After doing some repairs this weekend I came across some surprises. I started a few other posts. One being about a intermittent sputter. The other about the CV axle on the drivers side. I also soldered in a EGR plug from a scrap accord (green wire on my car was broken at the plug end, engine side) and it did nothing for the sputter.

As I was replacing the CV axle I decided to also change the oil while the car was already in the air. I noticed the catalytic converter has been removed (by P.O.) and there is no secondary oxygen sensor. I'm under the impression that this is where my intermittent sputter comes into play (but I'm sure my EGR plugs still need to be pulled and cleaned out). The car has a header installed and it does have a oxygen sensor in it. 4-2-1 setup. I noticed the downpipe that goes from 2to1 has a oxygen sensor bung that is plugged by a bolt. Is this where the secondary oxygen sensor should be installed? I am not seeing an empty o2 sensor plug hanging anywhere. I realize there should be a "cat" but I dont see it in my future to hack into a exhaust system that isnt rusted yet. I did throw a code the other day. I believe it was a code "43".

What do you guys think?

 

A 93 doesn't have a secondary O2 sensor.

 

And the code and the "sputter" sound related....just me?

 

I can tell the fuel pump is working. I can hear it "hum" every time I turn the key on. The car idles fine and has never failed to start (in the 2 week window I have had it).

I pulled the vacuum hose off the fuel pressure regulator and I didn't see gas. Maybe I can get another fuel filter and try that. I just hate to start throwing parts at it blindly.

 

I'm never a fan of throwing parts/money at an issue. So first do not not touch the fuel filter.

Now, I will now call myself the "kettle" and say replace the O2 sensor. Suggest a Denso sensor that can be had online for ~$40. Be sure there are no exhaust leaks before the O2, if none, replace the O2 and lets see what you have from there. I'm playing the odds, 9 out of 10 time the code 43 is an issue with the O2 and a lazy/bad O2 can causeall kinds of issues...."sputter".....assuming the tune up items are up to date.

 

Thanks poorman! I also started leaning towards the o2 sensor last night after reading multiple threads. I'm quite certain the header don't leak at the head. It was leaking between the header and downpipe when I got it (EX style 2 port gasket). I pulled it apart and removed the 1/2 of a gasket that was in there then put it back together without a gasket...it's a lot quieter but I'm sure there is still some leak. But, thats after the o2 sensor since my o2 sensor is mounted in the header. A new gasket will be installed once I figure out this funky problem. I think I'll pick up a o2 sensor tomorrow and see what that does.

 

If it's leaking at that connection, it's not too far away from the O2 sensor. That sensor actually measures the oxygen DIFFERENCE between inside vs. outside. So exhaust gas blowing onto the outside of the sensor can throw off the measurement.

According to the parts drawings, a 93 LX should have a 4-into-1 manifold, with just a single pipe under the oil pan. PO swapped the exhaust manifold for one from a 93 EX? The EX car would have it's only O2 sensor down below/behind the oil pan where the 2 pipes join into 1.

You might improve things by moving your O2 sensor down there to the location where it should be in an EX car. That means splicing & fastening the wires down to that location.

 

Correct, the LX "should" have the 4to1 setup. It has an aftermarket header installed and I assume a downpipe gasket for a EX model would fit the current application. There is a o2 bung further down the line in the downpipe so I could always relocate it.

 

Right. I'm not real certain about this, but some of the issues might come from the O2 sensor reading only 1 or 2 cylinders. Might be better if the O2 sensor was located after all 4 mix together.

If it's an aftermarket header, it might need "its own" kind of gasket rather than the stock EX gasket. Maybe 2 little metal-O-rings vs something that looks like a gasket.

 

It has the same shape as the EX exhaust manifold flange. When I had it apart, I can say that both mating surfaces are flat. There is no valley for an o-ring style gasket. Might just get my hands on the right gasket and see where that leaves me with the issue.