Subject: Re: [Shop-talk] High Hydrocarbons

From: "Karl Vacek" <[email-masked]>
Date: Wed, 28 Aug 2013 07:48:22 -0500

O2 sensors are pretty cheap, and I've changed the one on my '93 Suburban
every 50,000 or so.  Given the similarity of vehicles and years, I'm
guessing it's pretty much identical to the setup on your truck.  Suburban
almost always runs better with a new O2 sensor.  The sensor should be on the
driver's side of the Y pipe at the back of the engine - easy to get to under
the hood.  I think it takes a 7/8" box wrench?

As far as the cat, there's a YouTube video where a guy uses a gallon of
alcohol in half a tank (regular car - 10 gallons?) of gas and claims it
usually cleans his converter pretty well.  For harder cases he takes the cat
out and soaks it overnight in a bucket of water with regular laundry
detergent, hoses it out, and reinstalls it.  YMMV   ;-)

When my cat went out on the Suburban (at maybe 150,000 miles?) I replaced it
with a rebuilt original.  Passed emissions better than new - really - and
wasn't loud like the tiny Walker ones that cost just as much.  Still passed
easily till a couple of years ago the People's Republic of Illinois finally
stopped testing pre-OBDII vehicles.

Karl

-----Original Message-----
From: [email-masked]
Subject: Re: [Shop-talk] High Hydrocarbons

Is there a way to test O2 sensors?  I'm guessing the cat isn't poisoned
since it doesn't smell.  How do I check a crankcase rebreather?  This is a
91, so there is no OBD II Connector.
_______________________________________________

[email-masked]
Archive: http://www.team.net/archive

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From: "Eric J Russell" <[email-masked]>
Date: Wed, 28 Aug 2013 08:58:23 -0400 a=P2oOn6vrs4wA:10 a=8nJEP1OIZ-IA:10 a=S2wpYzp2RsyRkoRNwqcm1Q==:17 a=pw-q824V51wO40Jer7IA:9 a=wPNLvfGTeEIA:10 a=S2wpYzp2RsyRkoRNwqcm1Q==:117 reip=0.000, cl=1, cld=1, fgs=0

> Is there a way to test O2 sensors?

A working O2 sensor puts out 0.1-0.9 DC volts. This can easily be measured 
with a digital voltmeter (even my eL-Cheapo Harbor Freight voltmeter). With 
the engine warmed up (the sensor has to be hot to work), find the lead for 
the sensor. (There may be 3 or 4 leads if the sensor also has a heater built 
in.) Connect your voltmeter's positive lead to the sensor lead & the 
negative lead to ground. Do this leaving the sensor connected to the 
vehicle's wire harness so the computer will remain in 'closed loop mode' 
(receiving & sending signals). Thusly connected start the engine. Run it at 
2000rpm for a minute or two to make sure the exhaust & the sensor is fully 
warm.) At idle a working O2 sensor will be putting out an average of 0.5V. 
If the computer is in closed loop mode the measured signal will constantly 
vary as the computer richens/leans the mixture around the 'ideal'. If the 
reading is steady then the computer will usually assume the sensor is not 
functioning, ignore its signal and default to a pre-programmed fuel map - 
typically slightly richer than ideal.

If the sensor is more than 60,000 - 90,000 miles old it is likely at the end 
of its useful life. As they get old they get 'slow'. When it gets really 
slow the computer ignores it.

Eric Russell
Mebane, NC 

[email-masked]

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From: Battmain <[email-masked]>
Date: Wed, 28 Aug 2013 07:38:08 -0700 (PDT)

Pre_OBD II still had a diagnostic connector that you could short to see if there are any codes. (at least my cars did.)

Brian

>________________________________
> From: "[email-masked]" <[email-masked]>
>To: [email-masked] 
>Sent: Wednesday, August 28, 2013 7:02 AM
>(snip) This is a 91, so there is no OBD II Connector.
>(snip)

[email-masked]

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From: Michael Porter <[email-masked]>
Date: Wed, 28 Aug 2013 08:59:57 -0600

> Pre_OBD II still had a diagnostic connector that you could short to see if there are any codes. (at least my cars did.)

Pre-OBD, GM used what was known as the ALDL (Assembly Line Diagnostic 
Link), usually a 12-pin connector buried in the dash. Jumpering pins A & 
B initiated flash codes on the check engine light.

Cheers.

-- 

Michael Porter
Roswell, NM

Never let anyone drive you crazy when you know it's within walking distance....
_______________________________________________

[email-masked]

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From: David Scheidt <[email-masked]>
Date: Wed, 28 Aug 2013 10:10:57 -0500

On Wed, Aug 28, 2013 at 9:38 AM, Battmain <[email-masked]> wrote:

> Pre_OBD II still had a diagnostic connector that you could short to see if
> there are any codes. (at least my cars did.)
>
>
>
91 GM stuff sure did, too.  But it's specialized, and if you don't have a
tool, maybe not worth it.  It's pretty easy to monitor the o2 sensor
voltages, with a cheap (or not cheap, if you've got one) DVM.

-- 
David Scheidt
[email-masked]

[email-masked]

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From: "Karl Vacek" <[email-masked]>
Date: Wed, 28 Aug 2013 12:24:44 -0500

The connector is usually mounted somewhere under the edge of the dash near
the driver's right knee, though that location isn't guaranteed.  There
should be two adjacent pins on one end, and the connector will be missing
part of the separator between the two pins you want.  Short those two while
the key is ON.

A paper clip straightened into a long "U" works pretty well, and usually
it'll slip into place and stay there till you're finished.  One contact is a
ground, so you're not going to have an issue with accidentally grounding the
paper clip out while checking.

You count the flashes on the "Check Engine" light (called a MIL for
Malfunction Indicator Light in service publications).

The old GM standard was to flash 1 2 first, then whatever codes are set,
then end with 5 5.  It cycles through each code twice.  If all you get is 1
2 and then 5 5, there are no codes set.

A shop manual will usually give the codes, or Google them, or ask here.  If
nobody has the exact manual, I have a 93 GMC manual that should cover your
codes too.

-----Original Message-----
From:  [email-masked]
Subject: Re: [Shop-talk] High Hydrocarbons

There is a connector that my OBD II connector doesn't fix.  How do I 'short'
it to get the codes?
_______________________________________________

[email-masked]

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From: Battmain <[email-masked]>
Date: Wed, 28 Aug 2013 11:04:21 -0700 (PDT)

You'll probably need to dig a bit for the info for your particular car. The
connectors on my cars were over on the passenger side.  Normally it was a
three conductor assembly. The special (read expensive) J-tool to 'short' the
connector was a piece of conductive metal, which in my case was easily
replicated with a piece of wire. Then you turned the key to 'on' and any
stored codes were blinked at you on the dash. Kinda like blink, blink, blink,
pause, blink, blink, blink, blink, pause, then it repeated again. 

Brian
>To: [email-masked] 
>Cc: Battmain
<[email-masked]> 
>Sent: Wednesday, August 28, 2013 10:53 AM
>Subject: Re:
[Shop-talk] High Hydrocarbons
> 
>
>
>
>There is a connector that my OBD II
connector doesn't fix.  How do I 'short' it to get the codes?  

[email-masked]

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From: Benjamin Zwissler <[email-masked]>
Date: Wed, 28 Aug 2013 15:08:33 -0400

Some of the 80's GM cars would show the fault codes on the radio when you
put it in diagnostic mode, but you had to have the GM radio.  Not sure how
far into the 90's that persisted.

Ben.....

On Wed, Aug 28, 2013 at 2:04 PM, Battmain <[email-masked]> wrote:

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