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Hi HC's in '93 Chev. Astro van



 
 
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  #1  
Old January 25th 05, 02:14 AM
Rayvan
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Default Hi HC's in '93 Chev. Astro van

My Van (1993 Astro engine code W 154,000 miles)
is failing California's smog requirement.

Tested the van on rollers under load and found this:

HC's at 15 MPH (1475 RPM):
164 PPM. Allowed: 88 PPM max.

It passes in CO% and it passes for NOx (PPM) with flying colors
and in the 25 MPH test it passes all three w/no problems...
It runs clean at idle, and it runs clean at 2500 RPM (no load)

The van has never failed smog before and otherwise runs perfectly. This
is the first time it's ever had to run on the rollers under load.

In an attempt to fix it I just replaced all the fuel injectors and the
fuel pressure regulator, pcv valve. It now runs a bit cleaner:

It now fails w/109 PPM HC (down from 164. It's allowed 88)

The van has had a fairly recent tune-up that included ign. wires,
plugs, rotor, fuel filter, cleaned the K&N filter etc. This was only
about 10,000 miles ago.

Compression is good, starts right up, no CES codes, runs with about the
same fuel economy as it ever has...

So basically it only belches out smog when I cruise around in a parking
lot. What the heck do I do now?

Thanks,

Rayvan

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  #2  
Old January 25th 05, 08:19 AM
Ted Mittelstaedt
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Default


"Rayvan" > wrote in message
ups.com...
> My Van (1993 Astro engine code W 154,000 miles)
> is failing California's smog requirement.
>
> Tested the van on rollers under load and found this:
>
> HC's at 15 MPH (1475 RPM):
> 164 PPM. Allowed: 88 PPM max.
>
> It passes in CO% and it passes for NOx (PPM) with flying colors
> and in the 25 MPH test it passes all three w/no problems...
> It runs clean at idle, and it runs clean at 2500 RPM (no load)
>
> The van has never failed smog before and otherwise runs perfectly. This
> is the first time it's ever had to run on the rollers under load.
>
> In an attempt to fix it I just replaced all the fuel injectors and the
> fuel pressure regulator, pcv valve. It now runs a bit cleaner:
>
> It now fails w/109 PPM HC (down from 164. It's allowed 88)
>
> The van has had a fairly recent tune-up that included ign. wires,
> plugs, rotor, fuel filter, cleaned the K&N filter etc. This was only
> about 10,000 miles ago.
>
> Compression is good, starts right up, no CES codes, runs with about the
> same fuel economy as it ever has...
>
> So basically it only belches out smog when I cruise around in a parking
> lot. What the heck do I do now?
>


If the PVC valve wasn't working the oil might be contaminated with
blowby, change the oil.

Your catcon is probably carboned up from whatever was making it run too
rich (possibly something in the fuel, although you were obviously
shotgunning
when you replaced the injectors and regulator and just got lucky that
whatever
you did affected it) and as a result is falling off in efficiency. Since
your so close to passing,
after you change the oil, take it out on the highway and drive at high speed
(65-70) for an hour or two. If you can arrainge to drive straight from that
into a
testing station and get it tested immediately, while the cat is still quite
hot,
it might pass. If you throw in a bottle of gas tank drier, (which is
basically
alcohol) before the test that might give a few extra ppm, although the
computer will undoubtedly compensate for this.

You also might try a few tankfuls of gasoline from a different gas station.

These are really irritating ones because since they are so close to passing
the
economic temptation is very high to just rubber-band the thing to get it to
pass.
Too bad you spent all that money on injectors and a regulator instead of
whatever is really busted (probably the catcon), which is the too often sad
story of someone trying to diagnose
it with a voodoo doll instead of a proper shop manual.

Almost certainly though if you get it passed this time, next time your
definitely
going to have to spend come coin on it.

Ted


  #3  
Old January 26th 05, 12:02 AM
Rayvan
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Posts: n/a
Default

Naw I wasn't shotgunning. The van was dying when cold for the past few
months and the fuel pressure was dropping far too fast.
The Reg and the injectors are all one piece on this setup. Runs much
better, but still needs a cat con. A temp test revealed that the front
of the unit was hotter than the rear when the opposite should be true.
The converter is not convertin'

Thanks for the reply.

Rayvan

 




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