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Say no to surge

Switzersland

Switzersland

New member
I'm replacing my stock dp and cat on our 2000 Grand prix gt and I was hoping I could get a few suggestion from the crowd here on what to look for and where to shop for a dp & cat welded with 2.25 I/O. I'm replacing as was mentioned to me that the surge in power and the accelerator feathering I have to do to get it up to speed is due to a blocked cat.
 


zzp makes a 2.5in catted downpipe that will come in one peice and will bolt right up to the resonator and rear manifold. its a little bigger diameter of pipeing but it gets rid of the nasty u-bend
 


Hi Gang, I know it's been over a year. i just purchased the 304ss dp w-cat from zzp. Can i get some install tips as this will be a DIY. I've maintained my own vehicle since my 1974 Opel Manta Rally coupe.

The Gt still has the same problem with sluggish acceleration on cold mornings, the "EGG" odor is noticeable after a 18 mile commute and the service engine light come on seldom and goes off after a week . other than that the GT runs fine.

TGIF

L8TR
 
Jack the car up as high as you car. You'll need the room...

There are a total of 4 bolts you need to remove... 2 on each end of the flanges. (where it meets the cat-back, and where it meets the rear manifold)

Soak all 4 bolts with Rust Penetrant...like PB Blaster, or the like...and do it a few times...it'll make life easier.

Remove all 4 bolts, and the rear O2 sensor.

Put the new gaskets on, and slather them with some RTV....Then tighten down the bolts like all hell, put the O2sensor back in, and you're good.

It's kind of a PITA to get everything to line up well, but you'll get it after some swearing and hitting stuff.

And the sluggish acceleration/egg smell...that's a bad catalytic...replacing it with the DP you bought should fix that.
 
ok she's in and the only problem is the oem o2 sensor is too long (that's what she said. sorry, it's friday night). I had to cut some (minor) heat shield, however the stem on the o2 sensor is riding tight against the under body. Do I need to get a special zzp o2sensor? or would a new one from say auto zone fit?

Thanks again, cheers.

Ps No bogg, no egg , nice acceleration and kinda throaty now.
 
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ok after one day w/ new dp and cat from zzp-the sluggish take off still exists. plugs and fuel filter are not that old, however could need changed. any ideas? at 3000 rpm's at cold take off, only 15 mph and feathering accelerator.


WTF? over
 


I cleaned the MAF sensor and the spring loaded (pressure sensor???) to the feft of the MAF, along the intake manifold. This sensor has an orange "o" ring and was filthy full of carbon. I hope this does the trick. anyone know what the actual nomencalture of the spring loaded sensor?
 
The sensor you are thinking of is your IAC Valve (Idle Air Control)
And $60 is a safe bet for what you can get for the used cat, sometimes it is more sometimes less.
 
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