2001 Buick Century 3.1 66k miles, Very sluggish

[TGP37]

The trans is commanded to shift determing few things. It must not be in P/N, both RPM and MPH limits are reached for shifting and the trans is functioning properly.

I remember noting the auto trans fluid. If the level is too high or too low the trans WILL not operate properly. Many functions rely on the ATF being proper. As in it can not be burnt and must have the right amount. Also, too many people will balance the ATF from the dipstick reading when cold and off.

The shift is done by fluid pressure acting on a piston under springs. Low fluid will prevent the piston from being pushed, too much fluid will make bubbles and bubbles compress preventing the piston from shifting proper. The auto trans is connected to the crank via fluid. There is no solid connection, the ATF is used to transfer power from the crank to the trans. Burnt fluid, bubbled fluid, low fluid will hinder that.

The only way to properly fill the auto trans is to do so while the trans is hot (warmed up from driving) and the engine ON. otherwise the fluid level will not be correct.

If the fluid level is not correct, you will have shifting problems, you will have a lack of power, the car will burn a lot more mpg in fuel.

Don't assume anything, and tell me, did you check the ATF level when the fluid is warm and the engine is running? Is the fluid red or brown and smells burnt? Seriously, 1-2 qts too low and you'll have all kinds of trans issues.

[bigboi407]

The trans is commanded to shift determing few things. It must not be in P/N, both RPM and MPH limits are reached for shifting and the trans is functioning properly.

I remember noting the auto trans fluid. If the level is too high or too low the trans WILL not operate properly. Many functions rely on the ATF being proper. As in it can not be burnt and must have the right amount. Also, too many people will balance the ATF from the dipstick reading when cold and off.

The shift is done by fluid pressure acting on a piston under springs. Low fluid will prevent the piston from being pushed, too much fluid will make bubbles and bubbles compress preventing the piston from shifting proper. The auto trans is connected to the crank via fluid. There is no solid connection, the ATF is used to transfer power from the crank to the trans. Burnt fluid, bubbled fluid, low fluid will hinder that.

The only way to properly fill the auto trans is to do so while the trans is hot (warmed up from driving) and the engine ON. otherwise the fluid level will not be correct.

If the fluid level is not correct, you will have shifting problems, you will have a lack of power, the car will burn a lot more mpg in fuel.

Don't assume anything, and tell me, did you check the ATF level when the fluid is warm and the engine is running? Is the fluid red or brown and smells burnt? Seriously, 1-2 qts too low and you'll have all kinds of trans issues.

i did note in a previous post that i used TransTune in the transmission, the fluid had bubbles in it before the trans tune, drove it around 10 miles, and i dropped the pan, replaced the filter and pan gasket, i filled it up with brand new fluid to the correct level took it around for a spin, and it drives much better than it did before, The transmission has been opened before by a shop, when i dropped the pan the magnet had a good amount of metal on it

and yes i drove it around and double checked the level to make sure its in the right spot, i know with the engine off gives an innacurate reading,

the engine in my friends lumina Sounds SOOOO much stronger and better than the 68k mile 2001 3.1, i was test driving his lumina because it dies when it comes to a stop so i was punching it from a stop, a pony GT got next to me and the guy happened to had been looking around for someone to play with, i punched the accelerator in the lumina and left em behind, the guy in the pony didnt wanna come anywhere near the lumina my friend that owns the car was laughing at him,

this thread is getting kind of long and the topic of issue is changing im debating on making another detailed thread so were all on the same page

[bob442]

Do the CAT, do the fuel pump, and dont bother posting again till its all done also clearing the computer, or diconnecting the batter for a hour will help. you will have weird trans shifting issues due to the MAF having scewed readings because the CAT is plugged. remember, a motor is just a heart, an intake and a exhaust, if one is plugged or has restricion, you will have issues. Then you die.

[bigboi407]

Do the CAT, do the fuel pump, and dont bother posting again till its all done also clearing the computer, or diconnecting the batter for a hour will help. you will have weird trans shifting issues due to the MAF having scewed readings because the CAT is plugged. remember, a motor is just a heart, an intake and a exhaust, if one is plugged or has restricion, you will have issues. Then you die.

Sir, i do not mean to be a prick/smart ass by saying this but you obviously havent been reading my thread entirely.... i installed a BRAND NEW fuel pump, the cat will be gutted/modded tuesday

i was also never told "you will have weird trans shifting issues due to the MAF having scewed readings because the CAT is plugged" until now

Once again the things that have been done below:

New K&N Air Filter
New AC Delco Spark Plugs
New Bosch Wires
Cleaned MAF
New Fuel Filter
New MAP sensor
New Fuel Pump

[bob442]

MAF readings dictate line pressure in the transmission, and fueling. stating that you have installed a K&N filter element can cause an issue that i have seen before aswell, which is the oil in the filter element collects on the MAF sensors, some replace the sensor, i have cleaned it with a SENSOR SAFE cleaner, and a q-tip, and the vehicle was 100% after.

Now, i have not read every single post, but you seem to hopping around doing the CAT, you have a replacement, you dont, now your gutting it... now, i dont know everything, but the things that i have mentioned i do know.

TGP has a point with the motor burning antifreeze, causing the CAT to plug, and this can be from the most common issue with these motors which is the LIMG or a cracked head, or leaking head gasket, but there are easy tell tale sings which are white sweet smelling smoke from the exhaust, milky dirty oil, and low coolant levels. and the car will run like shit and over heat if any of these problems are present. Your issue is a loud as hell intake sucking noise, i had the same exact issue with my car, and discribed it the same. threw me for a loop, i thought for sure the LIMG's finally went on my car, but no, it was the CAT. it was replaced under warrantee and the problem was gone, car was loud, went fast-er, and shifted better.

Also, TGP is again right about the trans shifting issues and low fluid levels, but you will see that you dont have 4th gear, or 3rd pending on how low of fluid you are, its got a latter effect, the lower you are, the less high of a gear the trans will shift into.

[bigboi407]

MAF readings dictate line pressure in the transmission, and fueling. stating that you have installed a K&N filter element can cause an issue that i have seen before aswell, which is the oil in the filter element collects on the MAF sensors, some replace the sensor, i have cleaned it with a SENSOR SAFE cleaner, and a q-tip, and the vehicle was 100% after.

Now, i have not read every single post, but you seem to hopping around doing the CAT, you have a replacement, you dont, now your gutting it... now, i dont know everything, but the things that i have mentioned i do know.

TGP has a point with the motor burning antifreeze, causing the CAT to plug, and this can be from the most common issue with these motors which is the LIMG or a cracked head, or leaking head gasket, but there are easy tell tale sings which are white sweet smelling smoke from the exhaust, milky dirty oil, and low coolant levels. and the car will run like shit and over heat if any of these problems are present. Your issue is a loud as hell intake sucking noise, i had the same exact issue with my car, and discribed it the same. threw me for a loop, i thought for sure the LIMG's finally went on my car, but no, it was the CAT. it was replaced under warrantee and the problem was gone, car was loud, went fast-er, and shifted better.

Also, TGP is again right about the trans shifting issues and low fluid levels, but you will see that you dont have 4th gear, or 3rd pending on how low of fluid you are, its got a latter effect, the lower you are, the less high of a gear the trans will shift into.

its not that i have been hopping around doing the CAT, Its her car and i dont live with her, i dont work because my back is shot and cant work even if i was given a job cause i cant stand for long periods of time and i have sciatic nerve damage, so every few weeks i cant walk. that being said with low income things have to be done cheaply....

im getting her car over here tomorrow, I HOPE, so i can tackle the Cat once and for all

My dad Double checked the tranny fluid level for me, he confirmed that it is perfect, Then he played with the throttle and he seems to think that the motor is being restricted by more than just clogged exhaust, Check out these videos below... We both Clearly understand that the engine is being restricted due to a clogged cat, but whats this knock sound?






there is no water in the oil or oil in the water, all fluids are where they should be... when i blew the head gasket in my CRX i had emulsified gray goo in the radiator, no such thing has occured in this buick..

Note: i started to think about this Century, and it has NEVER Ran anywhere near as good as my friends lumina in the time she has own the car, yeah it used to drive pretty good, but it has never set me back in the seat, nowherere close to like the lumina did, she got her car with 50k miles from her mom.. the lumina i speak of has well over 100k

[TGP37]

That noise, could be the timing chain, loose metal. It may be metal debris in front of the cat. It could be the cat itself. It could be a bolt resting on a heat shield.

Don't start spinning in circles. One thing at a time. Swap the cat and go from there.

I would also try some top end cleaner. I use seafoam, others use other stuff, but it's all similar. IF the cat is clogged I'd imagine the EGR has been over worked and lots of soot made it's way into the intake.

The noise COULD be a loose, stretched timing chain. But it's pointless to dig deeper until the cat is swapped.

[bigboi407]

That noise, could be the timing chain, loose metal. It may be metal debris in front of the cat. It could be the cat itself. It could be a bolt resting on a heat shield.

Don't start spinning in circles. One thing at a time. Swap the cat and go from there.

I would also try some top end cleaner. I use seafoam, others use other stuff, but it's all similar. IF the cat is clogged I'd imagine the EGR has been over worked and lots of soot made it's way into the intake.

The noise COULD be a loose, stretched timing chain. But it's pointless to dig deeper until the cat is swapped.

Trust me Im not spinnin in circles..... i was a little frustrated with this car, but im past that and really at the point where i dont care if i can fix it or not, if i can, i can but im not gonna hold my breath, i guess her mother handed her a sour lemon (And Yes on purpose)

i did run seafoam through the engine, but i did 1/3 of the can through the booster hose, cut the car off for 5 minutes, and cranked it on, let it sit for another 5 minutes then drove it around and the white smoke only lasted about 1/4 mile or so.

today im gonna pull down the cat, gut it and let my brother work his magic, he says the hell with a new cat because he knows he can trick the 2nd sensor to read as if it has a perfect working Cat.. i will report later today with my results

[TGP37]

Spark plug non-fouler

Anything else won't work. Unless he is building a circuit to interact with the PCM. Or he has a tuner that can turn off the o2 sensor from reporting an error.

[bigboi407]

Spark plug non-fouler

Anything else won't work. Unless he is building a circuit to interact with the PCM. Or he has a tuner that can turn off the o2 sensor from reporting an error.

the cat is removed and 2nd O2 sensor is not installed or plugged in.. my brother wasnt able to come by and rig it up, yes he said a spark de-fouler is the way to get it done cheaply

i Took it around, OMG..... tires peeled out and i got sucked into the seat... went from 0-80mph in Seconds.. i didnt know i was doing 80 until i looked down @ the speedo because im so used to punching it to get to 40mph in 3 miles distance..

im gonna talk to my dad and see if i can get the guts of the Cat knocked out, because of the U bend where the O2 sensor is, seems difficult to gut it without cutting it... i hope my dad can gut it, but the car is running without it and it takes off GREAT, shifts perfectly fine, Bob442 is correct when he said MAF dictates line pressure, because it GOOOES..

I never knew Catalytic converters could cause SOOOOO many problems, Now i know...

[bob442]

Good stuff, if you can convince the owner of the car to fork out for a magnaflow cat there only 80$, but hopefully you don't experience any fuel economy issues down the line, that o2 sensor just needs to be zip tied up and out of the way of debris, it's basically got to read clean air, that or spacing it out on the factory bung.


Sent from my iPhone using my iPhone at work cuz I have nothing to do

[TGP37]

Good job man. See, just a little labor. Since you had to work hard on your GF's car, she should reward you, lol. Beer, football and a half time hummer.

O2 sensors have heated elements. They can potentially start fires if unprotected. I would just unplug it until you can mount it properly or not at all. You can have a shop weld an O2 bung on a steel pipe.

The non-fouler works typically, but the best option is to find a tuner that can turn off the downstream o2 sensor.


Glad you got it fixed!

[Fireball]

Awesome stuff man!
On the upside you've replaced so much in searching for the problem the car will be in great shape for years to come!

[pocket-rocket]

I just put a new Walker cat on my truck this past weekend because I was tired of the way it sounded after gutting the almost 200k mile original. I only paid around $45 for it. Also I don't get choked or teary eyed when around the back of my truck when it's running now, lol.

[bigboi407]

Good job man. See, just a little labor. Since you had to work hard on your GF's car, she should reward you, lol. Beer, football and a half time hummer.

O2 sensors have heated elements. They can potentially start fires if unprotected. I would just unplug it until you can mount it properly or not at all. You can have a shop weld an O2 bung on a steel pipe.

The non-fouler works typically, but the best option is to find a tuner that can turn off the downstream o2 sensor.


Glad you got it fixed!

i just removed the cat and unplugged the 2nd o2 sensor, CEL is on and its getting Awsome milage versus before.. still dont know what were gonna do about the cat.. i say cut it open and gut it, then rig the o2 sensor with the non fouler for time being... most people in FL dont know wth a catalytic converter is, Hell florida born and raised folks dont know about emission requirements or emission testing... it just DOES NOT exist in FL and i grew up around straight pipes..

in working on these newer cars i feel like a total noob.. makes me wanna get a 2000s impala with a blown motor and rebuild it and master these newer cars, thats if my back will get better.. i havent had any scatic attacks because i refuse to lift weight or do any strenuous activity

Awesome stuff man!
On the upside you've replaced so much in searching for the problem the car will be in great shape for years to come!

it actually needed all those things replaced ANYWAYS, i was the first person to touch the engine since it was built.. only thing that has been done by ANYONE is a tranny shop worked on the transmission because shortly after buying it, somethin went bad in the tranny..