2001 Buick Century 3.1 66k miles, Very sluggish

[bigboi407]

I'm leaning with sappy. Those cats can be a hard catch. How well does it free rev? If you can get it to bog during free rev, drop the front pipe at the manifold and then try free reving again. If she spools up and don't bog with the open exhaust, change the converter. Then hurry up and find out what clogged the converter, because they dont clog by themselves.

The trans kicking down could be because the ecu is detecting high load from a clogged exhaust.

Thanks for the input, my honest opinion is that it may be Quite a few problems ALL adding up to give me the problems i currently have, i will take video of the free rev and also video of the bog, TODAY because i wanna get this over with.. Free rev it does bog BUT only on High RPM's and its intermitten not Every time i touch the gas pedal(Will Double Check to confirm), when driving it only does it on Low RPM's and throws a misfire code, i dont believe that a clogged cat could cause the engine to throw a misfire code, or is that possible??

its also running hotter than average, would the bosch +4 plugs have anything to do with that? ive read that some people have problems and others say theyre wonderful plugs, i changed the plugs AFTER the seafoam, i like bosch over cheap brands anyday, i run em in my civic i and i didnt notice much difference versus the old plugs it had.

[60dgrzbelow0]

the PCS Sounds like the culprit, it doesnt do the HARD shifting where others describe it feels like the transaxle is rocking with every shift, but as for the rest its dead on, and i even told her it feels like a valve isnt doing its job..... the acceleration shudder happens Badly, Say if we drive parking garage when going up to the next level it shudders not hard, just a constant shudder that cannot be mistaken by anyone with any knowledge in mechanics.

Could i change this valve myself, easily? ive rebuilt my spare 5 speed transmission and am confident i could knock this out if need be, im willing to bet Getting to the transmission is gonna be more of pain than actually replacing the valve

As you have observed, transmission work is always a long road with no turns in it... Have a look at these generic videos to get an idea of the PCS hardware design and functionality as well as the complexity in the diagnoses and repairs that may ensue. I am not very familiar with the transmission/transaxle arrangement in the "East-West" FWD engine layouts but others here can counsel you on whether or not the biggest problem has to do with gaining access to the tranny's innards b4 you can even replace such a simple solenoid device:

http://www.youtube.com/watch?v=2UAeYUtc1hA

http://www.youtube.com/watch?v=OGckmJK2rNQ

http://www.youtube.com/watch?v=JUSSj_2eHUY

http://www.youtube.com/watch?v=dkLQpezVk9I&feature=related

There may be another culprit here: The TPS (Throttle Position Sensor) may be out of sync or failing and give some jumpy signals to the PCM that will cause that bizarre shifting phenomena. Take a peek at THIS video for an example:

http://www.youtube.com/watch?v=f3nfayKOvsQ&feature=related

PS..."Yeah...Now about those TPS Reports... Did you get the Memo about putting on the new Cover Sheets?"

http://www.youtube.com/watch?v=Fy3rjQGc6lA

[bigboi407]

As you have observed, transmission work is always a long road with no turns in it... Have a look at these generic videos to get an idea of the PCS hardware design and functionality as well as the complexity in the diagnoses and repairs that may ensue. I am not very familiar with the transmission/transaxle arrangement in the "East-West" FWD engine layouts but others here can counsel you on whether or not the biggest problem has to do with gaining access to the tranny's innards b4 you can even replace such a simple solenoid device:

http://www.youtube.com/watch?v=2UAeYUtc1hA

http://www.youtube.com/watch?v=OGckmJK2rNQ

http://www.youtube.com/watch?v=JUSSj_2eHUY

http://www.youtube.com/watch?v=dkLQpezVk9I&feature=related

There may be another culprit here: The TPS (Throttle Position Sensor) may be out of sync or failing and give some jumpy signals to the PCM that will cause that bizarre shifting phenomena. Take a peek at THIS video for an example:

http://www.youtube.com/watch?v=f3nfayKOvsQ&feature=related

PS..."Yeah...Now about those TPS Reports... Did you get the Memo about putting on the new Cover Sheets?"

http://www.youtube.com/watch?v=Fy3rjQGc6lA

looks like ima have to skip gettin my feet wet and just jump in head first... Thank you for the info provided along with everyones input, once i get some time to myself ill look over all the info

[bigboi407]

Took it to AZ today got another code Read... EGR Fail, so i bought another one, and swapped it out, THEN

today i have pulled ultimate retard move, i confused the wires and now it wont crank on........ im retarded when it comes to wiring per firing order

Can someone please tell me where i run the wires from the coil pack numbered 1-4-6-3-2-5

Cylinder numbers are

Back
1-3-5
x
2-4-6
Front

^ Correct? Which 3100 am i working on lg8? Firing Order 1-2-3-4-5-6?


how would the cylinder numbers wire to the coil pack? Like 2 doesnt go to 2 on the pack and 3 doesnt go to 3 on the pack so how does it go? i need to get this figured out ASAP as this is the only transportation we have at the moment, call me retarded if youd like XD

EDIT: She has now called me retarded because i cant figure out the order in which the plugs go

[Merc6]

Yes you have LG8 engine.

3.1 liter V-6 VIN "J"

[60dgrzbelow0]

BB...

How are your Spark Plug Wires arranged...looms holding them in place ok? ,,,and not hitting anything hot from the exhaust to cause a direct short? This may sound crazy... and OT (Off Topic) ...but ...FWIW...after not being able to get the proper separation of each wire via standard looms and even speciality looms. to prevent the sympathetic radio interference and strange misfires on my '93 LT-1...I finally tried using a handful of very large ZipTies and sort of rigged my own separators between wires. with one around the body of each wire and two sort of "chain-linked" in between and that absolutely eliminated the problem in a very cheap and reliable manner. No matter how much or in whatever way they can be moved around under the the hood and around the engine...the wires cannot come close enough to cause any more problems.

[bszopi]

Get rid of the Bosch +4s, as they are TERRIBLE in this engine. Replace them with just standard AC Delco plugs for your car, and I bet many of your problems will disappear.

[95SleeperAcheiva]

Get rid of the Bosch +4s, as they are TERRIBLE in this engine. Replace them with just standard AC Delco plugs for your car, and I bet many of your problems will disappear.

Ditto!

[TGP37]

Check the plastic hose that runs to the back side valve cover. If that comes loose, the engine will draw unmetered air and run lean. And you will hear the vacuum leak.

Check fuel pressure, you may have a dying pump. One way to tell is to put it in park and floor it so the engine bounces off the rev limiter. After 2 or 3 bounces it may start to bog down.......low fuel pressure.....probable clogged filter or bad pump. But idealy you want to check pressure at the Schrader Valve with a rental gauge.

Some people will tape the pressure gauge to the windshield and test it while driving to see if the pressure is failing under load.


If you ever had changed a fuel filter that was partly/mostly clogged, anticipate a dead/dying pump.




Also, this just came to mind.......check spark plug cables. Removing used cables will often break them and the resistance skyrockets. The engine will idle fine under the weak spark but the spark will arc to the block if the cable is busted due to resistance. Use a multimeter and check the cables for resistance.

[bigboi407]

Check the plastic hose that runs to the back side valve cover. If that comes loose, the engine will draw unmetered air and run lean. And you will hear the vacuum leak.

Check fuel pressure, you may have a dying pump. One way to tell is to put it in park and floor it so the engine bounces off the rev limiter. After 2 or 3 bounces it may start to bog down.......low fuel pressure.....probable clogged filter or bad pump. But idealy you want to check pressure at the Schrader Valve with a rental gauge.

Some people will tape the pressure gauge to the windshield and test it while driving to see if the pressure is failing under load.


If you ever had changed a fuel filter that was partly/mostly clogged, anticipate a dead/dying pump.




Also, this just came to mind.......check spark plug cables. Removing used cables will often break them and the resistance skyrockets. The engine will idle fine under the weak spark but the spark will arc to the block if the cable is busted due to resistance. Use a multimeter and check the cables for resistance.

has brand new wires, plugs and i just changed a fuel filter that was somewhat clogged, i dont think it has anything to do with the fuel pump, a dying fuel pump is possible?? i thought they either A. Worked or B. Didnt work

These symptoms the car has had for a while, nothing i have done has cause new problems, it will not bog @ high RPMs only when under load accelerating between 2nd-3rd gears, Punching it NEVER Bogs/spits or nothing Runs like a Champ when ur trying to take off like ur in a race going for 1st,

thx for the Tip, ill try some reg plugs and see how it goes... What do the bosch 4 plugs do that is so bad? Jw

Thanks guys for the firing order, I had wired the engine totally backwards thinking 135 were on the front, fired right up after i corrected this


What is this i unplugged, didnt make a difference in revving, JW


What is this plastic hose that runs along the main harness into the cabin? the L shaped connector is falling apart

[TGP37]

Worth testing the fuel pressure, especially when running lean. Fuel pumps can weaken and provide low pressure, the pcm makes up the difference by increasing the IPW when the O2 sensor reads a lean burn. Though it wont adjust when cold, open loop.

Top pic is the intake air temp sensor
Bottom pic is the vacuum line to the heater/ac vent control box thing. If that is leaking air into the intake, you are feeding the engine unmetered air. That is a vacuum leak for sure.

The "T" leads to a vacuum reserve sphere tucked under the driver wheel area (at least thats where mine is). It has a check valve so there is vacuum available for the heater vent controls at open throttle.

Make that air tight and check the rest. It is very important no air enters the intake other then through the MAF onto the throttle body. But you probably know that.

Hope that helps


EDIT: In fact, if you really do have a vac leak there, I'm willing to bet sealing that will resolve all the engine issues, just like that. A friend of mine had a terrible idle and other issues with just a crack leaking air. If you cut the line and seal it, you will just loose all vents except for the windshield defrost. But it wont effect engine operation so long as it is sealed to the manifold.

[bigboi407]

Worth testing the fuel pressure, especially when running lean. Fuel pumps can weaken and provide low pressure, the pcm makes up the difference by increasing the IPW when the O2 sensor reads a lean burn. Though it wont adjust when cold, open loop.

Top pic is the intake air temp sensor
Bottom pic is the vacuum line to the heater/ac vent control box thing. If that is leaking air into the intake, you are feeding the engine unmetered air. That is a vacuum leak for sure.

The "T" leads to a vacuum reserve sphere tucked under the driver wheel area (at least thats where mine is). It has a check valve so there is vacuum available for the heater vent controls at open throttle.

Make that air tight and check the rest. It is very important no air enters the intake other then through the MAF onto the throttle body. But you probably know that.

Hope that helps


EDIT: In fact, if you really do have a vac leak there, I'm willing to bet sealing that will resolve all the engine issues, just like that. A friend of mine had a terrible idle and other issues with just a crack leaking air. If you cut the line and seal it, you will just loose all vents except for the windshield defrost. But it wont effect engine operation so long as it is sealed to the manifold.

its throwing a code for Cylinder 1 misfire now..... i bought the Delco plugs and am gonna put em in today ive gotten damn good ad getting the rear plugs with ease, as much as ive had to mess with these wires n plugs lol...

Its also bogging ALOT worse now, and the car has LESS power than before...... The guy @ AZ said i should try the coils, what do i need to test them? and where to i stick the leads, regular multimeter works for this? i got a few of those.... they also do not have a fuel pressure guage i can rent, but its $25 to buy it.....

I did notice the fuel pressure regulator has a screen on it on AZ website, does the Stock one have this, and since the original fuel filter was spitting dirty gas, so could it have clogged the regulator and injectors, You guys keep saying fuel pump, i may start leaning towards that choice myself, But am not sure, is there Anyone in the orlando Area that could help me out with determining whats wrong? i am all out of ideas, There is a fuel pump on ebay Brand new in package for $50 shipped, The Same pump my relative has for $105 on his site, and AZ has a pump that looks Very similar if not the same for $267................ i have bought a pump for a blazer from this ebay source and it worked fine got rid of that car so it was working when it went, im tellin her lets buy the $50 unit, any objections?

the car Barely wants to go now and is wasting a crap ton of gas..... i mean 43 miles or so ate 1/3 tank or more

EDIT: I have disconnected the MAP sensor and there is 0 running difference, Now the Code for MAP sensor pops up BUT it Does the Same exact things when it was plugged in.... Is that the problem? AZ guy says if i disconnected MAP sensor and its running the same then thats what the problem is because the MAP makes a huge difference

[TGP37]

You said something about a broken line that taps directly above Cyl 2's intake runner. You got a misfire for Cyl 1. Did you cap that vacuum port yet?

You are probably getting a lean misfire from the vac leak. If it were a fuel pump issue the misfire would be across all cylinders. The misfire happens to dump a lot of fresh oxygen into the exhaust. The O2 sensor detects and thinks the car is running lean, so it adds more fuel. So it's going to waste fuel when it misfires. MPG will return when the misfires stop, usually.

Do not under estimate a very small vacuum leak in the system. They can wreck havoc on the systems sensors to properly run the engine. You gotta scan all the vacuum lines, especially the one that is near the alternator. Find the MAF sensor and make sure the intake is sealed tight at every point after.

And try swapping the coils around and see if the misfire follows the coil.

Same with spark plug wires too. If you have a multi meter, check their resistance because they can break but they will still fire at idle.

You may have more then 1 issue to fix. Try this to ghetto test the fuel pump. After the car has sat for a bit, place your head just under the car by the fuel tank. Have a friend turn the key to on but don't start it. You will hear the pump prime up. You will be able to hear the pressure build in the lines as the pump noise curves with it. If you hear any grinding or other ill noise, anything that is inconsistant, is likely the pump is bad. If it sounds clean and strong, it's probably good.

[bigboi407]

You said something about a broken line that taps directly above Cyl 2's intake runner. You got a misfire for Cyl 1. Did you cap that vacuum port yet?

You are probably getting a lean misfire from the vac leak. If it were a fuel pump issue the misfire would be across all cylinders. The misfire happens to dump a lot of fresh oxygen into the exhaust. The O2 sensor detects and thinks the car is running lean, so it adds more fuel. So it's going to waste fuel when it misfires. MPG will return when the misfires stop, usually.

Do not under estimate a very small vacuum leak in the system. They can wreck havoc on the systems sensors to properly run the engine. You gotta scan all the vacuum lines, especially the one that is near the alternator. Find the MAF sensor and make sure the intake is sealed tight at every point after.

And try swapping the coils around and see if the misfire follows the coil.

Same with spark plug wires too. If you have a multi meter, check their resistance because they can break but they will still fire at idle.

You may have more then 1 issue to fix. Try this to ghetto test the fuel pump. After the car has sat for a bit, place your head just under the car by the fuel tank. Have a friend turn the key to on but don't start it. You will hear the pump prime up. You will be able to hear the pressure build in the lines as the pump noise curves with it. If you hear any grinding or other ill noise, anything that is inconsistant, is likely the pump is bad. If it sounds clean and strong, it's probably good.

what about me disconnecting the map sensor, its still runnin the same, Per AZ's Website:

"When not replaced, vehicle may run rich/lean, experience pinging, excessive hydrocarbons in oil causing engine bearing wear, spark plug fouling, catalytic converter failure, poor fuel economy, inconsistent transmission shift and/or CEL illumination"

Whats Pinging? i also did change her oil and it was excessively dark, but no code has shown for fail MAP

[TGP37]

If you have a nasty vac leak, you will have very little vacuum at all. So disconnecting the MAP will do little to change the problem.

Try to keep it simple. Fuel - Spark - Air - Compression

One of those is your problem area. Since you have a single misfire issue, it is reasonable to rule out things that would effect all 6 cylinders, like a bad MAP sensor.

Focus on Cyl 1, since that is the offending cyl. If it was the coil, I think both 1 and 4 would misfire often. Check the plug, cable, look around the head for signs of a leak. Cyl 1 is the rear one passanger side.

1 3 5
2 4 6
front

Did you seal the vacuum line that routes to the upper intake manifold, near the alternator? Just to test it, use duct tape if you have to until you can get a better line