Engine - Smog Test Tips

------------------------------

Date: Thu, 19 Mar 1998 20:18:23 -0800
From: Jim Brink 
Subject: Re: Downey Catalytic converter? Failed test! Anybody else have this
            problem.

Specilizd wrote:

> I have an 81 toy 4x4.   I just replaced the cat. with one sold by Downey
> off road. I did this because I wanted a bolt in job.  The brand name on 
> it is "Carsound"
> Well  it failed the california smog test.  The test tech was suspicious of
> the cat.
>
> Has anyone else used this CAT. and passed the test?
> 
> JIm Wrote::
>  According to CARB tests, the CarSound CATs are some of the best as far
>  as aftermarket CATs are concerned. My experience has shown them to be
>  better than other, non OEM brands as well.
> 
>  What was the reason your truck failed? Excessive HC or CO? Was it
>  possibly a dilution problem?
>  
> 
> OK here are the test results:
> 2500 RPM
>    Max Allowable                   Tested as.
> HC      200                        18
> CO        2.00                       .59
> CO2                                15.1
> O2                                  0.0
> 
> IDLE SPEED TESTS
>    Max Allowable                    Tested as.
> HC      250                         1001
> CO        2.00                         3.26
> CO2                                   12.6
> O2                                     0.9
> 
> I had the test done the day after I installed the new cat.   
> Put new plugs in.
> New air filter.
> Did some cleaning on the carb and linkage because it was sticking at high 
> idle before.  It drops down fine now.
> 
> It does seem awfully high for just being a cat.  I'm inclined to agree there
> is somthing else wrong here.

I would say that there is a carburetion problem here. 

Have you tried adjusting the idle mixture any? I would start at about 2
1/2 turns out from bottomed-out.

Is the choke plate opening fully? How about the internal cleanliness of
the carb? I wouldn't doubt, looking at these numbers, that the idle
circuits and air bleeds, plus the bowl vents are restricted. Try some
carb. cleaner and compressed air and give the carb. a good cleaning.

With CO numbers like that, there is no way even a new CAT could clean up
this motor. Focus your attention towards the carb. then check secondary
items like ignition timing including advance.

Jim Brink

------------------------------

Date: Sat, 04 Apr 1998 14:05:49 -0800
From: Jim Brink 
Subject: Re: 20R Header on 22R -Reply

Rob Ditusa wrote:
> This brings up something I encountered when I installed the Downey
> header on my 20R. It has the "flange" for the O2 sensor, which I blocked
> off, but my cat had a "probe" about six inches long sticking into it (I 
> also installed the free flow cat from Downey). I called Downey to inquire
> about this "probe", and they had no idea. So it's now in a sandwich bag
> ty-wrapped to my frame. Any ideas?????

This is a temperature probe used to turn on a dash light in the even the
CAT gets too hot, like if the fuel mixutre goes very lean for example.
This was from the early CAT days, before much was really known about
their function.

> My engine also has the air-injector thingie over the exhaust ports, but
> is not compatible with the cutouts in the header, so I blocked them off,
> and the injector thingie is also ty-wrapped out of the way. Any ideas???
> Downey was also equally clueless.

If this is not requred in your area for smog legalness, why not just
eliminate the entire AIR system (pump, hoses, manifolds, etc.)? Downey
is just "clueless" because they don't want to possibly direct you to
illegally tamper with your vehicle's emission control system.


> The guy I bought this truck off of in California said his wife worked for
> Toyota in 1980, and got a big discount when they purchased it, so they
> picked it up, literally, "right off the boat". Could I have some sort of
> Japanese hybrid somethin somethin???? Also, my VIN doesn't seem to
> match the types I see on the gear ratio page, it's RN47025xxx.

Naw, this is a U.S. spec. vehicle for sure. Did you try looking at the
axle code on the data plate under the hood on the firewall?


Jim Brink

------------------------------

Date: Wed, 06 May 1998 16:59:48 -0700
From: Jim Brink 
Subject: Re: NOx emissions

Ed.Wong@astramerck.com wrote:
> 
> Jim:
> 
> Well, parts of PA now has a "dyno" test for emissions....
> 
> My 22RE equipped truck has now failed twice for NOx levels
> 
> Limits:
> HC - 0188
> CO - 01.69
> NO - 1300
> 
> First Test:
> HC - 0032
> CO - 00.27
> NO - 1461
> 
> Ok - so I reset the timing to stock (it was advanced by +10 deg over stock),
> filled the tank with Sunoco 94 (which I usually run anyway),
> checked the idle - its set to stock specs.
> 
> Note that I run a Jacobs ignition, plugs gapped to 0.052 (have about
> 2K miles on the plugs), LC header, Borla pipes with a rather new
> Thrush muffler, Downey airbox, and a worn 22RE with 263K miles
> on the odo....
> 
> I had recently reset the mass-air vane using the Vf signal from the EFI.
> I reset the signal to "base" - what is should be. I actually went "leaner"
> by 12 notches - not surprising that the spring had weakened over 9 years!
> 
> Second Test:
> HC - 0043
> CO - 00.15
> NO - 1625
> 
> They guys at the shop I use don't really know what to do (they take it
> to another shop for the dyno test) - its really a Ford dragster fabrication shop
> and not a "tune up joint".
> 
> The engine is sound and runs strong - any thoughts on what to look for next?

Ed, I would concentrate on the EGR system first but you are on to
something with the mass-air adjustment. Looks like you went a bit too
lean, judging from the HC readings rising a bit from the baseline. Not
that it drastically increased the HC enough to fail, but one cause has
an effect on another and so on...

Start by fattening up the idle mixture a bit. Don't go too far though.

Next, check out the entire EGR system. Is this the original EGR? Are you
familiar with the vacuum test for EGR? Using a vacuum pump, apply vacuum
to the EGR and see if the RPM drops or the engine stalls. If, not, pull
the EGR and check the passages. It is a good bet that the passages are
blocked or there is a build-up of carbon on the pintle inside the valve.
If it is too far gone, replace the valve. Also, the EGR vacuum
modulators have a pesky habit of dying (internal spring gets weak) or
the little filter gets clogged in the cap of the modulator. I wonder if
on one of your retests the shop will let you bypass the modulator to see
if the problem is a restricted vacuum supply to the EGR through the
modulator.

Make sure the timing is set to spec. Over retarded timing will kill you
in NOx.

You are not that far off. Try these steps and let us know what happens.
(Note: HC is measured in parts per million-PPM-, C0 in percent, and NOx
in grams per mile- g/pm).


Jim Brink

------------------------------

Date: Thu, 14 May 1998 09:42:34 -0400
From: Ed.Wong@astramerck.com
Subject: emissions

> My truck (1985 22RE) just failed its emissions test.

HC problems are usually
   - O2 sensor
   - possible leaky injectors

NOX problems are usually EGR related?

EWong


------------------------------

Date: Thu, 28 May 1998 14:51:58 -0400
From: Ed.Wong@astramerck.com
Subject: Emission Woes continued

Ok - by now you know that the Philly area only (the 4 counties
around Philadelphia) are using a 15mph dyno test to check
emissions...

              HC          CO         NOx
limit        188         1.69       1300
test #1       32         0.27       1461
test #2       43         0.18       1625
test #3       86         0.38       2193

Well - as you can see, I still failed, but I got a sticker
because I spent $150 on
   EGR valve (probably was OK)
   Dash pot (it was actually sticky)
   Fuel Filter (had the tranny out - its real
      easy to change the fuel filter when the
      tranny is out!)
   Throttle Gasket ( I had to take the throttle off
      to install the dash pot as the screws were stuck.
      I cleaned up the throttle while I was there)

Test #1 was my normal +20 deg advance
Test #2 was with the timing reset to stock: +10 deg advance
Test #3 was with the above parts and the advance dialed to +15deg

It may also be due to the stretched chain - cam timing is off?

anyway - I now have a sticker. It does say "wavier" on it and
now that I noticed that - I saw a few cars in the lot that had
"exempt" sticker on them - less than 5K miles/year or some
other exemption

EWong

------------------------------

Date: Thu, 28 May 1998 12:15:41 -0700 (PDT)
From: Ken Emanuel 
Subject: Re: Emission Woes continued

I really don't like seeing such a variability in the emission test data (see
below).  As I mentioned 2 weeks ago, my truck was tested twice in 30 minutes
at two separate shops (I won't get into it) and the results of the tests
varied quite a bit.

Your timing was set to 3 different timing settings: 10, 15, and 20 degress BTDC.
Test #3 yielded the highest NOx levels with the middle timing setting (15
deg.) AND a new EGR valve, Dash pot, Fuel Filter, etc., not to mention new
plugs, wires, etc.  Anyone else seen such variance in emission results?
I do believe that the factory specs for static timing is 5 deg. BTDC. Are
you setting your timing statically or dynamically?  (Dynamic is shorting out
connectors TE1 and C in the "Diagnosis" black box under the hood.)

[big snips...]
>Ok - by now you know that the Philly area only (the 4 counties
>around Philadelphia) are using a 15mph dyno test to check
>emissions...
>
>                HC        CO          NOx
>limit         188         1.69       1300
>test #1        32         0.27       1461
>test #2        43         0.18       1625
>test #3        86         0.38       2193
>
>Well - as you can see, I still failed, but I got a sticker
>because I spent $150 on EGR valve, Dash pot, Fuel Filter,
 and Throttle Gasket 
>
>Test #1 was my normal +20 deg advance
>Test #2 was with the timing reset to stock: +10 deg advance
>Test #3 was with the above parts and the advance dialed to +15deg
>

------------------------------


------------------------------

Date: Fri, 12 Jun 1998 14:48:12 -0400
From: "Dr. Karl Bellve" 
Subject: Emissions

Well, after installing a new EGR valve, truck still fails on HCs at a
second emissions station.

Here is what my truck has gotten:
wires
plugs
distributor cap
distributor rotor
O2 sensor
EGR Valve
Throttle body sensor adjusted
Throttle body cleaned
3 gaskets for throttle body and EGR valve.

This puts me way over the $100 to qualify for a waiver. I will be doing
the next phase of the waiver, which is getting an estimate to get it
passed emissions (which must be >$100). My truck hates going to dealers,
since they might screw it up. Todays test did give me another 20 days
since I paid $15 to a new station. I did look over the vacuum tubes for
leaks but I didn't find any other than the EGR valve allowing fresh air
to be drawn in. I am thinking it might be a leaky fuel injector (or a
bad spray pattern) or, excess heat from the exhaust header (maybe
exhaust insulation is in order). Could it also be air leaking via an
injector seal? They seem to be fairly old too. Truck does a minor
roughness to its idle and does seems to slightly backfire during
deacceleration.


At least I was able to throw in some hex head screws for the throttle
body sensor as Ed suggested.

Cheers,

Karl Bellve

------------------------------

Date: Sat, 13 Jun 1998 17:01:57 -0400 (EDT)
From: "Karl D. Bellve" 
Subject: Re: Emissions

On Fri, 12 Jun 1998, Brandon Miller wrote:

> stick a bb in the vacuum line before the egr ( it will by pass it for smog,
> sort of defeats the purpose but I have seen it work.....)


I don't think it is the EGR valve since I replaced it and the new one
seals fine. I don't think the EGR valve was opening at idle since I can
kill the engine by opening the EGR valve at idle. On a side note, my
Hydrocarbons has increased after replacing the parts (from ~440 to 700+).
I am thinking that I am cutting off the extra unmetered air and now the
excess fuel isn't burning. Excess fuel perhaps from leaking injectors.

------------------------------