2001 Buick Century 3.1 66k miles, Very sluggish

[bigboi407]

i drove about 30 miles or so then the car threw another CEL, i went to AZ, The car is throwing an EGR Code and MAP Code, I double checked the connections... both were just fine, i guess the map sensor really is the culprit, i will know once the new one comes in the mail

Well i went to a GM Dealer to buy a rubber 3 way peice that plugs unto the map sensor, i spoke with the guy there he said DEFF change the map sensor, he said that the map sensor can do a number of things INCLUDING not showing up, but now its throwing a code for MAP sensor and it has all day so We'll see once i change the sensor out

[talon2swords]

My 97 Lumina made a knocking noise and it would lose most all power in lower gear, like it was a major struggle to move. I didn't know what was wrong with it, but it turned out to be the infamous leaking LIM issue. There was no signs of water in the oil, and before I fixed it, I barely got it home via the interstate. It worked better at higher speeds, once I got past the lower gears. I guess the knock sensor w/ computer was trying its best to keep it going. Just my two cents.

[bigboi407]

gues what guys?? Same problems No more Codes.... parts arent here yet.... But W...T...Efff

[bluebird92]

Your car sounds exactly like my car did a few days ago. It had 0 power, and I was at wits end with it, so I sent it to a mechanic and he said somehow the egr was leaking atmospheric air into the intake. Also, to get it running, I replaced the fuel pump and filter, but the O-ring was defective and allowing fuel to escape, and when he replaced it, my car regained fuel pressure and ran fine. IMHO, if those are the codes, then by all means replace the MAP, and check your egr connections. And like TGP37 said, check your fuel pressure.

[bigboi407]

Guys i plugged Back in the MAP sensor, Cleared codes..... Drove to Downtown Orlando from deltona then to sanford and it wasted 1/2 tank of gas, Then it threw ANOTHER Code.... This time i have a MAP sensor Code #P0107 AND a EGR Code #P0404, The EGR is brand new, So the original may not even be bad..

guy at AZ Asked me if i can get the car to go over 60mph, i told em HELL NO!! and i told em how much gas i wasted and how the car has 0 power, hes like MOST DEFF has to be the MAP sensor... ive already ordered the MAP sensor and TPS just because they were Very cheap, i may tell her to get the fuel pump to keep it handy just incase it does go out,

The car Will not go in traffic, has 0 power... if i smash the gas from a stop i have power until i hit 2nd gear then the car TAKES FOREVER to pick up speed.... im hella aggrivated with this car, i appreciate ALL the help you guys have provided i have sprayed trhe engine bay with flammable sprays to see if i could find a leak, Nothing.... i dont know much of what else to do, i understand there has to be Air-Compression-Fuel-Spark but there is Something that im not used to or familiar with to blame for this, i hope to get this dealt with soon... once and for all

What kind of milage should she be seeing when the car is running in tip-top shape?

[bigboi407]

You might get you hands on a Big, Nasty Cigar.... Park the Car and with the hood up while it is idling light up the "Dog Rocket"... and without inhaling or keeping that awful smoke in your mouth, take a few huge puffs on the Stogie...and blow several of them as large clouds of over the front, back and sides of the engine compartment... if there is leak...the thick blue cigar smoke will trail down towards the leak and give a clear indication of where it is. This will not work on very windy days and don't forget to mind the lit end of the thing.... especially if there is an obvious odour of gasoline fuel vapours anywhere around the vehicle. Don't try this indoors, please...and for God's sake...when you find the vacuum leak...put that nasty thing out!

HELL NO..... Florida is never NOT windy and cigars are gross.....

I am very sure that vacuum hose is your problem IF it is allowing atmosphere air into the intake system. The amount of air entering the engine is more then what the mass air flow sensor is measuring. The engine only sprays enough fuel according to what the MAF says. That vac leak is causing havok....fix it.

You can spray small amounts of a flamable like staring fluid around suspected leak points. If there is a leak, the vacuum will draw in the gas and make the idle RPM increase.

i will Deff try this out, what if nothing happens? it only does this when in lower RPMs while in Drive, if i punch it, the engine revs up maxes out and the car doesnt go ANYWHERE, Old Ladys drive by us like GTFO THE WAY!!!!!

EDIT: 11am i have sprayed MAF Cleaner ALL over the engine bay and there was 0 difference in idle speed, i have yet to plug back in the MAP, found one on ebay for $30 and a TPS for $20 both including shipping.... they matchtch the same as AZ sells, same PN and both sellers have 99%+ feedback with thousands of sales

EDIT #2: Plugged the MAP back in, its still runnin like crap and i now have notcied a hissing sound AGAIN, But..... it will not happen in Park or Nuetral, SO W...T...Efff i got some good video of it acting up will be loaded soon

[60dgrzbelow0]

i forgot to mention that when it downshifts and revs up high engine starts pinging which i can provide video of, Also since im on the subject of Revving, When in Park it seems to have a Very low rev limit when revving but does not bog in park AT ALL, it doesnt have a RPM guage or id tell u what it is, but its most DEFF not as high as it does when it kicks down and pings,

What is the easiest way I can tell if there is a vacuum leak, a guy told meh to use a propane torch under the hood if the engine revs up theres a leak, but im not too sure of that idea

The TPS and MAP according to AZ's writeups says both of those can cause this problem i have but id like to confirm wether there is any vac leaks the process of elimination calls for something else to be done before i can buy anything new for it

i totally forgot about the hose

You might get you hands on a Big, Nasty Cigar.... Park the Car and with the hood up while it is idling light up the "Dog Rocket"... and without inhaling or keeping that awful smoke in your mouth, take a few huge puffs on the Stogie...and blow several of them as large clouds of over the front, back and sides of the engine compartment... if there is leak...the thick blue cigar smoke will trail down towards the leak and give a clear indication of where it is. This will not work on very windy days and don't forget to mind the lit end of the thing.... especially if there is an obvious odour of gasoline fuel vapours anywhere around the vehicle. Don't try this indoors, please...and for God's sake...when you find the vacuum leak...put that nasty thing out!

[TGP37]

I am very sure that vacuum hose is your problem IF it is allowing atmosphere air into the intake system. The amount of air entering the engine is more then what the mass air flow sensor is measuring. The engine only sprays enough fuel according to what the MAF says. That vac leak is causing havok....fix it.

You can spray small amounts of a flamable like staring fluid around suspected leak points. If there is a leak, the vacuum will draw in the gas and make the idle RPM increase.

[bigboi407]

i forgot to mention that when it downshifts and revs up high engine starts pinging which i can provide video of, Also since im on the subject of Revving, When in Park it seems to have a Very low rev limit when revving but does not bog in park AT ALL, it doesnt have a RPM guage or id tell u what it is, but its most DEFF not as high as it does when it kicks down and pings,

Whats the easiest way i can tell if theres a vacuum leack, a guy told meh to use a propane torch under the hood if the engine revs up theres a leak, but im not too sure of that idea

The TPS and MAP according to AZ's writeups says both of those can cause this problem i have but id like to confirm wether there is any vac leaks the process of elimination calls for something else to be done before i can buy anything new for it

i totally forgot about the hose

[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

[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]

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]

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]

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]

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