high HC emissions problem

[behlinla]

If the exhaust leak is after the O2 sensors, then it shouldn't any effect on the emissions. High HC is basically a fuel/air problem or caused by a lack of proper combustion.

You can determine which transmission you have by counting the bolts or looking at the code on the door sticker.

[dfordg]

I replaced the spark plugs in mid-October. The ones I pulled out were pretty worn (excessive gap width). Looks like there was also some overheating.

The transmission pan is labeled "AXOD Metric" and the door sticker says "XFFYY", so I guess it is an AX4S .

[dfordg]

Here's what came out of the most recent test. It didn't pass, but it did better on the HC. He marked "missing catalytic converter" on it, but he didn't see one of them which I showed him after the test. There might be something to this though as the setup at the Y-pipe doesn't look like what I have in the shop manual. It's possible something was changed at some point in that past and that there's just one working cat. I got this stuff "Cataclean" but didn't use it as they recommend using it 7-10 days before the test. At least it's no longer a GP.

[behlinla]

Besides failing emissions, does the car run well? Smooth idle, good throttle response and revs well with your foot on the floor? Fuel economy okay? Is it trouble-code free?

If the car runs fine otherwise, it's very possible the catalytic convertors are bad or somebody hollowed them out. The fact that you have an exhaust leak at the Y-pipe seems to support the fact that the exhaust's been messed with.

[Jeff K]

If PFE sensor is melted or hose from exhaust to PFE is melted, suspect clogged cats.

PFE sensor is a fairly common failure point, especially of the car is driven on lots of short trips in cold weather.

[dfordg]

Originally Posted by Jeff K

If PFE sensor is melted or hose from exhaust to PFE is melted, suspect clogged cats.

PFE sensor is a fairly common failure point, especially of the car is driven on lots of short trips in cold weather.

PFE sensor and tubing were replaced in October.

The real problem with short trips is that I don't think the thermostat/ cooling system is working well, so the engine doesn't really warm up to optimal temperature. I think that this could be a part of the cat functioning problem.

[dfordg]

Originally Posted by behlinla

Besides failing emissions, does the car run well? Smooth idle, good throttle response and revs well with your foot on the floor? Fuel economy okay? Is it trouble-code free?

If the car runs fine otherwise, it's very possible the catalytic convertors are bad or somebody hollowed them out. The fact that you have an exhaust leak at the Y-pipe seems to support the fact that the exhaust's been messed with.

I haven't tried rev'ing it past 3K rpm, either in park or on the road. It idles at about 750rpm. There is a transmission problem (skips 2nd gear) and this I believe causes a fuel economy problem. But it passed emissions 2 years ago with this same problem. The fuel pump could be on its way out, but I've had a car pass in CA with the fuel pump at the same stage. I know that there was some work done on the fuel rail system 2 years ago. It has as I mentioned, that code 452, but it's only in continuous memory and doesn't throw a CEL. One thing I've noticed recently is apparently a loss of power. It's intermittent but quite noticeable when it happens. It's hard to get it past 45mph on an incline.

About the Y-pipe, I would say that there is no leak when it's fully warmed up. I should be getting more info on this soon, but what I would guess happened is that this was originally a non-CA car, and somewhere along the line someone replaced the original Y-pipe with a Y-pipe from a similar but not identical Taurus/Sable, and so the setup of the cats is different. I guess these 1995 models have various minor difference so I don't know for sure at the moment.

[behlinla]

Originally Posted by dfordg

One thing I've noticed recently is apparently a loss of power. It's intermittent but quite noticeable when it happens. It's hard to get it past 45mph on an incline.

This can be a symptom of a clogged exhaust, especially if you let off the gas suddenly and you hear or feel a wheezing or whoosh sound. Your mechanic should do an exhaust back-pressure test. He could also diagnose it with a vacuum gauge if he knows how to interpret the readings (most older mechanics are very familiar with vacuum gauges).

[dfordg]

So the vehicle passed CA emissions on Thursday, one day after a new Catco catalytic converter installation. The numbers are attached. I took back the Cataclean and ran about 1/2 bottle of GTP (Guaranteed to Pass) through the system a couple of days before the test. I also replaced the front O2 sensor with a new Standard/Tru-tech sensor I found on Ebay. Don't know if any of that made a difference compared to the new converter. I didn't do an oil change, so maybe some HCs came through from the old oil. It's the first time I've ever seen 0 ppm NOx.

[behlinla]

Those are good numbers! A working EGR system and catalytic convertor do a really great job of reducing NOx emissions as you can see.

Have you noticed an increase in power? Can you get it past 45 mph on the incline?