91 Wrangler failed emissions

All,

My 91 Wrangler 4.0 failed emissions. It has 136k miles. It's been
getting bad mileage for a while. I had the garage run their
diagnostics. Their recommendation was to change the O2 sensor, change
oil, do fuel induction service. I can change the O2 sensor and oil,
but what is the induction service? Adding something to the oil/gas or
both?

Any tips for getting it to pass? Should I run a full tank of gas
through it before having it retested?

Thank you,

CTM

wrote:
> All,
>
> My 91 Wrangler 4.0 failed emissions. It has 136k miles. It's been
> getting bad mileage for a while. I had the garage run their
> diagnostics. Their recommendation was to change the O2 sensor, change
> oil, do fuel induction service. I can change the O2 sensor and oil,
> but what is the induction service? Adding something to the oil/gas or
> both?
>
> Any tips for getting it to pass? Should I run a full tank of gas
> through it before having it retested?
>
> Thank you,
>
> CTM

When was the last time it got a new distributor cap and rotor or wires?

Cleaning the air intake (fuel induction system) sounds like you have an
oil blowing into the air filter issue? If so, there are fixes for that.

Fresh oil and air filter is always a good thing too.

Your O2 is likely due for a change. Does that 91 have the Renix
computer or the Chrysler one? If Renix, the O2 is a recall part.

What were your readings? High HC's?

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

On Feb 28, 3:46 pm, Mike Romain > wrote:
> wrote:
> > All,
>
> > My 91 Wrangler 4.0 failed emissions. It has 136k miles. It's been
> > getting bad mileage for a while. I had the garage run their
> > diagnostics. Their recommendation was to change the O2 sensor, change
> > oil, do fuel induction service. I can change the O2 sensor and oil,
> > but what is the induction service? Adding something to the oil/gas or
> > both?
>
> > Any tips for getting it to pass? Should I run a full tank of gas
> > through it before having it retested?
>
> > Thank you,
>
> > CTM
>
> When was the last time it got a new distributor cap and rotor or wires?
>
> Cleaning the air intake (fuel induction system) sounds like you have an
> oil blowing into the air filter issue? If so, there are fixes for that.
>
> Fresh oil and air filter is always a good thing too.
>
> Your O2 is likely due for a change. Does that 91 have the Renix
> computer or the Chrysler one? If Renix, the O2 is a recall part.
>
> What were your readings? High HC's?
>
> 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

Mike,
It's been a while since I've changed the cap and rotor. I tried doing
it last month and could not loosen the screws on the cap. I was
afraid of stripping or breaking them. So I changed the wires and plugs
only.

I've read other posts about oil in the air filter, and have never seen
any.

I have not picked up the readings yet. Will any of the readings point
to the catalytic converter as the issue? It is original.

Regarding the induction service. The shop sent me a link to
bgfindashop.com. I've heard lots of good things about bg products,
but was curious if this was necessary.

Thank you,
CTM

wrote:
> On Feb 28, 3:46 pm, Mike Romain > wrote:
>> wrote:
>>> All,
>>> My 91 Wrangler 4.0 failed emissions. It has 136k miles. It's been
>>> getting bad mileage for a while. I had the garage run their
>>> diagnostics. Their recommendation was to change the O2 sensor, change
>>> oil, do fuel induction service. I can change the O2 sensor and oil,
>>> but what is the induction service? Adding something to the oil/gas or
>>> both?
>>> Any tips for getting it to pass? Should I run a full tank of gas
>>> through it before having it retested?
>>> Thank you,
>>> CTM
>> When was the last time it got a new distributor cap and rotor or wires?
>>
>> Cleaning the air intake (fuel induction system) sounds like you have an
>> oil blowing into the air filter issue? If so, there are fixes for that.
>>
>> Fresh oil and air filter is always a good thing too.
>>
>> Your O2 is likely due for a change. Does that 91 have the Renix
>> computer or the Chrysler one? If Renix, the O2 is a recall part.
>>
>> What were your readings? High HC's?
>>
>> 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
>
> Mike,
> It's been a while since I've changed the cap and rotor. I tried doing
> it last month and could not loosen the screws on the cap. I was
> afraid of stripping or breaking them. So I changed the wires and plugs
> only.
>
> I've read other posts about oil in the air filter, and have never seen
> any.
>
> I have not picked up the readings yet. Will any of the readings point
> to the catalytic converter as the issue? It is original.
>
> Regarding the induction service. The shop sent me a link to
> bgfindashop.com. I've heard lots of good things about bg products,
> but was curious if this was necessary.
>
> Thank you,
> CTM
>
You need the readings.

Mike

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.

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

wrote:

> I've posted the numbers to http://picasaweb.google.com/testert555/Emissions

Interesting. High CO and NOx readings and okay HC's. Assuming that you don't
have severe overheating or pre-ignition problems, this should be easy to track
down.

Before retesting, have a mechanic check the following, in order of likeliness:

EGR valve malfunction (if applicable)
Incorrect ignition timing (overadvanced)
Worn catalytic converters
Excessive combustion chamber deposits
Worn timing chain (incorrect valve timing)

If you live in CA, the state will give you $300 toward repairs, but you must
have it done at an authorized facility and you must get pre-approval before
work is done; forms are available at the shop.

> wrote in message
...
> 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.
>
You don't want "incite" for this, heh. You want "insight". You will get
plenty of both in this group. Replace rotor, cap, and plug wires. Clean or
replace the PCV or CCV system, whichever it has. "Induction service" is a
nice touch, but it won't help your numbers. A clean air filter will do
that. It is important to get the vehicle running as well as possible,
before the test. Guys in Fort Collins let my Land Cruiser warm up real
good, after it failed on a cold engine. With your CO numbers like that, you
problem is basically nothing more, than that your engine runs like crap now.


Earle

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.

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

The CO is high because the engine is running poorly. An ignition tune-up
should fix that. I think (hope) that the NO readings will come into line
once the engine is running properly. The cat won't function properly unless
it is at the correct operating temperature. The NO is marginal and can
hopefully be fixed by properly tuning the engine, without a new cat. It is
an error with gasoline powered vehicles to look for performance problems
anywhere else, unless you are 100% confident in your ignition system
components.

Earle

"Outatime" > wrote in message
...
> wrote:
>
>> I've posted the numbers to
>> http://picasaweb.google.com/testert555/Emissions
>
> Interest
ing. High CO and NOx readings and okay HC's. Assuming that you don't
> have severe overheating or pre-ignition problems, this should be easy to
> track down.
>
> Before retesting, have a mechanic check the following, in order of
> likeliness:
>
> EGR valve malfunction (if applicable)
> Incorrect ignition timing (overadvanced)
> Worn catalytic converters
> Excessive combustion chamber deposits
> Worn timing chain (incorrect valve timing)
>
> If you live in CA, the state will give you $300 toward repairs, but you
> must have it done at an authorized facility and you must get pre-approval
> before work is done; forms are available at the shop.