Fuel Mixture adjustment?

I have a '96 SL-1 with 100K miles on it. The exhaust system was
replaced about 2 weeks ago and I noticed on the tailpipe alot of black
residue (carbon). Obviously the engine is running rich. How do I
adjust this?
Thanks,
Buster

 

Fuel mixture is controlled by the PCM and there is no user adjustment
provided to change it. There are several things that may cause it to feel
it needs to run rich. Have you had the codes read recently? That would
tell you if any pertinent sensors (intake temp, oxygen, engine temp) need
replacement or if any other problems exist. Has the car been getting worse
mileage? Also, if the dealer plugs into the car, he can see mixture over
time as well as real-time and confirm.

FYI, my tailpipes on my Saturns are always black. I'd tend to think that's
normal since I read my codes frequently and know everything is operating as
expected.

Lane [ l a n e @ p a i r . c o m ]

 

Yeah, I have a rolled, stainless exhaust tip that, and with a paper towel, I
wipe out the soot at car wash time. I didn't notice it as much with the old
OEM pipe.

 

You replace the Oxygen Sensor. If you have 100k miles on it, it's probably
past time.

 

You replace the Oxygen Sensor. If you have 100k miles on it, it's probably

I wouldn't replace a part like that just because........
My O2 sensor has more than 200k miles on it.

The black soot in the tailpipe is a common thing to every saturn I've seen.

 

Both my Saturns (SL-1's) have this also and started consuming oil around 80K
miles. I
suspect that the valve guide seals may be the cause. Check your spark plugs
to see if they show signs of excess oil being consumed.

 

I had an SES light several months ago. I bought a $40 code reader and
it was 1406. I replaced the EGR valve and cleared the code by
unhooking the battery for 20 minutes. The car ran like crap for a
while, got another code, then no problems. The only other thing I've
noticed is pinging under light accelleration (sometimes). Wouldn't
that be less likely with a rich condition?
Thanks,
Buster

 

Hi, Have had the service engine light on for a week now ( on and off,
mostly on) on the saturn SL2 96 ( 86K miles). Mileage dropped
significantly and there is lot of carbon on the tailpipe. Paid $50 to a
mechanic to learn that the computer generated a 1406 code. He blames the
problem on the use of low-garde gas. He is charging $400 to replace the
component. Does code 1406 mean EGR valve is malfunctioning and needs to be
replaced?
Any advice would be apprecited. thanks- Saturn_96

 

I searched Google for 'code 1406' and this came up. Maybe not directly
applicable but interesting.
http://www.asashop.org/autoinc/may2003/techtips.cfm

 

Try to clean EGR valve with carburetor cleaner using an old toothbrush to
remove the carbon. It is simple job that takes about 30 minutes. You also
need to get new EGR valve gasket. I hope this will help.
Michal

 

I have a sturn 94 SL1. Had similar problemm. My gas milieage was
extremely poor. Turns out it was my air temmperature sensor that wass
baddd therefor sending too much gas in the combustion chamber. Once
changed this was imeediately resolved. Might want to check this out.
There was also no codes given out by the car's system.. That's why I
was so surprised to know what was causing it. Hope this helps a little.

 

I have a '96 SL-1 with the same problem. Last year I got a 1406 code
so I replace the EGR valve and cleared the code by unhooking the
battery. It ran like crap (I assumed because I unhooked the battery
and lost the programming) for a while, then cleared up. About 2 days
later I got another 1406. Haven't had one for several months, now
that's it's cold, I've gotten two more. I will investigate the O2
sensor, but it looks like I'll have to go to someone with a real scan
tool.
Buster

 

The O2 sensors arent read until the car enters closed loop. If its cold,
it aint looking at it.

 

Ok, I guess that's $100 I don't have to spend right away. Any other
ideas on what could be causing this? My fuel consumption is off a
little, and I notice pinging under light accelleration (step on the
gas and the pinging quits). The pinging is an intermittent problem.
Car has 105k miles on it.
Thanks,
Buster

p.s. What exactly does 'closed loop' mean in this context?

 

Closed loop/open loop...It means the engine is either looking at all
your sensors to adjust itself or running from a default computer setting
for the current environmental conditions. O2 sensors and cat converters
dont work when their cold.

Pinging can be carbon, bad knock sensor, poor fuel or fuel delivery, or
a number of other things. It may ping when its cold but when it warms up
it should go away right? Dont try to correct this by going to a higher
octane gas. Thats a costly bandage to only fix a "symtom".

 

What is a knock sensor? Mine, now that it's colder here, is
somewhat acting like a wild broncho before it warms up. How much
does a knock sensor cost, roughly?