bowtieman81

iTrader: (35)

I put header and ory on my car not long ago and I am sure the thing is running to rich. My bud could smell it driving behind me, and in a small garage my eyes will start to sting. I know tuning will take care of that, I am just wondering why it runs so rich. I thought the factory tune could/should compensate for small mods that get more air into the engine. Or is it likely my relocated and/or bad O2 sensors?

01 Red WS6

iTrader: (4)

I think the smell is from having an ORY. the cat help with the smell

Keenov

iTrader: (5)

It's mainly because you took your cats off, as I see you are running an off road y-pipe. The cats were there to burn the excess gas and now they are not. I wouldn't be worried about it.

That is correct, but headers don't get air into the engine

pimpmaro

A good header should from the scavenging effect.

MeentSS02

iTrader: (11)

I thought I read somewhere that headers actually make your car run leaner. Because of that, the computer tries to compensate by dumping in extra fuel, making the LTrims positive. When you go WOT, and the LTrims are positive, it just dumps in fuel indiscriminately since it goes into open loop.

I probably have that all screwed up, but it makes sense to me.

bowtieman81

iTrader: (35)

Well, I did a couple logging runs at WOT and the O2 sensors were reading a rich condtion the whole way. That might make sense. I have been trying to figure out why it seems to be rich at idle too. Maybe I am idling in open loop for some reason (besides the open loop warm-up period). I will have to take a couple logs at idler and see. Thanks all.

MeentSS02

iTrader: (11)

I'll hopefully have my software soon so I can back you up on that...I know my car is running rich, just can't prove it.

DWillTA

iTrader: (3)

MeentSS02 is correct. Take a carb engine. If you put headers on it and do not rejet you will be lean and depending on your A/F ratio before hand you may be ok or in the danger zone. With a computer controlled car the computer try's to reset the fuel system based on sensor info. Yes if the ltrims are positive that means fuel is being added and you are lean to begin with. If negative then you are rich and fuel is being pulled. So depending on the state of the stock tune will depend if you will have to be mega enriched with fuel or just slightly enriched. I put headers on about 3 weeks ago. My Ltrims are in the +10 range at idle and WOT. I have very little odor. It was worse when I first did the install but now if I am running the car hard or in a lower gear and let the engine pull itself down it will have some odor. Hope that clears it up alittle.

jimmyblue

iTrader: (11)

There are two separate effects.

One is the exhaust extraction, improved scavenging cleans
out the cylinder leaving less spent (neutral) gasses and a
fresher charge on intake is the result. People used to say
headers leaned you out though I suspect this was really
more about pinging from a better charge, which burns
faster.

The other is, headers cool the exhaust gas more (surface
area) and locate the O2s further downstream. A cold O2
that went to sleep looks like a lean O2. So the PCM throws
fuel at the problem.

Camaro99SS

iTrader: (4)

Was it bad enough for the car to throw codes? My car seems to run a little rich as well from smell. I reused my o2's and don't throw codes, but mine smells like it is. It's not as bad as what you described, but cars I've been around without cats don't smell if they're in tune.

Jason