InsomZ

iTrader: (1)

ok after 7 hours w/ alot of help from 2 of my friends.. the long tubes are installed.. y-pipe is on.. everything is bolted up tight.

car runs like crap now though.. seems slower then before.. also every single time i had to roll out from a light tonight.. car bogs, rattles(i assume the y-pipe), and rpms build up to normal..

I had the car LS1 edit dyno tuned by MTi before the headers.. i think they removed all the EGR checks..

2 things i think it might be..
rear '02 sensors are plugged in.. these are race style headers.. so the plug right there the cats use to be.
the front '02 sensors are not plugged in.. their just zip tied up. Or..

that the Y-pipe where it meets the header is right against the bottom of there car.. its just the way the headers hang.. their right up against the car almost touching.. maybe vibration causing a false knock? what would be good to put in there to keep it from rattling?

car does throw a Service engine soon light.

99Z28RS

I had mine installed last week and i definately noticed a big increase in power. i had banging problems too but i had a custom y made but i fixed the banging. As far as loss of power i know my car at WOT was showing very little knock and i was running slightly rich, Ltrims were good and everything was basically fine, were going to dyno tune it after my gear install and im sure i picked up atleast 20-25 Hp with the LT's and !cats.

SSEUL8R

check my post on this same subject. Im not quite sure what you did with your o2 sensors, but you need to get extensions and plug the front sensors that came out of your old manifolds into the collectors of your headers, and you need to get sims and plug them in the place of the 2 rear o2 sensors in the y-pipe.

jamnut

iTrader: (4)

If I'm reading this right you don't have your front 02's reading your exhaust?? If that's the case I would think that's 100% of your problem. Worry about the false knock after you get your 02's working.

TWISTA TA

I agree your front o2's are the problem. The reason why your car is running like that is because the o2's are telling you car to run REALLY RICH. You need to get the o2 simulators. Two sets will cost you about $180. You cant have the o2's plugged in and just hanging there. You can also use ls1 edit and delet the 02's. When you diagnose it you will see that your car is running way too rich from the confusment of the o2's.

ShadowLightCSU

iTrader: (1)

You totally need those front O2s, that's how your car knows to adjust your air/fuel mixture. Definitely 100% of your problem.

I've never heard of plugging o2 simms in the front either.

Scoggin Dickey

iTrader: (34)

They pretty much said it all. With the purchase of a long tube header, you need O2 sensor extensions so that your front O2 wires can reach and be functional. Most people are running O2 simulators for the rear O2's to keep from throwing the SES light that occurs when running an Off-road Y-pipe.

jamnut

iTrader: (4)

Your Pacesetters should have come with some wire, shrink wrap & wire crimps. That stuff is to extend your front O2 Leads so you can run your front O2 sensors.

MadIceV8

iTrader: (12)

Yea your O2's are the first problem. With mine I have an exhaust leak on either the headers or EGR/AIR tubes since some smoke is coming out of my engine bay and mine won't idle for longer then 2mins. I have yet to drive it, but when I reved it seemed to lose power. Damn leaks

Dave Carney

you didn't plug in the front o2's....you should delete this thread, change your user name, and pray for forgiveness.

SSEUL8R

I'd like to find out the hard way

Goober

LMAO

BAD ASS TA WS6

iTrader: (5)

Horrible advice, don't listen to it. DO NOT run O2 sims up front, you want them in the rear only. The front sims do all the real work, running sims up there is the last thing you want. Pay 90 for the rear sims and zip tie them up, then plug in your front 02s. This will fix your problem indefinately.

Rob

The Guy in MY 99TA

I'm suprised the car will run at ALL without the front o2's hooked up.

Jamnut..... I didn't know you were a member over at this board too!

Josh S.

jrp

iTrader: (16)

:yup: the pcm reads off the front o2's when in closed loop and that how it gauges your a/f ratio. sad when such bad info is going around


i knew exactly that was his problem the minute i read that line.

ShadowLightCSU

iTrader: (1)

I hope the two pairs of O2 simms was a joke

strippedls1

iTrader: (4)

Why are people telling him to get 02 simms, he had his car tuned by MTI, if they didnt already remove those rear 02 sensor checks from the computer they certainly should with no extra charge I would think. Either way yes the front 02 sensors must be plugged in and reading the exhaust stream or the car will not run worth a crap. If I paid for an MTI tune I damn sure wouldnt be buying 02 simms to remove something they could remove with a few keystrokes.

onyxxtreme

iTrader: (4)

exactly, strippedLS1
take the PCM to MTI and have them turn off the REAR O2's
plug your fronts back in the headers (with O2 extensions or extend your own)
then you'll be fine.
without your front O2 sensors the computer is in "autistic mode"

InsomZ

iTrader: (1)

problems fixed, SES lights off.. just had to use pacesetters ghetto 'extension kit' its litterly 1 thing of wire wrapped up, some wire chrimps, and wire cover.

other then the y-pipe banging i think its runnin alot better. sorry for the dumb question, appreciate the help.

99-LS1-SS

Remember there are no stupid questions just stupid people who ask them. Just kidding! To me it wasn't a dumb question because I learned also. I didn't know that the front O2 sensors where so important. Now knowing that I went ahead and ordered the O2 extensions with my headers. Thanks for taking the heat for someone else.