azhatch

My friend has a 98 civic dx coupe, he just recently put headers on it and is running without a cat, he also has greddy evo for exhaust. Is this a good thing? he is blowing a noticable amount of smoke out of his tailpipe. whats the problem?

hybridreams

When's the last time he had an oil change?

azhatch

he changes it every 3k, I thought it wasn't a good idea to run without a cat if you don't have any forced induction, no backpressure.

rodrez.

He probably won't see that much power w/out the cat, because it doesn't sound like he has too much under the hood. He should bolt it back up, and see if that solves it, plus he's throwing out all that pollution for about 1 or 2 horsepower.

hybridreams

maybe his piston rings are bad. how hard does he drive it? try a compression test.

azhatch

the question I have is, Is it good to run a stock car without a cat?

00-ITR-373

This shouldn't make a diff, but did he use a different exhaust gasket (the donut one)... I think you need a larger one. Again, sholdn't matter, just asking.

Halo

Are you throwing a cel? It could be that whoever installed the header didn't screw the 02 sensor on tight enough or it is time for a new one? If the timing is too retarded or the fp too high you will run rich. compression test all four cylinders if they have similar numbers across it is unlikely to be rings.

Halo

Wait if your friend is running a stock 98 sohc non vtec and ecu and is blowing smoke then most likely one of the two 02 sensors isn't plugged in and is in limp mode, where the car automatically switches to rich

LSturboHB

oil shouldn't have anything to do with BLACK smoke.
Blue smoke= oil
white puffy smoke = water
and BLACK is running rich, usually. OR a large amount of carbon.
Was the header new ? i have put header on and they will smoke/ burn off any crap that was inside. What other mods does he have ? look into a A/F gauge and see what the levels are at

LSturboHB

Thats correct.

azhatch

he has a dc sports 4-2-1 two piece header for an ex model on a dx. it bolted right up to the exaust with no problem. the only thing is that the car runs two o2 sensors but the header has a mount for only one.
will there be a problem if he ran it rich for a long period of time?
also, will running rich hurt his power?
he does have only one o2 sensor plugged in and the other is unplugged and removed from the car. if he left it plugged in but not mounted in the exhaust will that chang anything?
thanks

EVIL Hx Coupe

I have a 96hx, and im running a header with only one o2 hole, so i have one unplugged like ur friend.... I dont see anysmoke coming out of mu exhaust though. But still I wonder if it hurts anything to run without an o2 sensor.

azhatch

he does use premium pump gas (about 90 octane) every time he fills up. also every time he gets his oil changed, he adds a bottle of shogun fuel system cleaner.
he changes his oil around every 3000 miles. also he does have the stock spark plugs and stock ignition wires since he bought the car new in july of 98. he now has 73,300 miles on it with the stock plugs, he needs to change them. he is also using the factory exhaust manifold gasket. he does have a copperseal one from mr gasket that he has not yet installed.
do you think that he should switch o2 sensors and see if that helps.
right now he has the one that is installed in the cat (in the stock position) in the header. would it make a difference if the o2 sensor that is suppposed to read off the header(in the stock position) was hooked up instead.

sammysnakes

headers are not going to make much of a difference on a stock dx engine. just put the stock headers back on and leave the exhaust. if it continues to smoke get a compression test, you might need new rings.


[Modified by chainsaw, 10:08 PM 6/24/2002]

98akcivic

should i get new plugs and wires, they are the stock ones.

lilxvtecxpwr

maybe its blowing out black smoke because he has no cat.....