Pesky SES Light and Weak Car
02-17-2006, 04:12 PM
#22
did they replace the front 02's?this could have a huge effect on performance.another thing if the cats were changed before then i would strongly suggest you have the injectors checked for leaking.
Last edited by YoMommasTA; 02-17-2006 at 04:18 PM.
02-17-2006, 04:43 PM
#24
Originally Posted by Charging TA
Wow, after reading the first post my reply was going to be to check the Cats, they cause alot of weird problems... But glad the problem is solved.
02-17-2006, 05:07 PM
#27
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Originally Posted by YoMommasTA
please explain this.how could a cat effect engine performance?
02-17-2006, 05:49 PM
#30
Originally Posted by YokoLS1
Hi guys. I post on LS2 but I've been told the technical information is better here. I have a 2000 Trans Am M6 with 70,000 miles. It's completely stock. I have owned it almost 5 years with little trouble and it is babied. Sorry this is so long, but this is a long story. I'd appreciate any help.
I have had an SES light problem for the last 4 months. I've had misfire codes but my main problem has been oxygen sensors. P0137 and P0157. All oxygen sensors have been replaced.
The car feels weak as hell and according to 3 different mechanics, the oxygen sensors are "working just fine."
I am convinced there is some other problem that is causing these codes as a byproduct but their relationship is spurious. I don't think O2 sensors are my "real" problem. The light comes on at high RPM (5000-5500) and at full throttle.
The engine feels weak and hesitant at lower RPM especially as if it isn't getting enough gas.
It has been to a GM dealership 6 different times (mostly because I'm under extended warranty) and an independent ASE mechanic 5 or 6 times as well.
Here is what has been done:
Injector Flush.
Spark plugs and wires.
Throttle Body Cleaning.
All O2 sensors replaced.
AIR sensors. (not sure if this is the correct terminology)
Replaced PCM.
Replaced Cats under warranty as well.
All other obvious odds and ends.
Fuel pressure is good and the injectors appear to be getting enough fuel to the engine. There are no leaks in the intake or any vacuum leaks.
Even after the plugs and wires, I had a flashing SES light and cylinder 3 and 4 misfired almost 20,000 times between the 2 cylinders. Cylinders 7-8 did as well but not as bad. The plugs and wires are brand new and the work has been checked and rechecked. Coils are fine as well. Misfires don't seem to be an issue anymore. That was just a weird experience.
Despite all this work, the car has stumped 2 dealerships (not surprising) and one good mechanic who I trust. The O2 sensor wires don't appear to be compromised or anything of that sort. Everything has been triple checked. Basically, GM has told me they don't know what to do now and they have been through their infallible "flow chart."
For some reason, they want to "duplicate the problem" as if a mechanic driving my car and seeing for himself that the light comes on will tell them anything. It's just going to be the same old codes and they same old problem. They keep giving me the car back saying "it's fine" and it is nothing short of frustrating. If they can't get the light to come on themselves, they act like there's not a problem.
I wish I had some of you guys looking at my car instead of these imbeciles...
My next step will be taking it to an LS1 shop, I suppose.
Thanks for your input.
I have had an SES light problem for the last 4 months. I've had misfire codes but my main problem has been oxygen sensors. P0137 and P0157. All oxygen sensors have been replaced.
The car feels weak as hell and according to 3 different mechanics, the oxygen sensors are "working just fine."
I am convinced there is some other problem that is causing these codes as a byproduct but their relationship is spurious. I don't think O2 sensors are my "real" problem. The light comes on at high RPM (5000-5500) and at full throttle.
The engine feels weak and hesitant at lower RPM especially as if it isn't getting enough gas.
It has been to a GM dealership 6 different times (mostly because I'm under extended warranty) and an independent ASE mechanic 5 or 6 times as well.
Here is what has been done:
Injector Flush.
Spark plugs and wires.
Throttle Body Cleaning.
All O2 sensors replaced.
AIR sensors. (not sure if this is the correct terminology)
Replaced PCM.
Replaced Cats under warranty as well.
All other obvious odds and ends.
Fuel pressure is good and the injectors appear to be getting enough fuel to the engine. There are no leaks in the intake or any vacuum leaks.
Even after the plugs and wires, I had a flashing SES light and cylinder 3 and 4 misfired almost 20,000 times between the 2 cylinders. Cylinders 7-8 did as well but not as bad. The plugs and wires are brand new and the work has been checked and rechecked. Coils are fine as well. Misfires don't seem to be an issue anymore. That was just a weird experience.
Despite all this work, the car has stumped 2 dealerships (not surprising) and one good mechanic who I trust. The O2 sensor wires don't appear to be compromised or anything of that sort. Everything has been triple checked. Basically, GM has told me they don't know what to do now and they have been through their infallible "flow chart."
For some reason, they want to "duplicate the problem" as if a mechanic driving my car and seeing for himself that the light comes on will tell them anything. It's just going to be the same old codes and they same old problem. They keep giving me the car back saying "it's fine" and it is nothing short of frustrating. If they can't get the light to come on themselves, they act like there's not a problem.
I wish I had some of you guys looking at my car instead of these imbeciles...
My next step will be taking it to an LS1 shop, I suppose.
Thanks for your input.
02-18-2006, 03:09 AM
#31
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Originally Posted by YoMommasTA
this is my question to you,ALL this was caused by a clogged cat?because a cat could cause no other trouble EXCEPT a MIL.the fact that it runs good now seems to make sense that the cat was clogged.if the cat was just down on efficiency then it doesn't make sense.they should be able to explain how they tested for this and what they did.you can measure the bk pressure @ frt 02's to see if the cats are clogged.i seriously doubt you could drive the car with a clogged cat.it would barely run.
02-18-2006, 02:27 PM
#33
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Originally Posted by YoMommasTA
i've replaced many many clogged cats,thats why i question this repair.hoping this guy doesn't get ripped off by the dealer.
they won the battle.........this time..... 
02-19-2006, 02:43 AM
#37
TECH Senior Member
He can get an exhaust pressure gauge and measure exhaust back pressure in the front O2 sensor position; if it's greater than 3 or 4 psi, then the cat's blocked; would have to check both sides; simple enough test, would eliminate any doubts.
And checking his LTFT's would also give some insight.
Oh, wait, he said it was a blocked cat, and it got fixed under warranty...
You're right though, what caused the cat to get blocked...?
And checking his LTFT's would also give some insight.
Oh, wait, he said it was a blocked cat, and it got fixed under warranty...
You're right though, what caused the cat to get blocked...?
