really hard to say what is happening w/o being there myself. I think you are close to fixing it, the cat and pump are both good places to check/replace....considering the symptoms and history.

Never assume anything.....in example, one bad part can mimic another issue.

say your in 2nd gear and you hit the gas, the transmission shifts/kicks down and the car is supposed to Launch off, these cars dont have an RPM guage so it hits its rev limit then it does this noise

[bigboi407]

so i got the new fuel pump in the mail today

ive found the access panel and need the back of the backseat out, how do i remove it? i see two nuts and 2 clips, i need the back out of the way so i can get to the access panel from the inside cause i cant ball up in the trunk and replace the pump... wont happen, im a big dude hence my username


it is driving worse and worse as in Slower and Slower, so shes gonna buy the cat after i put the pump in tomorrow,

[TGP37]

Don't know about buicks but it may be something where you remove the butt part of the seat, then get access to the rest. If you can pull the pump out from the top, that is nice. Won't have to mess with tank straps and disconnecting the fuel filler lines, feed/return lines, evap lines, etc.

ALLDATA is a good resource for vital info on your car. I've used it countless times for diagrams, pics, bolt locations.....cost is the same as a Haynes Manual but far superior.

[bigboi407]

Don't know about buicks but it may be something where you remove the butt part of the seat, then get access to the rest. If you can pull the pump out from the top, that is nice. Won't have to mess with tank straps and disconnecting the fuel filler lines, feed/return lines, evap lines, etc.

ALLDATA is a good resource for vital info on your car. I've used it countless times for diagrams, pics, bolt locations.....cost is the same as a Haynes Manual but far superior.

I put the New Fuel pump in, there is infact an access panel to get to the pump, the old pumps screen was BLACK and pretty gross, tank was clean, i had some trouble with the gas guage so i had to take it Back out and bend the new sensor so it would read correctly, But it STILL Drives like crap, SOOOO she will be ordering a new Catalytic Converter and ill put it in when it gets here, How do i disconnect the end closest to the engine? by pulling the motor forward like i did to change the plugs or can i do it from underneath?

yeah i know the hanes manuals suck... im not soo indepth with the GM cars cause i havent owned one in years and didnt do much to it, i know with Hondas you can go to a dealers parts page and get blown up parts and pretty much buy any little peice that is available, i tried to do the same with the GM dealers all the ones i pulled up didnt have em, but the parts department did...

not bashing this site when i say this, the 1st gen crx/3rd gen civic website i am a member of, they have ALL Factory Service Manuals which if any dummy followed them correctly they could EASILY rebuild the whole car, i learned how to take apart my 5 speed trans from those pages until i fully understood how everything works and goes together, now i dont need the FSM, and its actually easier for me to jumble the tranny internals into a pile and pick everything out from largest to smallest until the countershaft is assembled.. believe me when i tell you guys i miss the comfort ride from time to time, id consider getting an impala with a blown motor or bad transmission and build it like new myself.... i missed out on a 2002 impala Ls blown HG for $900 some time ago, if i seen a 1991 Lesabre Custom in Perfect shape as far as the body goes, id deffinately get it, i miss the backwards hood and all the room that car had.. imho it had more room than the impala and her century

[bob442]

return the fuel pump, replace the CAT, its what i heard, its what your hearing, its the cat. if the EGR were to be plugged it would be from over fueling no? or old plugs, or and a plugged cat?

[bigboi407]

return the fuel pump, replace the CAT, its what i heard, its what your hearing, its the cat. if the EGR were to be plugged it would be from over fueling no? or old plugs, or and a plugged cat?

well the new fuel pump was purchased on ebay for $50 shipped, considering what ive been told about changing a clogged fuel filter, id rather keep the new pump in there, the new pump plus a Magnaflow CAT is $225 if the Cat is $175, AZ wanted $260 for a pump and $242 for a Cat.. seems like a hella cheap deal to me.. pump comes with a warranty per his ebay ad (99% feedback) and i had to cut the old plug anyways

as for removing the cat whats the best way to do so? pull the motor forward or can i get to it from underneath? i dont like crawling under cars unless i HAVE TO

[88GTRacer]

Buy car ramps. They cost about 30-50 bucks and rent a pipe cutter at AZ if you don't have a saw saw.

[bigboi407]

Buy car ramps. They cost about 30-50 bucks and rent a pipe cutter at AZ if you don't have a saw saw.

HUHH??? its direct fit no cutting required, who need ramp i got about 3 sets of stands... still doesnt change the fact i need to get under the car stands or ramps.......

[bob442]

lube the bolts, take a 15mm deep socket and extensions and a ratchet. Raise car atleast 1 foot, crawl under car. if you got a new cat, then you have to cut the old one out, if you got a new downpipe with cat, then its a bolt on. Technically, you could "bolt on" a cat, but that involves using those grabage clamps. people who use those should be shot.

[TGP37]

Two ways you can approach this.......

Remove the cat by unbolting the exhaust upstream and downstream. It will be a length of exhaust pipe. Cut the old cat out. Try to cut out a length equal to the length of the replacement cat. Keep in mind you will want an inch extra on each side for overlap. So if the replacement cat is 14" long, cut out 12" worth of space with the old cat. If the replacement is too short, get some pipe at any autoparts store. Keep in mind you want overlap so pay attention to inner diameter versus outer diameter.

You then will want to clamp it well. Don't use the cheap horseshoe like clamp. Get a band clamp for overlapping joints. They seal better.....but if you can get it welded, do it.

Do NOT use the flex pipe found in Advance Auto Parts. It leaks after time and the Cat gets REALLY hot. So do not use anything but metal. No RTV or any other non metal gaskets.

Great band clamp for something like this. You do not want a leak under neath the chassis. It WILL get into the cab easily an poison you over time.

If it is a direct fit, you gotta simply unbolt it.

All of this means you will be under the car. Be sure to use proper jack stands on solid, level ground. Do NOT get under the car with just jacks holding it up. A big guy like you won't stand a chance if it falls on you. Don't be a statistic, be safe.

[bigboi407]

Two ways you can approach this.......

Remove the cat by unbolting the exhaust upstream and downstream. It will be a length of exhaust pipe. Cut the old cat out. Try to cut out a length equal to the length of the replacement cat. Keep in mind you will want an inch extra on each side for overlap. So if the replacement cat is 14" long, cut out 12" worth of space with the old cat. If the replacement is too short, get some pipe at any autoparts store. Keep in mind you want overlap so pay attention to inner diameter versus outer diameter.

You then will want to clamp it well. Don't use the cheap horseshoe like clamp. Get a band clamp for overlapping joints. They seal better.....but if you can get it welded, do it.

Do NOT use the flex pipe found in Advance Auto Parts. It leaks after time and the Cat gets REALLY hot. So do not use anything but metal. No RTV or any other non metal gaskets.

Great band clamp for something like this. You do not want a leak under neath the chassis. It WILL get into the cab easily an poison you over time.

If it is a direct fit, you gotta simply unbolt it.

All of this means you will be under the car. Be sure to use proper jack stands on solid, level ground. Do NOT get under the car with just jacks holding it up. A big guy like you won't stand a chance if it falls on you. Don't be a statistic, be safe.


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thank you for all ur help, i spoke with my brother and hes gonna assist me in gutting the cat and rigging the 2nd O2 sensor so it reads as if the cat is still inside and working, we live in Florida, theres Nothing about emissions here, hence why i never knew a cat could cause so much trouble, ive never had a vehicle with one installed, besides my 91 lesabre and i didnt drive it for that long either

if i were to buy the magnaflow one in the future it is a 100% Direct Fit no cut required cat... i have more rims/tires than you can shake a stick at, so i use some to make sure if it does fall it lands on tires and not on me... i can go under cars and have for many years, but with my back problems i try to avoid anything that would cause me to be stuck in bed with sciatica which includes working under cars or bending down into the engine bay, hell i cant even stand for more than 20 mintues... but im not gonna pay someone to work on my car or her car bcause i dont trust anyone elses work, UNLESS its something i absolutely cannot stand to do or just dont have the tools with power to complete the job at hand, but i have a guy i buy tires from that will do anything i pay him to do

the worst danger ive encountered in mechanic work at home was a complete D15 Honda engine falling from the engine crane and it bounced off my knee before it put a chip in the concrete below..... luckily it didnt break anything and i had jeans on, or id have deff been screwed, i always make sure stands are in a spot where the car if even shaken wont budge off the stand, aside from that incident, ive had plenty of knuckle busting experiences, or how id like to call it "The Craftsman Snap!" never in my life will i ever buy craftsman (my dad did), we have a 3/8" snap on rachet that has outlived all the craftsman rachets including the big torque wrench, hell ive got 3 broken Craftsman rachets i havent taken back because i know how much they suck

[bob442]

the guy i had sold my new down pipe to had a 02 century, and he had the same problem, gutted the cat, tide up the O2 so it read 'properly' and the thing still ran like crap, once he put mine in, he called me back and said the thing has never ran so good. Just a heads up.

[TGP37]

Cats can get clogged by silicon deposits from leaking coolant. They can also plug up from running too rich for a length of time.

There are things called Test Catalytics which look like cats but are actually straight pipe inside. Though I like the tone a cat adds to the exhaust note.

Be sure to scrap that old cat. Might get anywhere from $50-90 for it.

[bigboi407]

Cats can get clogged by silicon deposits from leaking coolant. They can also plug up from running too rich for a length of time.

There are things called Test Catalytics which look like cats but are actually straight pipe inside. Though I like the tone a cat adds to the exhaust note.

Be sure to scrap that old cat. Might get anywhere from $50-90 for it.

okay, i just drove my friends Chevy lumina, it has a 3100 and it HAULS ASS compared to my girlfriends Century, m gonna try gutting the cat and rigging the 2nd o2 sensor to run without the cat guts, what do i got to lose?

What would cause the transmission to not shift from 1st to 2nd while the gas pedal is all the way down, because his car takes off like a rocket, shifts through the gears fine, isnt throwing any codes, im gonna assume theres another problem i am not adressing because his Lumina IS VERY VERY Fast Versus the Century, his Lumina dies when it comes to a stop and when i put it in Drive from park, what would cause that? it takes off like a rocket if the pedal is floored, when driving if i press very light the transaxle will rock, i may make another thread for his vehicle

i hope we can get the Century fixed to run as good as his Lumina, i dont wanna throw in the towel with the buick, but if i cant get it to run normal, whats the point of keeping it