Header Problem

**gmmastertech9825** · 09-17-2006, 09:26 AM

I Have A 99 Firebird And I Installed Dynatech Long Tube Heders On It With 3 Inch Collectors And 3 Inch Exaust To A Spin Tech Muffler I Have Removed The Cats And I Have O2 Sims For The Rear O2 Sensors. I Have O2 Extenders On The Front O2's. I Had To Remove My A.i.r. And E.g.r. To Install The Headers Because The Headers Don't Have The Connections. My Car Will Run Great One Day And The Next Runs Horrible It Idles At 400 Rpm And Stalls It Will Have A Quick Burst Of Accell By Itself At Times It Misses And Shakes Horribly I Have Dtc's For Misfire And Egr And Air Needless To Say I Need To Know What I Can Do To Fix This Problem Any Suggestions Are Appricated Thank You Very Much For Your Help.

**toofazt** · 09-17-2006, 09:38 AM

Sounds like you need a tune... Does it only do it when it's cold? BTW, how do you like the spintech muffler? Is it quiet?

**bene** · 09-17-2006, 09:42 AM

Check your plugs. I installed my longtubes 2 weeks ago, somehow I cracked 3 of them and didn't know about it even though I removed all of them before install. I had misfire and backfire.

**gmmastertech9825** · 09-17-2006, 10:14 AM

if i need a tune what should i tell the guy that will tune it should it be a dyno tune? and i love my spintech muffler it is quiet at idle and echoes through the city top end. i all ready put in new plugs and it does it when it is cold out and hot out. thank you for all you help

**2001NBMZ28** · 09-17-2006, 11:35 AM

Buddy of mine had a similar problem after his LT install. He had a plug wire arcing on #6 - we found it by starting the car in complete darkness and reving the engine. Something easy to try...

**gmmastertech9825** · 09-17-2006, 12:21 PM

ok i will try that thank you for the advice i will post what i find thanks

**sunsetorangess** · 09-17-2006, 03:04 PM

Yepp check your plugs and make sure your wires are tight and none of them have gotten burned.
J

**redline** · 09-18-2006, 07:06 PM

did you cap off the 1/4 in vacume hose on the driver rear of the motor. If you pulled the air pump out and all the plumbing to it then you should have pulled out a three way valve that has a little vac hose leading to the top of it. check that and front o2 sensors.

**gmmastertech9825** · 09-19-2006, 04:19 AM

thank you that is a excellent idea i will check that thanks again

**Roastem** · 09-19-2006, 06:06 AM

Check your plugs, then have it dyno-tuned. Then you won't need 02 simulators at all for the rear bank.

**gmmastertech9825** · 09-19-2006, 09:52 AM

please explain why i won't need rear o2 anymore and i don't remember the a.i.r. system being connected to a vacume source. any additional information will be appreciated thanks

**Roastem** · 09-19-2006, 10:58 AM

When you have it tuned, they can "teach" the computer to disregard the rear sensors, I don't know how exactly. They can do the same for the EGR. I don't have the rear 02's AT ALL or the EGR, only the plug-in remains, and I didn't get an SES light after tuning.

No cats either, lets keep that our little secret.

Also, the insulator on the spark plug can become cracked from small whacks from a "header flange" or not having the plug socket on there straight when you crank it tight. It will arc around the crack and reek all kinds of havoc on your engine. You will pull your hair out looking for sh*t if you ain't careful.

**toofazt** · 09-19-2006, 02:57 PM

Roastem, when you get a dyno tune they just delete the codes from your computer.

**Connexion2005** · 09-19-2006, 02:59 PM

Be sure the coil packs are connected fully and also double check your o2's. It's easy to accidently reverse them on the re-install (rear o2's ending up on the front) this cause horrible mpg btw.

**Roastem** · 09-20-2006, 04:27 AM

Originally Posted by toofazt

Roastem, when you get a dyno tune they just delete the codes from your computer.

Thanks for the info! Going to the tuner next Tuesday after Head/Meziere install.

**INMY01TA** · 09-20-2006, 03:14 PM

Originally Posted by Connexion2005

Be sure the coil packs are connected fully and also double check your o2's. It's easy to accidently reverse them on the re-install (rear o2's ending up on the front) this cause horrible mpg btw.

I always thought the front and rear ones were the same??

**Roastem** · 09-21-2006, 02:33 AM

Originally Posted by INMY01TA

I always thought the front and rear ones were the same??

Me too...

**MISFIT** · 09-21-2006, 03:17 AM

ok first of all, header installs require tuning, no matter what. its very possible to run very rich down low, and very lean up top....i wouldnt do to many high rpm runs until you know.

go to a tuner that has a dyno and uses LS1edit.....alot of places will say they can tune your car. they change plugs, wires, etc etc for $1,000, tell you your done, and the problem still exists. they dont really understand what you mean by a tune.... i had a shop try and pull that on me....after 5 minutes, i asked for my keys back and i drove away. they had my hoodup, and wrenches out.

all they should need is a laptop, an 02 bung connection, and a dyno if they are going to do it fast....stereet tune is alright, but you see the results on a dyno, and its much quicker and easier.

sounds to me like a loose plug wire.

btw, i thought you were a GM Master Tech?