Thanks Don,
Good thing I looked in the bulk mail and found your email.
I go to the same smog shop, they know me and the truck as it failed
before the Cat was replaced then got down to 1ppm of HC when I replaced
the Cat! But that was three years ago and ~ 15k mi. It's in CA where
we have weird smog test and laws or at lease different from other 49
states.
Do you know about "Test-Only" smog test?
The truck was driven for about 45 mins all over town but not at
freeways speeds (which I wished I did). I went to a 'Gold Shield' Smog
shop. I got a misquote on the price over the phone and the owner was
acting outlandish so I took my biz elsewhare - back to the shop where I
had taken it before and there was no wait and the tech did run the
engine for a long time to get the temp up. He left it running on the
dyno when we went outside to see the police chase down ths guy who ran
into a house instead of the alley next to it, kiled three people in the
house. hint - don't buy a house next to an alley.
According to my Haynes and Chilton's shop manual it has a air pump and
air switch valve for V-8s of this year. And if it doesn't, how does
it get injected air into the CAT to catylize the unburnt fuel?
I just looked and Your are right, there isn't any Air Pump. So How
does it get Air Injection into the Cat?
The smog tech seems to think that because magnaflow makes a smaller Cat
it wears out quicker, well maybe but in 15k miles? Still got to do a
Temp diff. test and manifold Vac test to see if exhaust is clogged.
With gas prices going higher I'm using 87 octane gas instead of
midgrade or 89/91 octane. It might be adding to the HC as well.
I do know that there are more lousy shops for smog test or repair than
good ones. I think that's why they started the Gold Shield program in
CA. It's also the reason I work on the truck myself. Can't tell you
how many times I took it to a mechanic or the dealer and got sloppy
work.
Ron in Kali
--- Don Rey <radon220@gmail.com> wrote:
> Are you sure you have an air pump in your 94? I thought they got rid
> of those stupid smog pumps with the magnum engines.
>
> How close do you live to your testing station? How long did the truck
> sit, not running, before it was started and run on the dyno? For my
> last emissions test (before my engine swap... and coincidentally
> while
> I still had a smog pump) I took the truck to a chain muffler shop
> twice, failing both times, just over the limit on hydrocarbons. I
> replaced things like the O2 sensor and the air pump switch with no
> significant improvement. So I tried a different place... a smaller
> shop with much friendlier service. Here's the difference between the
> two shops:
>
> chain shop
> I drove 5 minutes from work to local chain shop, shut it off. It sat
> 10 minutes before they drove it onto the dyno and shut it off.
> Strapped it up, set up sniffers, twidled thumbs, booted computer...
> 20
> minutes later, started truck. Ran tests quickly, returned truck to
> lot
> with failing marks.
>
> small shop
> I drove 20 minutes to smaller shop, shut it off. It sat 10 minutes
> before they drove it onto the dyno and shut it off. Strapped it up,
> set up sniffers, started truck. *WHILE THE TRUCK RAN* they booted the
> computer, and tended other customers and tasks for 10-20 minutes. Ran
> tests noticeably longer than the chain shop, and returned it to the
> lot with passing marks.
>
> The key is testing the truck WARM. Any shop *should* know how
> important that is and should make sure the truck is warm first.
>
> Don in CT
> 89 DakVert with 94 5.2/5spd/4x4 which has not yet been emissions
> tested...
> 74 Dart Sport 340 emissions exempt :-D
>
>
> On 9/27/07, rws <rwsam2002@yahoo.com> wrote:
> >
> > Hi,
> >
> > I took the '94 Dak 4x4AT 5.2L @ 162k mi. in for the CA Smog Test
> and it
> > failed the 25mph test HC Passing is 50 and the Dak got 51, so it
> failed
> > by one.
> >
> > Cat converter (Magnaflow P/N 94006) was replaced Aug 2004.
> >
> > O2 sensor, ECT coolant sensor recent replaced, Ign. Coil, TPS
> replaced
> > 2 years ago.
> >
> > Magnaflow tech said to test Cat by Temp differential front and back
> of
> > the Cat and it should be 50-100oF difference. Temp will be around
> > 400-600oF, so I need to find a temp gage for that range and need to
> > find.
> >
> > But in the meantime I am suspecting the Air Pump or the Air Switch
> > Valve.
> >
> > How do I test Air Pump and Air Switch Valve components to make
> sure
> > air injection system is operating correctly? What is vacuum
> > measurement at the Air Switch Valve?
> >
> > Also I am wondering if it is not getting proper air injection will
> that
> > alter the temperature difference test on the CAT?
> >
> > ref:
> > 15 mph test HC 85 MAX 18AVG 85MEAS NOx 491MAX 149AVG 432MEAS %O2
> 0.1
> > 25 mph test HC 50 MAX 12AVG 51MEAS NOx 744MAX 144AVG 296MEAS %O2
> 0.2
> >
> > Please need help soon.
> >
> > Ron
> >
> >
> >
> >
>
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> > to amazing places on Yahoo! Travel.
> > http://travel.yahoo.com/
> >
> >
>
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