Hesitation = Bad pre cats Dealer diagnostic tells all(Read)
03-21-2005, 06:24 AM
#1
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Hesitation = Bad pre cats Dealer diagnostic tells all(Read)
Went to get my ecu reprogramed and also to have my timing advance to 17 degrees.Everybody here told me that with a new MAFS i had to have my ecu reprogrammed because my car was having hesitation after 4k rpm. The car could make it to redline but very slowly. Well after a few days with the new Am-600 MAFS went on my SES light went off, but i still had the hesistation. The day i decided to bring my car in for the reprogram the SES light came on. 
Well i knew i was going to have it out with the technicians , but when i got there the guy said if it was just the normal 02 codes that pop up, he will still go ahead with the reprogram of the ecu. Well the typical 02 sensor codes that everybody gets on this board didn't pop up. Come to find out my 02 sensors are fine , what was wrong was the pre-cats on the stock Y-pipe went bad! The first two pre cats went bad , the one that comes off the front manifold.My main cat and other pre cat are fine.
Because of the bad precats , its causing the engine to flood itself with fuel and starve itself with air which is causing major hesitation after 4k rpm.I asked the tech was this due to my intake being on the car, he said nope , its due to wear and tear and age of the stock y-pipe. He said he has suddenly had many Maximas come in for this problem especially Maximas that have about 50k t0 100k miles on them. (My car has 94k miles on it)
He told me that under his breath that the stock y-pipe w/precats are built cheap and is crap. The correct name for the stock -y-pipe by the way is called a Cattalist-spelling.
Price of a new stock y-pipe: $566 bucks, installing it:$255 bucks. Total pocket damage w/tax :$ 845 out the door.
So my conclusion to all of this: i am now forced to buy a aftermarket y-pipe.
So which one Berk or Cattman?
Also you guys with the phantom MAFS symptoms, think again.... it may not be your MAFS , coils, plugs, fuel pump,etc. Like the guy said, if your car can't get over 2500 rpm's then its your MAFS. No question about it. But if your car can get to 4k then basically struggle to redline its your pre cats that just crapped out on ya. He said this symptom usually happens on 2k2-2k3 Maxes, if you have a 2k0-2k1 , them its probally your VIAS. I hope this helps you guys with hesitation problems , hopefully this can lead you in the right direction instead of running around in the dark guessing WTF is going on with your MAX?
Symptoms of your pre-cats going out.Ok power to 4k rpm , then struggles to redline, terrible fuel milage drop, like mine, went from 25 city to 16.4 city and 27 highway to 18.0 highway.Loud raspy sound when under WOT. Sounds like the car is flying, but your standing still barely moving. If you have these symptoms and your driving a 2k2 or 2k3 Max then more then likely its your pre-cats that just crapped out on you.
Well i knew i was going to have it out with the technicians , but when i got there the guy said if it was just the normal 02 codes that pop up, he will still go ahead with the reprogram of the ecu. Well the typical 02 sensor codes that everybody gets on this board didn't pop up. Come to find out my 02 sensors are fine , what was wrong was the pre-cats on the stock Y-pipe went bad! The first two pre cats went bad , the one that comes off the front manifold.My main cat and other pre cat are fine.
Because of the bad precats , its causing the engine to flood itself with fuel and starve itself with air which is causing major hesitation after 4k rpm.I asked the tech was this due to my intake being on the car, he said nope , its due to wear and tear and age of the stock y-pipe. He said he has suddenly had many Maximas come in for this problem especially Maximas that have about 50k t0 100k miles on them. (My car has 94k miles on it)
He told me that under his breath that the stock y-pipe w/precats are built cheap and is crap. The correct name for the stock -y-pipe by the way is called a Cattalist-spelling.
Price of a new stock y-pipe: $566 bucks, installing it:$255 bucks. Total pocket damage w/tax :$ 845 out the door.
So my conclusion to all of this: i am now forced to buy a aftermarket y-pipe.
So which one Berk or Cattman?
Also you guys with the phantom MAFS symptoms, think again.... it may not be your MAFS , coils, plugs, fuel pump,etc. Like the guy said, if your car can't get over 2500 rpm's then its your MAFS. No question about it. But if your car can get to 4k then basically struggle to redline its your pre cats that just crapped out on ya. He said this symptom usually happens on 2k2-2k3 Maxes, if you have a 2k0-2k1 , them its probally your VIAS. I hope this helps you guys with hesitation problems , hopefully this can lead you in the right direction instead of running around in the dark guessing WTF is going on with your MAX?
Symptoms of your pre-cats going out.Ok power to 4k rpm , then struggles to redline, terrible fuel milage drop, like mine, went from 25 city to 16.4 city and 27 highway to 18.0 highway.Loud raspy sound when under WOT. Sounds like the car is flying, but your standing still barely moving. If you have these symptoms and your driving a 2k2 or 2k3 Max then more then likely its your pre-cats that just crapped out on you.
03-21-2005, 06:59 AM
#2
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Join Date: Apr 2003
Posts: 523
I thought the precats were on the exhaust manifold and not the y-pipe on the 5.5 gens.
03-21-2005, 07:06 AM
#3
Originally Posted by bgates1654
I thought the precats were on the exhaust manifold and not the y-pipe on the 5.5 gens.
That's what I thought too... that's the main reason why the 5th Gens get more gains with an aftermarket y-pipe than the 5.5s... the restrictions (pre-cats) are in the manifold and not the y-pipe...
If the pre-cats are truly fried, doesn't the emissions warranty cover them anyway?
03-21-2005, 07:09 AM
#4
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Originally Posted by Puppetmaster
That's what I thought too... that's the main reason why the 5th Gens get more gains with an aftermarket y-pipe than the 5.5s... the restrictions (pre-cats) are in the manifold and not the y-pipe...
If the pre-cats are truly fried, doesn't the emissions warranty cover them anyway?
Well the tech told me that the stock y-pipe with the precat section is bad.Theres a picture of the stock y-pipe somewhere on here. Hopefully someone will post this.
03-21-2005, 07:10 AM
#5
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Originally Posted by Puppetmaster
That's what I thought too... that's the main reason why the 5th Gens get more gains with an aftermarket y-pipe than the 5.5s... the restrictions (pre-cats) are in the manifold and not the y-pipe...
If the pre-cats are truly fried, doesn't the emissions warranty cover them anyway?
Yeah the emission warranty only goes 85k miles if i am not mistaken. I have 94k miles on mine.
03-21-2005, 07:18 AM
#6
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Go here http://maxima.theowensfamily.com/tsb...=2002&tsb=none
Then go to 02 sensor replacement. You have to have adobie acrobat, when the TSB comes up, scroll down to the 2002 section, the precat is after the manifold right after the flange. The the pipe runs into a bigger precat/precat group.
From the diagram it looks like the precats are part of the stock y-pipe not the manifold.
Then go to 02 sensor replacement. You have to have adobie acrobat, when the TSB comes up, scroll down to the 2002 section, the precat is after the manifold right after the flange. The the pipe runs into a bigger precat/precat group.
From the diagram it looks like the precats are part of the stock y-pipe not the manifold.
03-21-2005, 09:34 AM
#7
Originally Posted by Daily Driver2k2
Go here http://maxima.theowensfamily.com/tsb...=2002&tsb=none
Then go to 02 sensor replacement. You have to have adobie acrobat, when the TSB comes up, scroll down to the 2002 section, the precat is after the manifold right after the flange. The the pipe runs into a bigger precat/precat group.
From the diagram it looks like the precats are part of the stock y-pipe not the manifold.
Then go to 02 sensor replacement. You have to have adobie acrobat, when the TSB comes up, scroll down to the 2002 section, the precat is after the manifold right after the flange. The the pipe runs into a bigger precat/precat group.
From the diagram it looks like the precats are part of the stock y-pipe not the manifold.
wrong, the precats are integrated into the manifold. I have headers, thats the only way to remove the precats. Replacing the Y pipe on a 5.5 gen does absolutely nothing for melted precats. If you dont believe me, I will show you my stock manifold/precat the next time im in orlando. Any further posting on this subject will result in a one day.
edit: had you looked more closely, that is the diagram for a 2000 maxima.
03-21-2005, 09:43 AM
#8
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Join Date: May 2004
Posts: 6,190
I guess this is all the more reason to stick with a 4th Gen. The Budget y-pipe I bought took out the two OEM pre-cats.
WTF, how does someone with a 2002 car have 94K on it - sleep in it?
WTF, how does someone with a 2002 car have 94K on it - sleep in it?
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