Here's a list:
CO Failures (fuel injected vehicles)
1. Any of the computer components listed above.
2. Leaking or bad injectors.
3. Mass air flow sensors (voltage or frequency being too high).
4. Fuel pressure too high (restricted fuel return line or stuck fuel
regulator)
5. Ruptured fuel regulator (fuel leaking directly into intake)
HC Failures (all vehicles)
1. Engine was not at normal operating temperature.
2. Ignition system malfunction. Spark failing to occur for any reason
will send unburned hydrocarbons (HC) down the exhaust pipe. Example: bad
plugs, plug wires, distributor cap, rotor, coil wire, coils, etc.
3. An extremely lean fuel mixture that causes misfiring. Examples
include disconnected, leaking or misrouted vacuum hoses, intake gasket
leaks, EGR stuck open, low fuel pressure.
4. Over advanced timing. Insufficient spark duration.
5. Low compression or mechanical problems. Worn rings, burned valves,
bad or misaligned timing gears.
6. Over rich fuel condition causing both HC and CO failures.
7. Contaminated, bad, or restricted catalytic converter.
Nox failures (all vehicles)
1. Improper operation of the EGR valve. Stuck open, obstructed, leaking,
or misrouted EGR vacuum lines.
2. Plugged EGR passages. Carbon build up in passages.
3. Over advanced timing.
4. Too lean of fuel mixture.
5. Engines cooling system in poor condition, causing excessive
temperature.
6. Malfunction of the electronic spark control (ESC), and knock sensor.
Computer fails to retard timing.
7. Contaminated or bad catalytic converter.
And then...there's just the bad design.
- Bernd
-----Original Message-----
From: owner-dakota-truck@buffnet.net
[mailto:owner-dakota-truck@buffnet.net] On Behalf Of Ryan G.
Sent: Sunday, January 13, 2002 2:13 AM
To: dakota-truck@buffnet.net
Subject: DML: Re: cat/o2
rather than replacing cat after cat after cat what needs to be done to
aleviate this problem? What is the cause of failing cats?
----- Original Message -----
From: <THRASHER949@aol.com>
To: <aol@dakota-truck.net>
Sent: Sunday, January 13, 2002 1:44 AM
Subject: DML: cat/o2
I also have been threw 4 cats and I just hit 40k miles. However, my last
cat was a car sound. (I work for car sound) However once again, the
problem is that the exhuast gases are getting so hot that it burns away
the matting, leaving the brick inside able to move and beat its self to
death. We are currently working on a prototype this week of we get time.
We are going to stamp the shell of the converter with ridges deeper than
normal so exhuast gases flow directly through the brick and do not blow
against the mattting deep in the ridges. My carsound converter took
14000 to blow instead of the usual 8000 or so from dodge. If you replace
yours with a car sound, keep the old cat in a box. Thats what I did and
my dealership (Tustin Dodge) was willing to still warrenty my converter.
-Jeff
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