rich mixture?
Thread Starter
Pro
Joined: Jan 2004
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From: Toronto ON
rich mixture?
It's time to get a smog test done and I'm a little hesitant. My car has all the pollution equipment in place but smells as if the catalytic converters aren't even there!
I checked the exhaust tips to find that there's definitely black soot all over (and on my fingers now, too!)
What do I do? Is there a way to lean out the mixture or to verify if it is rich. As you can see, I'm new to this (and the car is new to me).
Thanks. :confused:
I checked the exhaust tips to find that there's definitely black soot all over (and on my fingers now, too!)
What do I do? Is there a way to lean out the mixture or to verify if it is rich. As you can see, I'm new to this (and the car is new to me).
Thanks. :confused:
Le Mans Master
Joined: Feb 2002
Posts: 7,858
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Re: rich mixture? (Vett-eight-nine)
When posting mechanical questions be sure to indicate the year of your Corvette. New oxygen sensor(s) might help if it is making too much of the black carbon soot. Black on the inside of the pipes is normal, just not too much.
Drifting
Joined: Apr 2003
Posts: 1,292
Likes: 2
Re: rich mixture? (Vett-eight-nine)
I don't think you would get a code for an O2 sensor fault.
Change the sensor, and the engine temp sensor (on the block between cyls 1 and 3)
These are favorite for rich mixture faults.
Change the sensor, and the engine temp sensor (on the block between cyls 1 and 3)
These are favorite for rich mixture faults.
Intermediate
Joined: Oct 2003
Posts: 42
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From: San Lorenzo Ca
Re: rich mixture? (britvette)
"Change the sensor, and the engine temp sensor (on the block between cyls 1 and 3"........i thought that the coolant sensor that can cause a problem like that is located in the front of the engine under the throttle body? The one in between 1 and 3, isn't that just for the gauge inside the car?
Thread Starter
Pro
Joined: Jan 2004
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From: Toronto ON
Re: rich mixture? (89blkvet)
Yikes,I want to be aiming at the right thing (these parts are expensive). Any other opinions as to what I should be replacing, and where it's at?
Oh yeah, the EGR valve seem hidden under the plenum. Is that right? I have to remove the plenum to check it out, do you think? :eek:
Oh yeah, the EGR valve seem hidden under the plenum. Is that right? I have to remove the plenum to check it out, do you think? :eek:
Melting Slicks
Joined: Sep 2003
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From: 1,000,000,001 Posts
Re: rich mixture? (Vett-eight-nine)
Yes you have to take the plenum off to change out the ERG valve,, its not that bad of a job... One of the 2 nuts that is holding the egr to the intake is a pain in the butt to get to but it is possible.... I think it is a 8mm.... :cheers:
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Le Mans Master
Joined: Feb 2002
Posts: 7,858
Likes: 2
Re: rich mixture? (Vett-eight-nine)
EGR problem would likely cause a rough idle and some drivability problems, hesitation or stumble maybe. I would look at oxygen sensors and coolant temp sensor first. Faulty coolant temp sensor would be telling the ECM that the car is not warmed up enough to enter closed loop operation hence you would get a 'warm-up' fuel mixture 24/7. If I remember right one coolant temp sensor is a two wire sensor and that is the one to change-- its the one that is under the throttle body it provides coolant temp to to the digital LED or LCD temp readout on the dash/speedo and also to the ECM. The one wire coolant temp sensor which is in the head sends temp to the analog needle gauge. I am working off of LT1 layout, I cannot guarantee I am accurate on L98. Faulty oxygen sensor purportedly usually does not cause a code to be set. Good idea to change them every 50,000 miles as routeine tune-up and maintenance. Believe L98's have one oxygen sensor in front of the catalytic converter that would be the one to change. Again, I have an LT1 so that is what I am familiar with, someone with L98 hopefully will zero in on locations of these sensors on your car.
Thread Starter
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From: Toronto ON
Re: rich mixture? (Lone Ranger)
Thanks, guys.
Makes a lot of sense, Lone. I think I'll take a trip to the library and see if can find a Chilton manual or something. Anyone know the price of these parts (afraid to ask) :crazy:
Makes a lot of sense, Lone. I think I'll take a trip to the library and see if can find a Chilton manual or something. Anyone know the price of these parts (afraid to ask) :crazy:
Thread Starter
Pro
Joined: Jan 2004
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From: Toronto ON
Re: rich mixture? (1990CORVETTE)
Yes you have to take the plenum off to change out the ERG valve,, its not that bad of a job... One of the 2 nuts that is holding the egr to the intake is a pain in the butt to get to but it is possible.... I think it is a 8mm.... :cheers:
Thanks.
Drifting
Joined: Apr 2003
Posts: 1,292
Likes: 2
Re: rich mixture? (britvette)
I don't think you would get a code for an O2 sensor fault.
Change the sensor, and the engine temp sensor (on the block between cyls 1 and 3)
These are favorite for rich mixture faults.
Change the sensor, and the engine temp sensor (on the block between cyls 1 and 3)
These are favorite for rich mixture faults.
My advice still stands to change this sensor and the O2 sensor though.
Racer
Joined: May 2000
Posts: 322
Likes: 1
From: Manchester TN
Re: rich mixture? (Vett-eight-nine)
The single connector sensor is on the head between 8 and 6. You can see it in this picture:
According to my Haynes manual, this is the cooling fan switch. My fans only work when triggered by the AC. I have yet to find a parts store that carries this switch.
According to my Haynes manual, this is the cooling fan switch. My fans only work when triggered by the AC. I have yet to find a parts store that carries this switch.
Le Mans Master
Joined: Feb 2000
Posts: 9,715
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From: Kempner Texas
Re: rich mixture? (torque91)
There are three sensors that read coolant temperature.
One in each head (which accounts for two of them) and one in the front of the intake.
Now, GM flip-flopped the ones in the heads. On some years, the one in the driver's side head is for the dash gauge and the one in the passenger side head is for the fan.
On other years, like my 86, they are reversed. The one in the driver's side head is for the fan and the one in the passengers side head is for the dash gauge.
Doesn't really matter though, because the one you would change is the one in the front of the intake manifold, located to the left (passenger side) of the the thermostat housing. There are two side by side so change the correct one.
Jake
One in each head (which accounts for two of them) and one in the front of the intake.
Now, GM flip-flopped the ones in the heads. On some years, the one in the driver's side head is for the dash gauge and the one in the passenger side head is for the fan.
On other years, like my 86, they are reversed. The one in the driver's side head is for the fan and the one in the passengers side head is for the dash gauge.
Doesn't really matter though, because the one you would change is the one in the front of the intake manifold, located to the left (passenger side) of the the thermostat housing. There are two side by side so change the correct one.
Jake