86 CJ7 Failed Emissions Test -- Help
10-21-2003, 03:00 PM
#1
Guest
Posts: n/a
86 CJ7 Failed Emissions Test -- Help
My 86 CJ7 failed Virginia's strict emissions test, I need advice on
how to get it to pass. I can do mechancial work myself if I know what
to tackle. Here are the specifics:
15 MPH Test 25 MPH Test
HC (Limit/Readings) 207/50 Pass 201/298 Fail
CO 1.76/.01 Pass 2.29/4.69 Fail
NO 3010/2192 Pass 2796/215 Pass
RPM 1926 Valid 1279 Valid
Dilution 14.9 Valid 16.8 Valid
Visual components and smoke inspections passed.
Thanks in advance for any hints you may be willing to offer. Dan
how to get it to pass. I can do mechancial work myself if I know what
to tackle. Here are the specifics:
15 MPH Test 25 MPH Test
HC (Limit/Readings) 207/50 Pass 201/298 Fail
CO 1.76/.01 Pass 2.29/4.69 Fail
NO 3010/2192 Pass 2796/215 Pass
RPM 1926 Valid 1279 Valid
Dilution 14.9 Valid 16.8 Valid
Visual components and smoke inspections passed.
Thanks in advance for any hints you may be willing to offer. Dan
10-21-2003, 03:31 PM
#2
Guest
Posts: n/a
Re: 86 CJ7 Failed Emissions Test -- Help
"Dan Grulke" <dwgrulke@mindspring.com> wrote in message
news:9be7d463.0310211100.6158f3ab@posting.google.c om...
> My 86 CJ7 failed Virginia's strict emissions test, I need advice on
> how to get it to pass. I can do mechancial work myself if I know what
> to tackle. Here are the specifics:
> 15 MPH Test 25 MPH Test
> HC (Limit/Readings) 207/50 Pass 201/298 Fail
> CO 1.76/.01 Pass 2.29/4.69 Fail
> NO 3010/2192 Pass 2796/215 Pass
> RPM 1926 Valid 1279 Valid
> Dilution 14.9 Valid 16.8 Valid
>
> Visual components and smoke inspections passed.
> Thanks in advance for any hints you may be willing to offer. Dan
Just found this on a website:
CRUISE EMISSIONS
At cruise, the engine is lightly loaded and running at high rpm. Under these
conditions, HC and CO should be low if the oxygen sensor and feed back
control system are working properly, and the catalytic converter is in good
condition.
High CO readings during cruise indicate a rich fuel condition. Causes here
may include:
.. Defective O2 sensor;
.. Exhaust leaks upstream of the O2 sensor (check manifold gaskets and air
plumbing connections);
.. Defective AIR pump or diverter valve (also loose or damaged air pump
plumbing);
.. Defective MAP, MAF or VAF sensor;
.. Float level and operation (older carbureted engines); and
.. Power valve operation (older carbureted engines).
High HC during cruise would indicate a steady misfire or loss of compression
(leaky exhaust valve).
This should give you some things to check for. Also, because it seems you
are running rich, check the air filter and choke for proper operation. I
would also check to make sure the EGR valve (if it has one) is functioning
properly.
Chris
10-21-2003, 03:31 PM
#3
Guest
Posts: n/a
Re: 86 CJ7 Failed Emissions Test -- Help
"Dan Grulke" <dwgrulke@mindspring.com> wrote in message
news:9be7d463.0310211100.6158f3ab@posting.google.c om...
> My 86 CJ7 failed Virginia's strict emissions test, I need advice on
> how to get it to pass. I can do mechancial work myself if I know what
> to tackle. Here are the specifics:
> 15 MPH Test 25 MPH Test
> HC (Limit/Readings) 207/50 Pass 201/298 Fail
> CO 1.76/.01 Pass 2.29/4.69 Fail
> NO 3010/2192 Pass 2796/215 Pass
> RPM 1926 Valid 1279 Valid
> Dilution 14.9 Valid 16.8 Valid
>
> Visual components and smoke inspections passed.
> Thanks in advance for any hints you may be willing to offer. Dan
Just found this on a website:
CRUISE EMISSIONS
At cruise, the engine is lightly loaded and running at high rpm. Under these
conditions, HC and CO should be low if the oxygen sensor and feed back
control system are working properly, and the catalytic converter is in good
condition.
High CO readings during cruise indicate a rich fuel condition. Causes here
may include:
.. Defective O2 sensor;
.. Exhaust leaks upstream of the O2 sensor (check manifold gaskets and air
plumbing connections);
.. Defective AIR pump or diverter valve (also loose or damaged air pump
plumbing);
.. Defective MAP, MAF or VAF sensor;
.. Float level and operation (older carbureted engines); and
.. Power valve operation (older carbureted engines).
High HC during cruise would indicate a steady misfire or loss of compression
(leaky exhaust valve).
This should give you some things to check for. Also, because it seems you
are running rich, check the air filter and choke for proper operation. I
would also check to make sure the EGR valve (if it has one) is functioning
properly.
Chris
10-21-2003, 03:31 PM
#4
Guest
Posts: n/a
Re: 86 CJ7 Failed Emissions Test -- Help
"Dan Grulke" <dwgrulke@mindspring.com> wrote in message
news:9be7d463.0310211100.6158f3ab@posting.google.c om...
> My 86 CJ7 failed Virginia's strict emissions test, I need advice on
> how to get it to pass. I can do mechancial work myself if I know what
> to tackle. Here are the specifics:
> 15 MPH Test 25 MPH Test
> HC (Limit/Readings) 207/50 Pass 201/298 Fail
> CO 1.76/.01 Pass 2.29/4.69 Fail
> NO 3010/2192 Pass 2796/215 Pass
> RPM 1926 Valid 1279 Valid
> Dilution 14.9 Valid 16.8 Valid
>
> Visual components and smoke inspections passed.
> Thanks in advance for any hints you may be willing to offer. Dan
Just found this on a website:
CRUISE EMISSIONS
At cruise, the engine is lightly loaded and running at high rpm. Under these
conditions, HC and CO should be low if the oxygen sensor and feed back
control system are working properly, and the catalytic converter is in good
condition.
High CO readings during cruise indicate a rich fuel condition. Causes here
may include:
.. Defective O2 sensor;
.. Exhaust leaks upstream of the O2 sensor (check manifold gaskets and air
plumbing connections);
.. Defective AIR pump or diverter valve (also loose or damaged air pump
plumbing);
.. Defective MAP, MAF or VAF sensor;
.. Float level and operation (older carbureted engines); and
.. Power valve operation (older carbureted engines).
High HC during cruise would indicate a steady misfire or loss of compression
(leaky exhaust valve).
This should give you some things to check for. Also, because it seems you
are running rich, check the air filter and choke for proper operation. I
would also check to make sure the EGR valve (if it has one) is functioning
properly.
Chris
10-21-2003, 03:40 PM
#5
Guest
Posts: n/a
Re: 86 CJ7 Failed Emissions Test -- Help
Hi Dan,
Do your normal tune up, Plugs, cap and ignition wires, maybe,
install a carburetor kit. Or install a new catalytic converter which
will burn the Hydrocarbons and change Carbon Monoxide into harmless
byproducts. My Bronco test: http://www.----------.com/smog.jpg It has
almost three hundred thousand miles on it, and the heads have never been
off.
God Bless America, ßill O|||||||O
mailto:-------------------- http://www.----------.com/
Dan Grulke wrote:
>
> My 86 CJ7 failed Virginia's strict emissions test, I need advice on
> how to get it to pass. I can do mechancial work myself if I know what
> to tackle. Here are the specifics:
> 15 MPH Test 25 MPH Test
> HC (Limit/Readings) 207/50 Pass 201/298 Fail
> CO 1.76/.01 Pass 2.29/4.69 Fail
> NO 3010/2192 Pass 2796/215 Pass
> RPM 1926 Valid 1279 Valid
> Dilution 14.9 Valid 16.8 Valid
>
> Visual components and smoke inspections passed.
> Thanks in advance for any hints you may be willing to offer. Dan
Do your normal tune up, Plugs, cap and ignition wires, maybe,
install a carburetor kit. Or install a new catalytic converter which
will burn the Hydrocarbons and change Carbon Monoxide into harmless
byproducts. My Bronco test: http://www.----------.com/smog.jpg It has
almost three hundred thousand miles on it, and the heads have never been
off.
God Bless America, ßill O|||||||O
mailto:-------------------- http://www.----------.com/
Dan Grulke wrote:
>
> My 86 CJ7 failed Virginia's strict emissions test, I need advice on
> how to get it to pass. I can do mechancial work myself if I know what
> to tackle. Here are the specifics:
> 15 MPH Test 25 MPH Test
> HC (Limit/Readings) 207/50 Pass 201/298 Fail
> CO 1.76/.01 Pass 2.29/4.69 Fail
> NO 3010/2192 Pass 2796/215 Pass
> RPM 1926 Valid 1279 Valid
> Dilution 14.9 Valid 16.8 Valid
>
> Visual components and smoke inspections passed.
> Thanks in advance for any hints you may be willing to offer. Dan
10-21-2003, 03:40 PM
#6
Guest
Posts: n/a
Re: 86 CJ7 Failed Emissions Test -- Help
Hi Dan,
Do your normal tune up, Plugs, cap and ignition wires, maybe,
install a carburetor kit. Or install a new catalytic converter which
will burn the Hydrocarbons and change Carbon Monoxide into harmless
byproducts. My Bronco test: http://www.----------.com/smog.jpg It has
almost three hundred thousand miles on it, and the heads have never been
off.
God Bless America, ßill O|||||||O
mailto:-------------------- http://www.----------.com/
Dan Grulke wrote:
>
> My 86 CJ7 failed Virginia's strict emissions test, I need advice on
> how to get it to pass. I can do mechancial work myself if I know what
> to tackle. Here are the specifics:
> 15 MPH Test 25 MPH Test
> HC (Limit/Readings) 207/50 Pass 201/298 Fail
> CO 1.76/.01 Pass 2.29/4.69 Fail
> NO 3010/2192 Pass 2796/215 Pass
> RPM 1926 Valid 1279 Valid
> Dilution 14.9 Valid 16.8 Valid
>
> Visual components and smoke inspections passed.
> Thanks in advance for any hints you may be willing to offer. Dan
Do your normal tune up, Plugs, cap and ignition wires, maybe,
install a carburetor kit. Or install a new catalytic converter which
will burn the Hydrocarbons and change Carbon Monoxide into harmless
byproducts. My Bronco test: http://www.----------.com/smog.jpg It has
almost three hundred thousand miles on it, and the heads have never been
off.
God Bless America, ßill O|||||||O
mailto:-------------------- http://www.----------.com/
Dan Grulke wrote:
>
> My 86 CJ7 failed Virginia's strict emissions test, I need advice on
> how to get it to pass. I can do mechancial work myself if I know what
> to tackle. Here are the specifics:
> 15 MPH Test 25 MPH Test
> HC (Limit/Readings) 207/50 Pass 201/298 Fail
> CO 1.76/.01 Pass 2.29/4.69 Fail
> NO 3010/2192 Pass 2796/215 Pass
> RPM 1926 Valid 1279 Valid
> Dilution 14.9 Valid 16.8 Valid
>
> Visual components and smoke inspections passed.
> Thanks in advance for any hints you may be willing to offer. Dan
10-21-2003, 03:40 PM
#7
Guest
Posts: n/a
Re: 86 CJ7 Failed Emissions Test -- Help
Hi Dan,
Do your normal tune up, Plugs, cap and ignition wires, maybe,
install a carburetor kit. Or install a new catalytic converter which
will burn the Hydrocarbons and change Carbon Monoxide into harmless
byproducts. My Bronco test: http://www.----------.com/smog.jpg It has
almost three hundred thousand miles on it, and the heads have never been
off.
God Bless America, ßill O|||||||O
mailto:-------------------- http://www.----------.com/
Dan Grulke wrote:
>
> My 86 CJ7 failed Virginia's strict emissions test, I need advice on
> how to get it to pass. I can do mechancial work myself if I know what
> to tackle. Here are the specifics:
> 15 MPH Test 25 MPH Test
> HC (Limit/Readings) 207/50 Pass 201/298 Fail
> CO 1.76/.01 Pass 2.29/4.69 Fail
> NO 3010/2192 Pass 2796/215 Pass
> RPM 1926 Valid 1279 Valid
> Dilution 14.9 Valid 16.8 Valid
>
> Visual components and smoke inspections passed.
> Thanks in advance for any hints you may be willing to offer. Dan
Do your normal tune up, Plugs, cap and ignition wires, maybe,
install a carburetor kit. Or install a new catalytic converter which
will burn the Hydrocarbons and change Carbon Monoxide into harmless
byproducts. My Bronco test: http://www.----------.com/smog.jpg It has
almost three hundred thousand miles on it, and the heads have never been
off.
God Bless America, ßill O|||||||O
mailto:-------------------- http://www.----------.com/
Dan Grulke wrote:
>
> My 86 CJ7 failed Virginia's strict emissions test, I need advice on
> how to get it to pass. I can do mechancial work myself if I know what
> to tackle. Here are the specifics:
> 15 MPH Test 25 MPH Test
> HC (Limit/Readings) 207/50 Pass 201/298 Fail
> CO 1.76/.01 Pass 2.29/4.69 Fail
> NO 3010/2192 Pass 2796/215 Pass
> RPM 1926 Valid 1279 Valid
> Dilution 14.9 Valid 16.8 Valid
>
> Visual components and smoke inspections passed.
> Thanks in advance for any hints you may be willing to offer. Dan
10-21-2003, 04:47 PM
#8
Guest
Posts: n/a
Re: 86 CJ7 Failed Emissions Test -- Help
c wrote:
>
> "Dan Grulke" <dwgrulke@mindspring.com> wrote in message
> news:9be7d463.0310211100.6158f3ab@posting.google.c om...
> > My 86 CJ7 failed Virginia's strict emissions test, I need advice on
> > how to get it to pass. I can do mechancial work myself if I know what
> > to tackle. Here are the specifics:
> > 15 MPH Test 25 MPH Test
> > HC (Limit/Readings) 207/50 Pass 201/298 Fail
> > CO 1.76/.01 Pass 2.29/4.69 Fail
> > NO 3010/2192 Pass 2796/215 Pass
> > RPM 1926 Valid 1279 Valid
> > Dilution 14.9 Valid 16.8 Valid
> >
> > Visual components and smoke inspections passed.
> > Thanks in advance for any hints you may be willing to offer. Dan
>
> Just found this on a website:
>
> CRUISE EMISSIONS
> At cruise, the engine is lightly loaded and running at high rpm. Under these
> conditions, HC and CO should be low if the oxygen sensor and feed back
> control system are working properly, and the catalytic converter is in good
> condition.
>
> High CO readings during cruise indicate a rich fuel condition. Causes here
> may include:
> . Defective O2 sensor;
> . Exhaust leaks upstream of the O2 sensor (check manifold gaskets and air
> plumbing connections);
> . Defective AIR pump or diverter valve (also loose or damaged air pump
> plumbing);
> . Defective MAP, MAF or VAF sensor;
> . Float level and operation (older carbureted engines); and
> . Power valve operation (older carbureted engines).
> High HC during cruise would indicate a steady misfire or loss of compression
> (leaky exhaust valve).
>
> This should give you some things to check for. Also, because it seems you
> are running rich, check the air filter and choke for proper operation. I
> would also check to make sure the EGR valve (if it has one) is functioning
> properly.
>
> Chris
EGR valve comes to mind, but those readings could just indicate the need
for a new air filter or a new cap and rotor.
When was the last time the plugs were changed?
Mike
86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
88 Cherokee 235 BFG AT's
>
> "Dan Grulke" <dwgrulke@mindspring.com> wrote in message
> news:9be7d463.0310211100.6158f3ab@posting.google.c om...
> > My 86 CJ7 failed Virginia's strict emissions test, I need advice on
> > how to get it to pass. I can do mechancial work myself if I know what
> > to tackle. Here are the specifics:
> > 15 MPH Test 25 MPH Test
> > HC (Limit/Readings) 207/50 Pass 201/298 Fail
> > CO 1.76/.01 Pass 2.29/4.69 Fail
> > NO 3010/2192 Pass 2796/215 Pass
> > RPM 1926 Valid 1279 Valid
> > Dilution 14.9 Valid 16.8 Valid
> >
> > Visual components and smoke inspections passed.
> > Thanks in advance for any hints you may be willing to offer. Dan
>
> Just found this on a website:
>
> CRUISE EMISSIONS
> At cruise, the engine is lightly loaded and running at high rpm. Under these
> conditions, HC and CO should be low if the oxygen sensor and feed back
> control system are working properly, and the catalytic converter is in good
> condition.
>
> High CO readings during cruise indicate a rich fuel condition. Causes here
> may include:
> . Defective O2 sensor;
> . Exhaust leaks upstream of the O2 sensor (check manifold gaskets and air
> plumbing connections);
> . Defective AIR pump or diverter valve (also loose or damaged air pump
> plumbing);
> . Defective MAP, MAF or VAF sensor;
> . Float level and operation (older carbureted engines); and
> . Power valve operation (older carbureted engines).
> High HC during cruise would indicate a steady misfire or loss of compression
> (leaky exhaust valve).
>
> This should give you some things to check for. Also, because it seems you
> are running rich, check the air filter and choke for proper operation. I
> would also check to make sure the EGR valve (if it has one) is functioning
> properly.
>
> Chris
EGR valve comes to mind, but those readings could just indicate the need
for a new air filter or a new cap and rotor.
When was the last time the plugs were changed?
Mike
86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
88 Cherokee 235 BFG AT's
10-21-2003, 04:47 PM
#9
Guest
Posts: n/a
Re: 86 CJ7 Failed Emissions Test -- Help
c wrote:
>
> "Dan Grulke" <dwgrulke@mindspring.com> wrote in message
> news:9be7d463.0310211100.6158f3ab@posting.google.c om...
> > My 86 CJ7 failed Virginia's strict emissions test, I need advice on
> > how to get it to pass. I can do mechancial work myself if I know what
> > to tackle. Here are the specifics:
> > 15 MPH Test 25 MPH Test
> > HC (Limit/Readings) 207/50 Pass 201/298 Fail
> > CO 1.76/.01 Pass 2.29/4.69 Fail
> > NO 3010/2192 Pass 2796/215 Pass
> > RPM 1926 Valid 1279 Valid
> > Dilution 14.9 Valid 16.8 Valid
> >
> > Visual components and smoke inspections passed.
> > Thanks in advance for any hints you may be willing to offer. Dan
>
> Just found this on a website:
>
> CRUISE EMISSIONS
> At cruise, the engine is lightly loaded and running at high rpm. Under these
> conditions, HC and CO should be low if the oxygen sensor and feed back
> control system are working properly, and the catalytic converter is in good
> condition.
>
> High CO readings during cruise indicate a rich fuel condition. Causes here
> may include:
> . Defective O2 sensor;
> . Exhaust leaks upstream of the O2 sensor (check manifold gaskets and air
> plumbing connections);
> . Defective AIR pump or diverter valve (also loose or damaged air pump
> plumbing);
> . Defective MAP, MAF or VAF sensor;
> . Float level and operation (older carbureted engines); and
> . Power valve operation (older carbureted engines).
> High HC during cruise would indicate a steady misfire or loss of compression
> (leaky exhaust valve).
>
> This should give you some things to check for. Also, because it seems you
> are running rich, check the air filter and choke for proper operation. I
> would also check to make sure the EGR valve (if it has one) is functioning
> properly.
>
> Chris
EGR valve comes to mind, but those readings could just indicate the need
for a new air filter or a new cap and rotor.
When was the last time the plugs were changed?
Mike
86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
88 Cherokee 235 BFG AT's
>
> "Dan Grulke" <dwgrulke@mindspring.com> wrote in message
> news:9be7d463.0310211100.6158f3ab@posting.google.c om...
> > My 86 CJ7 failed Virginia's strict emissions test, I need advice on
> > how to get it to pass. I can do mechancial work myself if I know what
> > to tackle. Here are the specifics:
> > 15 MPH Test 25 MPH Test
> > HC (Limit/Readings) 207/50 Pass 201/298 Fail
> > CO 1.76/.01 Pass 2.29/4.69 Fail
> > NO 3010/2192 Pass 2796/215 Pass
> > RPM 1926 Valid 1279 Valid
> > Dilution 14.9 Valid 16.8 Valid
> >
> > Visual components and smoke inspections passed.
> > Thanks in advance for any hints you may be willing to offer. Dan
>
> Just found this on a website:
>
> CRUISE EMISSIONS
> At cruise, the engine is lightly loaded and running at high rpm. Under these
> conditions, HC and CO should be low if the oxygen sensor and feed back
> control system are working properly, and the catalytic converter is in good
> condition.
>
> High CO readings during cruise indicate a rich fuel condition. Causes here
> may include:
> . Defective O2 sensor;
> . Exhaust leaks upstream of the O2 sensor (check manifold gaskets and air
> plumbing connections);
> . Defective AIR pump or diverter valve (also loose or damaged air pump
> plumbing);
> . Defective MAP, MAF or VAF sensor;
> . Float level and operation (older carbureted engines); and
> . Power valve operation (older carbureted engines).
> High HC during cruise would indicate a steady misfire or loss of compression
> (leaky exhaust valve).
>
> This should give you some things to check for. Also, because it seems you
> are running rich, check the air filter and choke for proper operation. I
> would also check to make sure the EGR valve (if it has one) is functioning
> properly.
>
> Chris
EGR valve comes to mind, but those readings could just indicate the need
for a new air filter or a new cap and rotor.
When was the last time the plugs were changed?
Mike
86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
88 Cherokee 235 BFG AT's
10-21-2003, 04:47 PM
#10
Guest
Posts: n/a
Re: 86 CJ7 Failed Emissions Test -- Help
c wrote:
>
> "Dan Grulke" <dwgrulke@mindspring.com> wrote in message
> news:9be7d463.0310211100.6158f3ab@posting.google.c om...
> > My 86 CJ7 failed Virginia's strict emissions test, I need advice on
> > how to get it to pass. I can do mechancial work myself if I know what
> > to tackle. Here are the specifics:
> > 15 MPH Test 25 MPH Test
> > HC (Limit/Readings) 207/50 Pass 201/298 Fail
> > CO 1.76/.01 Pass 2.29/4.69 Fail
> > NO 3010/2192 Pass 2796/215 Pass
> > RPM 1926 Valid 1279 Valid
> > Dilution 14.9 Valid 16.8 Valid
> >
> > Visual components and smoke inspections passed.
> > Thanks in advance for any hints you may be willing to offer. Dan
>
> Just found this on a website:
>
> CRUISE EMISSIONS
> At cruise, the engine is lightly loaded and running at high rpm. Under these
> conditions, HC and CO should be low if the oxygen sensor and feed back
> control system are working properly, and the catalytic converter is in good
> condition.
>
> High CO readings during cruise indicate a rich fuel condition. Causes here
> may include:
> . Defective O2 sensor;
> . Exhaust leaks upstream of the O2 sensor (check manifold gaskets and air
> plumbing connections);
> . Defective AIR pump or diverter valve (also loose or damaged air pump
> plumbing);
> . Defective MAP, MAF or VAF sensor;
> . Float level and operation (older carbureted engines); and
> . Power valve operation (older carbureted engines).
> High HC during cruise would indicate a steady misfire or loss of compression
> (leaky exhaust valve).
>
> This should give you some things to check for. Also, because it seems you
> are running rich, check the air filter and choke for proper operation. I
> would also check to make sure the EGR valve (if it has one) is functioning
> properly.
>
> Chris
EGR valve comes to mind, but those readings could just indicate the need
for a new air filter or a new cap and rotor.
When was the last time the plugs were changed?
Mike
86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
88 Cherokee 235 BFG AT's
>
> "Dan Grulke" <dwgrulke@mindspring.com> wrote in message
> news:9be7d463.0310211100.6158f3ab@posting.google.c om...
> > My 86 CJ7 failed Virginia's strict emissions test, I need advice on
> > how to get it to pass. I can do mechancial work myself if I know what
> > to tackle. Here are the specifics:
> > 15 MPH Test 25 MPH Test
> > HC (Limit/Readings) 207/50 Pass 201/298 Fail
> > CO 1.76/.01 Pass 2.29/4.69 Fail
> > NO 3010/2192 Pass 2796/215 Pass
> > RPM 1926 Valid 1279 Valid
> > Dilution 14.9 Valid 16.8 Valid
> >
> > Visual components and smoke inspections passed.
> > Thanks in advance for any hints you may be willing to offer. Dan
>
> Just found this on a website:
>
> CRUISE EMISSIONS
> At cruise, the engine is lightly loaded and running at high rpm. Under these
> conditions, HC and CO should be low if the oxygen sensor and feed back
> control system are working properly, and the catalytic converter is in good
> condition.
>
> High CO readings during cruise indicate a rich fuel condition. Causes here
> may include:
> . Defective O2 sensor;
> . Exhaust leaks upstream of the O2 sensor (check manifold gaskets and air
> plumbing connections);
> . Defective AIR pump or diverter valve (also loose or damaged air pump
> plumbing);
> . Defective MAP, MAF or VAF sensor;
> . Float level and operation (older carbureted engines); and
> . Power valve operation (older carbureted engines).
> High HC during cruise would indicate a steady misfire or loss of compression
> (leaky exhaust valve).
>
> This should give you some things to check for. Also, because it seems you
> are running rich, check the air filter and choke for proper operation. I
> would also check to make sure the EGR valve (if it has one) is functioning
> properly.
>
> Chris
EGR valve comes to mind, but those readings could just indicate the need
for a new air filter or a new cap and rotor.
When was the last time the plugs were changed?
Mike
86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
88 Cherokee 235 BFG AT's