I did some more checking and it seems that the cat converter is bad or
not doing a complete job of cleaning HCs and Nox.
I did the vacuum test at the intake manifold and @ idle it's 19"/hg
when I raise the throttle quickly it goes to zero, if I raise the idle
to 1500-2000 rpms gradually the vacuum goes up about 4"/hg but in about
20-30 seconds drops back down to 19"/hg. There may be a plugged up
converter that is causing this, right?
I let it warm up for around 20 minutes and did a temperature test on
the front and rear of the converter. There is only a 25oF difference,
not the 50-100oF that I'm told by the Magnaflow Tech it is suppose to
have. Also, I may not of got it hot enough because the two temps were
275/250oF.
When I asked the Walker exhaust tech he said that the temp test was not
that accurate nowadays because of changes to the core materials.
The Dodge converter was 20" long and heavy. The Magnaflow is 12" and
7lbs. I called Walker Exhaust and they have a longer heavier unit and
their brick is 13" whereas the Magnaflow was only 6". Total length of
the Walker # 15042 is ~ 18-19" Anyway my NAPA store has it in stock
and @ $110 with my AAA card (10% off)
Warranty of the converter at Walkers is 25k miles or two years, I
believe the others are a lot less, 6 months or something like that.
I haven't tried it yet but there is a site www.smogtips.com that is
suppose to have tech feedback via email.
Just looking back at my old smog test results and at one time the HC
was down to just 1 PPM for HC. When I'm standing next to the exhaust
pipe, I can't smell anything abnormal. When I drive on the freeway I
can smell other cars with pollution and that's mainly when traffic is
in gridlock, which we have a lot of.
I hope to get it back up to the 18mpg it once had. Last tank I got
12.6mpg and driving was 25% in the city and rest on the freeway.
I have a vac pump and I'll check the EGR valve but don't expect it to
have problems sine I last replaced it. Just checked the price at NAPA
and they said $115. ouch!
My ignition stuff looks OK by just looking how the plugs are burning
the fuel. Which is a nice lite tan and clean porcelain and clean
electrodes - using Autolite platinums. Do they get good or low mpg's?
This is OT but does a lap top PC Oscilloscope converter or adapter
exist? I was looking at a very nice SW/HW $200 OBDII Scanner from
Autotap.com but want it to be useful for OBD 1 also. Btw, they have a
great tutorial on Sensors.
Going to NAPA now . . .
Ron in Kali
===============================================
Re: Re: 94 Dak 5.2L Cat Converter Air Pump or Air Switch Valve?
From: Biff Byrum (bbyrum9@foothill.net)
Date: Fri Sep 28 2007 - 16:10:26 EDT
I'm sorry, I'm stumped. You seem to have done everything that you could
that
applies to the problem. Try plugging your question into a a good search
engine and finding a forum where you can talk directly to pro
mechanics. I
know there are several free ones around.
Your EGR should not be the cause, and no, 11 to 15k is well within it's
operating life. But if you can get ahold of a vacuum pump, test it
anyway.
Do the one test with the engine running, 3 to 5 in. maximum to affect
engine
speed. Then with the engine stopped, put 15 in. on the EGR. See how
long it
holds that, it must not begin leaking down immediately. If there is
something wrong with it, it was likely defective to begin with.
I agree you should to the CAT temp test. And yes, Kalifornia has been
"adjusting" the pass values for years. I had proof of that back in
1988. But
try to get CARB to admit to that.
One thing a good smog mechanic will do first is to pull the codes. They
don't all set the light, but if they have occured in the last fifty key
cycles, they are stored in memory. One other thing is to prod the O2S
with
the Snap-On meter. It gives him the values right on the screen that
it's
returning. Should be 0.2 to 0.8 volts constantly varying back and
forth. And
it should pass the 0.5 volt line so many times a second. I put one on
my 95
a few years back and it just plain shorted out. It was returning almost
line
voltage to the PCM.
By the way, I've been told that you should consider maximum service
life on
both EGR's and four wire O2S's to be around 80K. Keep us informed,
there's
lots more of us who could end up in the same boat in the near future.
We
don't all just recycle our Dak's every 60K. Biff
----- Original Message -----
From: "rws" <rwsam2002@yahoo.com>
To: "DakotaTruck DML" <dakota-truck@dakota-truck.net>
Sent: Thursday, September 27, 2007 2:36 PM
Subject: DML: Re: 94 Dak 5.2L Cat Converter Air Pump or Air Switch
Valve?
>
> Biff,
>
> Oil and filter was changed. Using oil branded for "older" vehicles. I
> think they put some copper in the oil to keep it running quieter, but
need
> to verify.
>
> New O2S.
> New ECT sensor.
>
> Used Chevron's injector cleaner just prior to test, about a month
ago. a
> BMW dealer says its the best they found to keep injectors running
clean
> not dripping and remove the built up carbon on pistons and valves.
>
> PCV valve cleaned and checked and I can hear it making noise with
engine
> running. Shop manual says this is a good sign.
>
> The EGR valve was replace 2-3 yrs or 11-15k miles ago. Maybe low oct.
> fuel can make it dirty again? I don't know. I tried to clean the EGR
> with solvents befor getting a new one. They are hard to clean so that
> they shut completly and smoothly, that's why I just got a new one.
How
> long should they last?
>
> If I give up and take it to a CA certified smog mechanic, what will
he do?
> Anyone here in California? Have you noticed the smog test criteria
for
> the three elements gets lower the older the vehicle is?
>
> Ron
> -----------------------------
> Re: 94 Dak 5.2L Cat Converter Air Pump or Air Switch Valve?
> From: Biff Byrum (bbyrum9@foothill.net)
> Date: Thu Sep 27 2007 - 16:54:30 EDT
>
> Yeah, I had about the same results. Just passed by one. It's said
that
> leaky injectors and the O2S are the leading causes of HC failure.
>
> Excess carbon buildup in the chambers can cause this reading. Someone
> sugested B-12 Total Combustion Chamber Cleaner. Also suggested was
> changing the oil so the new oil can absorb more HC. Remember that you
do
> have that silly, prone to fail EGR on that engine. Also, new PCV
valve?
> Biff
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