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bmwm5lover
08-03-2003, 08:25 PM
Can someone clear up what it means to be running Rich, and what it means to be running lean. How can i tell(smoke, etc?), and which one is good, and bad? Im totally confusing my self! tahnx in advance.

Jon@Bimmersport
08-03-2003, 08:41 PM
rich - more gas than normal
lean - less gas than normal

bmwm5lover
08-03-2003, 09:39 PM
Originally posted by E46_lover
rich - more gas than normal
lean - less gas than normal
ok, that i had right in my mind, but, what would cause a car to run lean/rich, and how would i know which one my car is running?

Gamite
08-03-2003, 11:49 PM
u can usually tell if its running rich by the smell of the exhaust..

bmwm5lover
08-04-2003, 12:41 AM
whats it smell like?

Gamite
08-04-2003, 01:54 AM
I think if its really bad, it smells like rotten eggs.

bmwm5lover
08-04-2003, 02:14 AM
ok, mine doesnt smell like that. i think it smells the way its supposed to.

Gamite
08-04-2003, 02:50 AM
just start the car, get a chair, and sit behind the exhaust till you pass out.. if you pass out before 5 mins, then chances are you are running slightly rich.

lol :P

bmwm5lover
08-04-2003, 02:59 AM
Originally posted by Gamite
just start the car, get a chair, and sit behind the exhaust till you pass out.. if you pass out before 5 mins, then chances are you are running slightly rich.

lol :P
hahahha, i'd LOVE to give that a try! :D

Gamite
08-04-2003, 03:02 AM
just tell me when you do it, so I can steal your car after you pass out

bmwm5lover
08-04-2003, 03:03 AM
Originally posted by Gamite
just tell me when you do it, so I can steal your car after you pass out
Hahahha, sure thing!

Shamis
08-04-2003, 03:41 AM
hahahaha that means if ur runnin rich after 4 min ull be really really high

Jon@Bimmersport
08-04-2003, 03:18 PM
you can be running rich by your ECU config...you can set it to give u more or less gas....if u change the chip and add say a mark D or Jim C chip it will change the fuel mapping settings

bmwm5lover
08-04-2003, 11:55 PM
nop, its not that, apparently im leaking fuel like MAD!

Lennon
08-05-2003, 12:40 AM
I suggest you get that fixed, I don't think thats a good thing dude

bmwm5lover
08-05-2003, 12:52 AM
i just went to take a look at it, and i came to the verdict that its the fuel filter which probably cracked when i filled up today, since it was REALLY old, OR it could be one of the clamps connecting the fuel filter with a hose...

Autotechnica
08-06-2003, 03:53 AM
If it's rich, it doesn't smell like rotten eggs (that's something else). It should just smell like gasoline. Basically if it's rich that means too much gas and not enough air in the air/fuel mixture, if it's lean that means too much air and not enough gas in the mixture. Basically, running rich is OK. It's safer. Emissions will be high, fuel economy will be shit, that's about it. But by running lean you could seriously damage your engine (valvetrain).

Exhaust smell isn't the best way of tuning your A/F ratio. People used to do this on older cars w/ no O2/Oxygen sensors. You should have it checked profesionally at a dealer or car shop.

Bryan

Gamite
08-06-2003, 03:56 AM
o wait, maybe rotten eggs is your cat. or your ass.

bmwm5lover
08-06-2003, 03:59 AM
Originally posted by Autotechnica
If it's rich, it doesn't smell like rotten eggs (that's something else). It should just smell like gasoline. Basically if it's rich that means too much gas and not enough air in the air/fuel mixture, if it's lean that means too much air and not enough gas in the mixture. Basically, running rich is OK. It's safer. Emissions will be high, fuel economy will be shit, that's about it. But by running lean you could seriously damage your engine (valvetrain).

Exhaust smell isn't the best way of tuning your A/F ratio. People used to do this on older cars w/ no O2/Oxygen sensors. You should have it checked profesionally at a dealer or car shop.

Bryan
Bry, i think i might be running rich then , cuz im getting SHITTY gas mileage! about 350 on a full tank of gas, and i think i should be getting about 400+ (an di havent been driving like a maniac either, ive actually tried to concerve gas). Next time, at the meet, can you please smell mu exhaust fumes, and tell me what it smell s like. i cant really come up with a verdict?

Autotechnica
08-06-2003, 04:02 AM
Originally posted by Gamite
o wait, maybe rotten eggs is your cat. or your ass.

Good one *th-up*

Your are right, if it has a rotten egg smell (Sulfur), it's most likely the cats. However, it could also be that the gasoline your using contains a lot of surfur. It would then be recommended that you try switching to a higher octane gasoline.

Bry

Autotechnica
08-06-2003, 04:06 AM
Originally posted by bmwm5lover
Bry, i think i might be running rich then , cuz im getting SHITTY gas mileage! about 350 on a full tank of gas, and i think i should be getting about 400+ (an di havent been driving like a maniac either, ive actually tried to concerve gas). Next time, at the meet, can you please smell mu exhaust fumes, and tell me what it smell s like. i cant really come up with a verdict?

I'll have to charge you. Smelling your exhaust will take years off the end of my life :P :D

Bry

bmwm5lover
08-06-2003, 04:07 AM
Originally posted by Autotechnica
I'll have to charge you. Smelling your exhaust will take years off the end of my life :P :D

Bry
hahahhahah! Fine, ive got a dollar waiting for ya!*th-up*

Autotechnica
08-06-2003, 04:10 AM
I don't know anything about the M20's is it? Anyways, does it have an O2 sensor? Is your "Check Engine" light on? If so, you may want to get the fault codes read and see what may be malfunctioning.

Fuel filter replacement will not solve your fuel leaking problem. I've replaced mine on my own and unless it's punctured it shouldn't be related. However, check to see that your fuel lines aren't leaking or that they are properly clamped onto the fuel filter.

Bry

bmwm5lover
08-06-2003, 04:12 AM
Originally posted by Autotechnica
I don't know anything about the M20's is it? Anyways, does it have an O2 sensor? Is your "Check Engine" light on? If so, you may want to get the fault codes read and see what may be malfunctioning.

Fuel filter replacement will not solve your fuel leaking problem. I've replaced mine on my own and unless it's punctured it shouldn't be related. However, check to see that your fuel lines aren't leaking or that they are properly clamped onto the fuel filter.

Bry
yes the m20's have an 02 sensor, and they told me at BMW(when i went to pickup my filter) that lambda means my O2 sensor needs replacing. What i find strange is tho, the Engine light used to come on a lot, when i changed the air filter, it started coming on about half the time only, and now with the fuel filter, its even rarer, that it comes on...... go figure.....

Autotechnica
08-06-2003, 04:20 AM
Originally posted by bmwm5lover
yes the m20's have an 02 sensor, and they told me at BMW(when i went to pickup my filter) that lambda means my O2 sensor needs replacing. What i find strange is tho, the Engine light used to come on a lot, when i changed the air filter, it started coming on about half the time only, and now with the fuel filter, its even rarer, that it comes on...... go figure.....

I have no idea, but when I changed my intake, exhaust, throttle body using the stock chip I had check engine lights like no tomorrow. It always blinked on and off as I accelerated or bliped the throttle downshifting. However, when I installed my Dinan chip all those problems went away. BMW's computers have 2 settings, one is normal and the other is like a fail-safe, which to some extent will try to compensate for the extra air that your feeding into your engine.

I don't know if a K&N air filter will make enough of a difference. But usually when you add a mod that will affect your engine, your computer takes time to recalibrate itself to get use to the extra air/fuel intake.

Anyways, if your O2 sensor is bad, it's obviously causing all your problems.

Bry

bmwm5lover
08-06-2003, 04:31 AM
Do you think resetting the computer(by either unplugging the battery for 30 + minutes, or using theose tool thingies) will help?

Autotechnica
08-06-2003, 04:43 AM
Originally posted by bmwm5lover
Do you think resetting the computer(by either unplugging the battery for 30 + minutes, or using theose tool thingies) will help?

Not really. If your O2 sensor is faulty resetting the computer will give you the same results. But it never hurts to try.

disconnected the -ve battery terminal and wait at least 60 min, then reconnect it. That's it.

Bry

Bigbore
08-06-2003, 04:50 AM
if you are burning a lot of gas, and you can see a little black smoke if you gas it, then it may just be the timing, possibly your timing belt needs replacing? That is usually the first thing that gives you bad gas mileage, and if you say your O2 is gone then replace it, that also does the same..


ohhh, and running rich doesnt just damage your engine, it blows your engine up. Running rich you go slower and obviously burn more gas...

chrisp
08-11-2003, 06:00 PM
rich= ratio of gas:air has too much gas
lean= ratio of gas:air has too little gas

running rich uses more gas, you can get carbon deposits on your valves and pistons, you will CLOG your cat and leave black soot in your tailpipe

running lean gets better fuel economy, but too lean can lead to high temperatures on your valvetrain and burn your valves $$

if your O2 sensor is getting flaky, computer signals you with check engine light.. and then goes to 'closed loop' mode (ignores the o2 sensor)..

closed loop is generally a little rich (safe for engine but bad for cat).. you're better off too rich than too lean!

usually you run closed loop under WOT, which means those people with heavy feet will end up with a bit of soot in tailpipe (no big deal)

run too long with a dead o2 sensor and your cat gets clogged, power drops, gas mileage is horrible.. and time for new cat!

sulfur smell is from some gasolines burning off in your cat.. change gas brands

chrisP

bmwm5lover
08-11-2003, 06:03 PM
Thanx xhris, very informative!