my alero stumbles bad
#1
10-04-2009, 07:29 PM
my alero stumbles bad
my car wants to lag really bad about 1 minute after driving from starting my car. i crank my car up everthing is fine i start driving everything is fine after a minute of driving my car goes from 0-10mph just find then stumbles to go from 10-30 and no power what so ever after 50 mph.
ive changed my fuel filter, sparkplugs, sparkwires, intake manifold gasket, transmission fluid, air filter, flushed and filled coolant.
everything i turn my car off and turn it back on it drives just fine for about 1-2mins than goes back to driving like crap
and no check engine lights are on
ive changed my fuel filter, sparkplugs, sparkwires, intake manifold gasket, transmission fluid, air filter, flushed and filled coolant.
everything i turn my car off and turn it back on it drives just fine for about 1-2mins than goes back to driving like crap
and no check engine lights are on
#2
10-04-2009, 07:32 PM
oh its a 2002 oldsmobile alero gls 3.4 i guess you can say the car is bogging down
Last edited by CrappyAleroGLS; 10-04-2009 at 08:29 PM.
#3
10-04-2009, 09:00 PM
Is it actually related to speed, or is it related to rpm? How's your mileage?
My bet is a plugged cat.
A partially plugged cat causes pressure to build up in the exhaust system. As pressure builds up, the engine loses power. The more pressure, the more power you lose. Eventually the engine won't stay running.
Since the cat isn't fully plugged, at idle, it may be flowing enough to work fine. As you work your way up the gears, pressure builds and the car falls on its face. Shut down the engine and the pressure bleeds down.
The kicker is, the plug can get worse as the cat heats up, which is why you don't really notice it on a fresh start up.
Other classic symptoms are a rattling noise in the exhaust, really bad gas mileage and a sweet (like burning marshmallows) or phosphorus smell.
My bet is a plugged cat.
A partially plugged cat causes pressure to build up in the exhaust system. As pressure builds up, the engine loses power. The more pressure, the more power you lose. Eventually the engine won't stay running.
Since the cat isn't fully plugged, at idle, it may be flowing enough to work fine. As you work your way up the gears, pressure builds and the car falls on its face. Shut down the engine and the pressure bleeds down.
The kicker is, the plug can get worse as the cat heats up, which is why you don't really notice it on a fresh start up.
Other classic symptoms are a rattling noise in the exhaust, really bad gas mileage and a sweet (like burning marshmallows) or phosphorus smell.
#4
10-04-2009, 10:02 PM
well i unplugged my mass air flow sensor and drove the car for about 10 mins and no check engine light came on and had the same exact symptoms just more severe. dragged like crazy ater 10mph and power comes back when it hits 30
#6
10-04-2009, 10:14 PM
Any shop can do a simple back pressure test. I would expect unplugging the MAF to make your symptoms worse, although a bad MAF can cause your problems.
Some people will remove the O2 sensor and drive a little bit. This will allow exhaust out and relieve back pressure if the cat is plugged. I am not recommending that you try it, however.
You may also check the fuel pressure at the rail, but I don't think a weak fuel pump is your problem.
Some people will remove the O2 sensor and drive a little bit. This will allow exhaust out and relieve back pressure if the cat is plugged. I am not recommending that you try it, however.
You may also check the fuel pressure at the rail, but I don't think a weak fuel pump is your problem.
#7
10-05-2009, 07:51 AM
cant i just dump some acid down my exhaust??? lol no???
but is it ok to drive the car with the oxygen sensor pulled out? im used to driving imports where the oxygen sensor next to the cat serves no purpose
but is it ok to drive the car with the oxygen sensor pulled out? im used to driving imports where the oxygen sensor next to the cat serves no purpose
#8
10-05-2009, 05:58 PM
well brought it to a muffler shop and they told me my cat was clogged pretty bad sooo..... im broke and have no way of paying for this 179.99 installed just recently got my intake manifold gasket changed and water pump and and a new coolant resivoir just like 2 weeks ago so yeah this sucks lol so i get a cat from a junk yard for a temp fix?
or would it hurt my car to just drive with the o2 sensor out for a little while intill i can come up with the money?
or would it hurt my car to just drive with the o2 sensor out for a little while intill i can come up with the money?
Last edited by CrappyAleroGLS; 10-05-2009 at 06:24 PM.
#9
10-05-2009, 08:24 PM
Do NOT drive for any length of time (more than 1 or 2 minutes) with the o2 sensor out. All that hot exhaust in the engine compartment could cause a fire, or it could get into the cabin and kill you from the fumes.
It is true that the o2 sensor after the cat is there only to monitor the emissions system function, it does not affect the operation of the engine.
You can get a junkyard cat but it'll cost you $ to have it installed, so in the end it might not be a real savings. I have heard of guys just drilling a few large holes in the cat to release the exhaust, but it makes the car noisy and is probably illegal as well, so I wouldn't recommend it.
It is true that the o2 sensor after the cat is there only to monitor the emissions system function, it does not affect the operation of the engine.
You can get a junkyard cat but it'll cost you $ to have it installed, so in the end it might not be a real savings. I have heard of guys just drilling a few large holes in the cat to release the exhaust, but it makes the car noisy and is probably illegal as well, so I wouldn't recommend it.
#10
10-06-2009, 07:21 AM
Just curious, how did the shop figure out it was the cat?
I don't know the exact config of the alero, but I do know OBDII cars have 2 O2 sensors. One is upstream from the cat and sits just behind the exhaust manifold and the other is just downstream from the cat. Signal from the upstream sensor is used in closed loop mode to tweak the a-f mixture (ie how much gas is squirted in), while the downstream sensor just makes sure the cat is working.
Point is, the only O2 you could pull that would help would be the upstream and that has pretty large consequences on engine operation. As a temporary solution, you can remove the cat and gut it (knock out the catalyst) then reinstall it. If you have to cut it out, clamp style connectors are cheap. The drawback to this is it will make the car loud, and some systems will detect the cat isn't working (with the downstream O2) and not allow the engine into closed loop (giving bad performance and mileage). You can sometimes get around this by pulling the downstream O2 out, zip tieing it to the frame (so it always reads clean air) and plugging the hole in the exhaust. However some systems will detect the O2 isn't staying hot and will again throw a code and stick in open loop.
I don't know the exact config of the alero, but I do know OBDII cars have 2 O2 sensors. One is upstream from the cat and sits just behind the exhaust manifold and the other is just downstream from the cat. Signal from the upstream sensor is used in closed loop mode to tweak the a-f mixture (ie how much gas is squirted in), while the downstream sensor just makes sure the cat is working.
Point is, the only O2 you could pull that would help would be the upstream and that has pretty large consequences on engine operation. As a temporary solution, you can remove the cat and gut it (knock out the catalyst) then reinstall it. If you have to cut it out, clamp style connectors are cheap. The drawback to this is it will make the car loud, and some systems will detect the cat isn't working (with the downstream O2) and not allow the engine into closed loop (giving bad performance and mileage). You can sometimes get around this by pulling the downstream O2 out, zip tieing it to the frame (so it always reads clean air) and plugging the hole in the exhaust. However some systems will detect the O2 isn't staying hot and will again throw a code and stick in open loop.