"bllsht" <nospam@invaliddot.net> wrote in message
news:do7if2t80lckkssrrlopqojvvj7dvk3uos@4ax.com...
> In message <1157156154.271504.35920@m73g2000cwd.googlegroups. com>,
"Stevil"
> wrote:
>
> >Hello All,
> >
> >My 89 4.2L YJ just failed its smog on HC, results as follows...
> >
> >15mph MAX 124 AVG 34 MEASURE 125
> >25mph MAX 104 AVG 23 MEASURE 104
> >
> >As you can see it was a real close one, it was well below average on CO
> >and NO.
> >
> >I should have put two and two together as I noticed the other day some
> >soot build-up on the tail pipe. SO my question is beyond changing the
> >PCV valve, an oil change, and high octane gas, is there anything else I
> >can do? I changed the PCV valve, distributor cap, rotor and ignition
> >wires three months ago, do you think changing the sparks would help
> >any?
> >
> >Thank you in advance for your time and consideration of this matter and
> >your replies.
> >
> >Cheers, kind regards,
> >Steve
>
> Some soot on the tail pipe is pretty much normal on a vehicle with a cat
> converter. If there was a lot of it, that would indicate it's running
> rich, but if your CO readings were low, it's not rich. High octane gas
> might help a little with high NOx, but won't do a thing for HC.
>
> HC is unburned fuel. Anything that can cause a misfire could cause this.
> Ignition problems, or a lean mixture would be what I'd look for first.
> Make sure the timing is where it belongs. Could also be a dead cat
> or air injection system.
>
Along with the misfire idea, change the spark plugs. If the air injection
system is sub-standard, that would give you a point or two on the HC too.
On a vehicle this old, often the pump seizes up and someone puts plugs in
the holes for the AIR nozzles.

Earle

 

"bllsht" <nospam@invaliddot.net> wrote in message
news:do7if2t80lckkssrrlopqojvvj7dvk3uos@4ax.com...
> In message <1157156154.271504.35920@m73g2000cwd.googlegroups. com>,
"Stevil"
> wrote:
>
> >Hello All,
> >
> >My 89 4.2L YJ just failed its smog on HC, results as follows...
> >
> >15mph MAX 124 AVG 34 MEASURE 125
> >25mph MAX 104 AVG 23 MEASURE 104
> >
> >As you can see it was a real close one, it was well below average on CO
> >and NO.
> >
> >I should have put two and two together as I noticed the other day some
> >soot build-up on the tail pipe. SO my question is beyond changing the
> >PCV valve, an oil change, and high octane gas, is there anything else I
> >can do? I changed the PCV valve, distributor cap, rotor and ignition
> >wires three months ago, do you think changing the sparks would help
> >any?
> >
> >Thank you in advance for your time and consideration of this matter and
> >your replies.
> >
> >Cheers, kind regards,
> >Steve
>
> Some soot on the tail pipe is pretty much normal on a vehicle with a cat
> converter. If there was a lot of it, that would indicate it's running
> rich, but if your CO readings were low, it's not rich. High octane gas
> might help a little with high NOx, but won't do a thing for HC.
>
> HC is unburned fuel. Anything that can cause a misfire could cause this.
> Ignition problems, or a lean mixture would be what I'd look for first.
> Make sure the timing is where it belongs. Could also be a dead cat
> or air injection system.
>
Along with the misfire idea, change the spark plugs. If the air injection
system is sub-standard, that would give you a point or two on the HC too.
On a vehicle this old, often the pump seizes up and someone puts plugs in
the holes for the AIR nozzles.

Earle

 

"bllsht" <nospam@invaliddot.net> wrote in message
news:do7if2t80lckkssrrlopqojvvj7dvk3uos@4ax.com...
> In message <1157156154.271504.35920@m73g2000cwd.googlegroups. com>,
"Stevil"
> wrote:
>
> >Hello All,
> >
> >My 89 4.2L YJ just failed its smog on HC, results as follows...
> >
> >15mph MAX 124 AVG 34 MEASURE 125
> >25mph MAX 104 AVG 23 MEASURE 104
> >
> >As you can see it was a real close one, it was well below average on CO
> >and NO.
> >
> >I should have put two and two together as I noticed the other day some
> >soot build-up on the tail pipe. SO my question is beyond changing the
> >PCV valve, an oil change, and high octane gas, is there anything else I
> >can do? I changed the PCV valve, distributor cap, rotor and ignition
> >wires three months ago, do you think changing the sparks would help
> >any?
> >
> >Thank you in advance for your time and consideration of this matter and
> >your replies.
> >
> >Cheers, kind regards,
> >Steve
>
> Some soot on the tail pipe is pretty much normal on a vehicle with a cat
> converter. If there was a lot of it, that would indicate it's running
> rich, but if your CO readings were low, it's not rich. High octane gas
> might help a little with high NOx, but won't do a thing for HC.
>
> HC is unburned fuel. Anything that can cause a misfire could cause this.
> Ignition problems, or a lean mixture would be what I'd look for first.
> Make sure the timing is where it belongs. Could also be a dead cat
> or air injection system.
>
Along with the misfire idea, change the spark plugs. If the air injection
system is sub-standard, that would give you a point or two on the HC too.
On a vehicle this old, often the pump seizes up and someone puts plugs in
the holes for the AIR nozzles.

Earle

 

A clean air filter does wonders for HC emissions, so does new plugs....

I would also recommend you check the new distributor cap and rotor out.
There are a bad batch of them out on store shelves. The rotors are too
short and start arcing out very soon after installing them.

High octane might help smooth things out if it sputters at idle. Your
engine calls for high test if running hot and loaded to avoid engine
ping.

Mike
86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
88 Cherokee 235 BFG AT's
Canadian Off Road Trips Photos: Non members can still view!
Jan/06 http://www.imagestation.com/album/pi...?id=2115147590
(More Off Road album links at bottom of the view page)

Stevil wrote:
>
> Hello All,
>
> My 89 4.2L YJ just failed its smog on HC, results as follows...
>
> 15mph MAX 124 AVG 34 MEASURE 125
> 25mph MAX 104 AVG 23 MEASURE 104
>
> As you can see it was a real close one, it was well below average on CO
> and NO.
>
> I should have put two and two together as I noticed the other day some
> soot build-up on the tail pipe. SO my question is beyond changing the
> PCV valve, an oil change, and high octane gas, is there anything else I
> can do? I changed the PCV valve, distributor cap, rotor and ignition
> wires three months ago, do you think changing the sparks would help
> any?
>
> Thank you in advance for your time and consideration of this matter and
> your replies.
>
> Cheers, kind regards,
> Steve

 

A clean air filter does wonders for HC emissions, so does new plugs....

I would also recommend you check the new distributor cap and rotor out.
There are a bad batch of them out on store shelves. The rotors are too
short and start arcing out very soon after installing them.

High octane might help smooth things out if it sputters at idle. Your
engine calls for high test if running hot and loaded to avoid engine
ping.

Mike
86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
88 Cherokee 235 BFG AT's
Canadian Off Road Trips Photos: Non members can still view!
Jan/06 http://www.imagestation.com/album/pi...?id=2115147590
(More Off Road album links at bottom of the view page)

Stevil wrote:
>
> Hello All,
>
> My 89 4.2L YJ just failed its smog on HC, results as follows...
>
> 15mph MAX 124 AVG 34 MEASURE 125
> 25mph MAX 104 AVG 23 MEASURE 104
>
> As you can see it was a real close one, it was well below average on CO
> and NO.
>
> I should have put two and two together as I noticed the other day some
> soot build-up on the tail pipe. SO my question is beyond changing the
> PCV valve, an oil change, and high octane gas, is there anything else I
> can do? I changed the PCV valve, distributor cap, rotor and ignition
> wires three months ago, do you think changing the sparks would help
> any?
>
> Thank you in advance for your time and consideration of this matter and
> your replies.
>
> Cheers, kind regards,
> Steve

 

A clean air filter does wonders for HC emissions, so does new plugs....

I would also recommend you check the new distributor cap and rotor out.
There are a bad batch of them out on store shelves. The rotors are too
short and start arcing out very soon after installing them.

High octane might help smooth things out if it sputters at idle. Your
engine calls for high test if running hot and loaded to avoid engine
ping.

Mike
86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
88 Cherokee 235 BFG AT's
Canadian Off Road Trips Photos: Non members can still view!
Jan/06 http://www.imagestation.com/album/pi...?id=2115147590
(More Off Road album links at bottom of the view page)

Stevil wrote:
>
> Hello All,
>
> My 89 4.2L YJ just failed its smog on HC, results as follows...
>
> 15mph MAX 124 AVG 34 MEASURE 125
> 25mph MAX 104 AVG 23 MEASURE 104
>
> As you can see it was a real close one, it was well below average on CO
> and NO.
>
> I should have put two and two together as I noticed the other day some
> soot build-up on the tail pipe. SO my question is beyond changing the
> PCV valve, an oil change, and high octane gas, is there anything else I
> can do? I changed the PCV valve, distributor cap, rotor and ignition
> wires three months ago, do you think changing the sparks would help
> any?
>
> Thank you in advance for your time and consideration of this matter and
> your replies.
>
> Cheers, kind regards,
> Steve