91 Wrangler failed emissions

Earle Horton wrote:

> The CO is high because the engine is running poorly.

If the ignition system were malfunctioning, his HC would be high, and the cats
would likely be toast from overheating.

High CO/NOx levels are always due to unusually high combustion chamber temps;
NIH (not invented here) is taken care of downstream at the cats. There are a
variety of reasons this will come up high, but some careful sleuthing will
find it.

A good article on this can be found at:

http://findarticles.com/p/articles/m...06/ai_n8857473

I'm pretty good friends with an ASE-type who owns his own smog-check shop.
Most of the time, this is simply a plugged or non-op EGR valve. Second most
common problem are guys who noodle with their timing, overadvancing it too far.

You may need a new catalytic converter:
http://auto.howstuffworks.com/catalytic-converter2.htm You may see how one
works on my a car with 350,000 miles: http://billhughes.com/temp/smog07.jpg
God Bless America, Bill O|||||||O

http://www.billhughes.com/jeep_bookmark.htm

> wrote in message
...
>
> I've posted the numbers to
http://picasaweb.google.com/testert555/Emissions
>
> Any incite would be appreciated.
>
>
> CTM




--
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Mike Romain wrote:
> wrote:
>> On Feb 28, 8:18 pm, Outatime > wrote:
>>> wrote:
>>>> My 91 Wrangler 4.0 failed emissions.
>>>> Any tips for getting it to pass? Should I run a full tank of gas
>>>> through it before having it retested?
>>> Sorry to hear that you've failed your emissions inspection. Before
>>> you fix
>>> anything, it is important to know why you failed.
>>>
>>> Can you provide some numbers? Was your HC count high? At idle? At
>>> speed?
>>> Can you provide the numbers or even better, a photograph/scan of the
>>> actual
>>> readout? This would help tremendously.
>>>
>>> Changing oil, cleaning fuel injectors, filling up, praying,
>>> installing fuel
>>> line magnets, sacrificing a virgin at an alter at Midnight during a
>>> Full Moon,
>>> etc. won't help.
>>>
>>> Get a 3-mo. registration extension from DMV, then get more
>>> information before
>>> proceeding. It's probably something very easily repaired, so don't
>>> panic.
>>> And don't let the testing facility do any repairs. If they were
>>> competent,
>>> they would already know what the problem is.
>>
>> I've posted the numbers to
>> http://picasaweb.google.com/testert555/Emissions
>>
>> Any incite would be appreciated.
>>
>>
>> CTM
>
> I would get a 'good' penetrating oil, something like PB Blaster or even
> Liquid Wrench and soak the crap out of those distributor screws. They
> 'do' snap really easily and drilling them out for a nut and bolt is sure
> a pain.
>
> The distributor affects the timing and spark and the only 'fix' you have
> there is the cap and rotor, the timing isn't adjustable on that engine.
>
> If you still are running the original O2, it can't hurt to change it.
>
> The induction clean helps for high HC's which is why I was asking about
> oil spits into the air filter. the induction cleaning 'did' help our 88
> 4.0, but it was totally soaked in oil after the usual failure of the CCV
> system. (blocked rear line)
>
> A good run at high rpm, like keeping it in 3rd and 4th with some 'hard'
> acceleration on the on ramps on the highway or a good high rpm off road
> run in 4 low will help to blow any buildup in the combustion chamber
> which might be contributing to the high NOx. Does it ping under load or
> run on after you turn off the key? If so, another 'fix' might be in
> order, a carbon clean.
>
> And after that, if it still fails, I would go for a Cat I guess.

I just looked it up, you 'do' have an EGR, I didn't think you did. I
would remove that and clean it. A really good soak in carb cleaner does
that valve wonders.

>
> Mike
> 86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
> 'New' frame in the works for '08. Some Canadian Bush Trip and Build
> Photos: http://mikeromainjeeptrips.shutterfly.com

Original post says "It's been getting bad mileage for a while." Like I
said, it is an error to do anything until you assure yourself that the
ignition system is up to par. Age and frozen distributor cap screws says
this stuff needs replaced. I'll bet the plug wires are original. "Careful
sleuthing" is a cute phrase, but it is no substitute for conscientious
maintenance.

Saludos,

Earle

"Outatime" > wrote in message
news
> Earle Horton wrote:
>
>> The CO is high because the engine is running poorly.
>
> If the ignition system were malfunctioning, his HC would be high, and the
> cats would likely be toast from overheating.
>
> High CO/NOx levels are always due to unusually high combustion chamber
> temps; NIH (not invented here) is taken care of downstream at the cats.
> There are a variety of reasons this will come up high, but some careful
> sleuthing will find it.
>
> A good article on this can be found at:
>
> http://findarticles.com/p/articles/m...06/ai_n8857473
>
> I'm pretty good friends with an ASE-type who owns his own smog-check shop.
> Most of the time, this is simply a plugged or non-op EGR valve. Second
> most common problem are guys who noodle with their timing, overadvancing
> it too far.
>
>
>

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Posted via a free Usenet account from http://www.teranews.com

Mike Romain wrote:

> I just looked it up, you 'do' have an EGR, I didn't think you did. I
> would remove that and clean it. A really good soak in carb cleaner does
> that valve wonders.

Bingo! I agree with Mike: remove the EGR and clean that sucker with carb
cleaner and a stiff brush, and be sure that the passageways are clean as well.
Install a new gasket upon reassembly. If the hose(s) that connect to it
are worn out, replace them.

Around here, techs check EGR operation before even beginning the exhaust
testing because EGR valve failures are so common.

Believe it or not, the #1 reason that EGR valves do not function properly:
aftermarket junk! Yes, it's true. People often replace their EGR valve with
aftermarket parts that flat-out don't work, right out of the box. Those
in-the-know *always* replace EGR valves with OEM parts, regardless of cost.

I'm guilty as anyone on this. I once replaced an old, worn-out EGR valve on
an old Chevy-Beater with $60 aftermarket junk. 6-months later, I failed a
smog check, and to my surprise, the EGR valve came up non-op. The tech
explained to me that most aftermarket EGR's are junk, and that replacing it
with an OEM valve would take care of the problem. $46.00 and one OEM EGR
valve later, it passed with flying colors.

Imagine that. Expensive, aftermarket junk that cost me more money that it was
worth in retest charges. Want to know how much money aftermarket parts
suppliers get from me these days? NADA. To hell with 'em.

"Outatime" > wrote in message
...
> Mike Romain wrote:
>
>> I just looked it up, you 'do' have an EGR, I didn't think you did. I
>> would remove that and clean it. A really good soak in carb cleaner does
>> that valve wonders.
>
> Bingo! I agree with Mike: remove the EGR and clean that sucker with carb
> cleaner and a stiff brush, and be sure that the passageways are clean as
> well. Install a new gasket upon reassembly. If the hose(s) that connect
> to it are worn out, replace them.
>
> Around here, techs check EGR operation before even beginning the exhaust
> testing because EGR valve failures are so common.
>
> Believe it or not, the #1 reason that EGR valves do not function properly:
> aftermarket junk! Yes, it's true. People often replace their EGR valve
> with

Funny that this sort of part is "always" out-sourced, and the OEM and
aftermarket parts are usually identical. A bad EGR could raise combustion
temperatures, especially at the 25 mph setting, but that is not going to
explain the OP's bad gas mileage complaint. Fixing the emissions while the
car continues to run like crap and burn too much gas is like ****ing into
the wind.

Cheers,

Earle


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Earle Horton wrote:

> Funny that this sort of part is "always" out-sourced, and the OEM and
> aftermarket parts are usually identical.

The Earth is round.

On Sat, 01 Mar 2008 10:57:06 -0800, Outatime
> wrote:

>Earle Horton wrote:
>
>> Funny that this sort of part is "always" out-sourced, and the OEM and
>> aftermarket parts are usually identical.
>
>The Earth is round.

A 1991 4.0L Wrangler doesn't have EGR.
A 1991 4.0L Wrangler doesn't have adjustable timing.
High CO is caused by a rich mixture, NOT high combustion temps.

"bllsht" > wrote in message
...
> On Sat, 01 Mar 2008 10:57:06 -0800, Outatime
> > wrote:
>
>>Earle Horton wrote:
>>
>>> Funny that this sort of part is "always" out-sourced, and the
>>> OEM and aftermarket parts are usually identical.
>>
>>The Earth is round.
>
> A 1991 4.0L Wrangler doesn't have EGR.
> A 1991 4.0L Wrangler doesn't have adjustable timing.
> High CO is caused by a rich mixture, NOT high combustion temps.
>
Look this guy claims to know someone who is ASE certified. I can't top
that. I wouldn't know anyone who was ASE certified. I just have a degree
in Physics, how lame is that?

We figured in 1978 when I was working in the Dodge garage that emissions
controls like EGR were just a scam to make the tree huggers think something
was being done. It turns out we were right. EGR lowers combustion temps
and inhibits formation of NO, but the cat does all the work in getting rid
of it. CO is a combustible gas, ergo high temperatures make it burn, duh.
The PCV valve was a good idea, computer controlled fuel injection was
another one.

Almost forty years experience tinkering with cars says that a properly tuned
engine burns cleaner and uses less fuel. Trying to get emissions controls
to work on an improperly tuned engine is like ****ing into the wind. I have
consistently gotten well-tuned vehicles to pass emissions certification,
with the EGR and various other Rube Goldberg devices removed. It's not
hard. If your state does a visual, then disable the offending device in one
way or another, but leave it in place. That's not hard either.

"Even a fool, when he holdeth his peace, is counted wise: and he that
shutteth his lips is esteemed a man of understanding."
Proverbs, 17:28.

"When a fool helps, the more he helps, the worse things get."
Chinese proverb.

"The fool learns by suffering."
Hesiod, Works and Days, 216.

"Doctores indoctos, nunca hubo pocos."
F. Caudet, Mejores refranes españoles, #2545


Cheers,

Earle


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On Sat, 1 Mar 2008 16:04:30 -0700, "Earle Horton"
> wrote:

>"bllsht" > wrote in message
.. .
>> On Sat, 01 Mar 2008 10:57:06 -0800, Outatime
>> > wrote:
>>
>>>Earle Horton wrote:
>>>
>>>> Funny that this sort of part is "always" out-sourced, and the
>>>> OEM and aftermarket parts are usually identical.
>>>
>>>The Earth is round.
>>
>> A 1991 4.0L Wrangler doesn't have EGR.
>> A 1991 4.0L Wrangler doesn't have adjustable timing.
>> High CO is caused by a rich mixture, NOT high combustion temps.
>>
>Look this guy claims to know someone who is ASE certified. I can't top
>that. I wouldn't know anyone who was ASE certified. I just have a degree
>in Physics, how lame is that?

"ASE certified" only means he passed a multiple guess test. I've known
"ASE certifed techs" that I wouldn't allow to put a spark plug in my
lawn mower, let alone diagnose a bad plug to begin with.

>
>We figured in 1978 when I was working in the Dodge garage that emissions
>controls like EGR were just a scam to make the tree huggers think something
>was being done. It turns out we were right. EGR lowers combustion temps
>and inhibits formation of NO, but the cat does all the work in getting rid
>of it. CO is a combustible gas, ergo high temperatures make it burn, duh.
>The PCV valve was a good idea, computer controlled fuel injection was
>another one.

EGR came along before the cat converter did, and it works. Until they
started using three way cats, the cat didn't to anything to reduce NOx
emissions.

Early EGR systems left a lot to be desired, but controls are a lot
better today. In fact, some vehicles are equipped with EGR because
they actually get slightly better fuel mileage, not because they
needed it to pass emission standards.

>
>Almost forty years experience tinkering with cars says that a properly tuned
>engine burns cleaner and uses less fuel. Trying to get emissions controls
>to work on an improperly tuned engine is like ****ing into the wind. I have
>consistently gotten well-tuned vehicles to pass emissions certification,
>with the EGR and various other Rube Goldberg devices removed. It's not
>hard. If your state does a visual, then disable the offending device in one
>way or another, but leave it in place. That's not hard either.

I agree with the properly tuned part. Emission controls are designed
to work on a properly tuned engine. However, in California, if you're
not doing an ASM (loaded mode) test, a functional test of the EGR
system is required. Sometimes just "being there" isn't enough.

>
>"Even a fool, when he holdeth his peace, is counted wise: and he that
>shutteth his lips is esteemed a man of understanding."
>Proverbs, 17:28.
>
>"When a fool helps, the more he helps, the worse things get."
>Chinese proverb.
>
>"The fool learns by suffering."
>Hesiod, Works and Days, 216.
>
>"Doctores indoctos, nunca hubo pocos."
>F. Caudet, Mejores refranes españoles, #2545
>
>
>Cheers,
>
>Earle