dso

my mom drives a 99 accord and the check engine light went on, and she went to honda to get it checked out. While at honda they told her that it was her cat that was causing the light to come on and that she would need to get it replaced. Now here is my question, they told her that if she didn't get it fixed (which they said was $900) that it could cause engine damage... or am i wrong?

The only reason why im asking is because when i had my civic there was no cat it was just a straight pipe and my engine ran fine. is this because it was a civic or was i just plain stupid and really was hurting my engine?

thanks for reading, if you did.

Andyman395

the engine light is probably on because there is a o2 sensor before and after the cat. the 2 o2 sensors tell the computer the percentage of o2 entering and exiting the cat. if that ratio is out of spec it will throw a trouble code. that is caused by the catylists in the cat being burnt up. it shouldnt do anything to the engine.
as for your civic, people with tell you that having no cat will burn up your exhaust valves because of lack of back pressure but that is a load of crap. the only problem you can get from that is a loss of low end tourqe do to overscavanging of the cylanders. (but you should get some high end)

YeuEmMaiMai

if you run without a cat your gas milage will go down the crapper

dso

lol yea, that's all my civic was anyway (highend). but thanks for responding. so i should just tell my mom not to worry about it then huh?

A_Rotary_Guy

Yes, a bad cat can cause engine damage. Have you never seen a catalytic converter get plugged before? We had a Dodge Durago at work that came in because it was running rough. We had it idling in the shop for a bit and started smelling this weird burning smell. Looked underneath the vehicle and the cat was glowing red hot. Took it off the vehicle and the catalyst honeycomb material had broken loose and plugged the exhaust. Obviously this is very very bad and would cause engine damage. Btw, the 2 oxygen sensors (one before the catalytic converter and one after it) do monitor the amount of oxygen in the exhaust, but each has a seperate function. The first oxygen sensor is the one that is used to adjust the air/fuel ratio according to the amount of oxygen in the exhaust. The second oxygen sensor uses the read-outs of the first sensor in conjunction with the read-outs of the second sensor to see how efficiently the catalyst is functioning. If the computer believes that the catalytic converter is not performing it's job well enough, it will throw a CEL. The O2 sensors can also throw codes because they themselves are bad, so take this into consideration too. Also, if you live in an area with emissions testing, good luck passing without a cat.

sony224422

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by A_Rotary_Guy &raquo;</TD></TR><TR><TD CLASS="quote">Yes, a bad cat can cause engine damage. Have you never seen a catalytic converter get plugged before? We had a Dodge Durago at work that came in because it was running rough. We had it idling in the shop for a bit and started smelling this weird burning smell. Looked underneath the vehicle and the cat was glowing red hot. Took it off the vehicle and the catalyst honeycomb material had broken loose and plugged the exhaust. Obviously this is very very bad and would cause engine damage. Btw, the 2 oxygen sensors (one before the catalytic converter and one after it) do monitor the amount of oxygen in the exhaust, but each has a seperate function. The first oxygen sensor is the one that is used to adjust the air/fuel ratio according to the amount of oxygen in the exhaust. The second oxygen sensor uses the read-outs of the first sensor in conjunction with the read-outs of the second sensor to see how efficiently the catalyst is functioning. If the computer believes that the catalytic converter is not performing it's job well enough, it will throw a CEL. The O2 sensors can also throw codes because they themselves are bad, so take this into consideration too. Also, if you live in an area with emissions testing, good luck passing without a cat.</TD></TR></TABLE>

this is true.

Dodge has a problem with there OEM cats breaking up and plugging on magnum engines. I had the same problem, i was towing my 5200 lb+ boat when my gf told me her feet were getting really hot. me thinking wtf i really am feeling the load of this boat, it felt the same as towing with my fathers 305 heh, i get out and look under and my cat is orange and the heatshield is red. took a sawzal and make a nice little slit in front of the cat and bam restored the power until i could replace it.


However, 900 is way too much, buy either a direct fit or a universal one and have an exhaust shop weld it in or put it in if you can't. shouldn't be more than $300.

pos_cd5

i have also heard of rare cases when the cat gets plugged and causes the motor to overheat and opens the opportunity for damage to be done. as far as replacing the cat goes, the tree-hugger in me says go with a OEM one because they are much more efficient than aftermarket units due to more active ingredients (platnium and this other thing i cant remember the name of). but the realist and min. wage worker in me says get a $100 aftermarket cat and call it good.

TheMuffinMan

iTrader: (1)

I believe the most recent SE-R's had cat problems that would trash the engine?

sony224422

i forgot to mention, if it is plugged for too long, damage can happen, you can burn up the last piston in the firing order, atleast i know thats true for the dodge magnum engines.