Questions and Answers

Kia Sephia Engine Misfire Q. Well I am 22 years old and just got out of the military. I never owned a car and it was necessary that I bought one. I had no luck at any of the dealerships because I had almost no credit history. I had to resort to purchasing a car from the classifieds. After searching with no promising results for a couple weeks, my parents 1995 Kia Sephia LS had died.

Turns out the rings were shot and oil was leaking into the exhaust. They were planning on scrapping it but I thought I would see if I might be able to find a engine from a junkyard instead. I got lucky and found a totaled 1995 Sephia with the engine in excellent condition (45,000 miles) and to top it off I could purchase it for $450.00. I new in advance from my father's experience I was in for it but for $450.00 I couldn't resist.

So now with the help of a neighbor I had installed the engine and replaced all the fluids, filters, spark plugs, spark plug cables, and even the front oxygen sensor. I was not finished there. I had planned on replacing pretty much the entire exhaust. I did some price checking with the dealer. I found out that for a new catalytic converter they wanted around $800.00. Screw them, I figured I might be able to find one elsewhere. In the meantime I knocked a hole through the clogged converter and the car runs great except for a miss. The miss only occurs when the car is between 0 and 25 mph and the engine is warmed up. I knew that I would hear a putt putt sound from the exhaust by knocking a hole through the clogged converter but I doubt it would have caused a miss.

I did some searching on the internet and managed to find everything I would need to replace the exhaust. I have a muffler and rear oxygen sensor already and I am waiting on the catalytic converter. Until I get the new converter installed I would like to leave the old muffler and sensor on because I am afraid I may foul the new parts out if I use them with my jimmy rigged converter. I think it is the rear oxygen sensor causing the miss because the check engine light is on.

I also understand that it would be kind of stupid of me to install more expensive NKG plugs until I work out all the car's issues so in the meantime I bought Champion plugs from AutoZone. I really don't care if I foul out these plugs because they were cheap. Eventually when I feel comfortable with the way the car runs I will put the NKG plugs in.

I even did the extra work of purchasing both car specific shop manuals from books4cars.com. I still will need the electrical troubleshooting manual since modern cars all use computers to adjust the engine. I have yet to find this manual.

I found out that Kia does not allow third party companies to produce matching parts and limits the distribution of their own. This makes it not only difficult to locate, but expensive to replace parts. I would like to make a suggestion to anyone to avoid Kia at least until they make their parts more available and affordable.

Anyway, here are my questions. Do you think that replacing the converter, muffler, and rear oxygen sensor will smooth out the engine? What else could be the problem? The sensor installs between the converter and muffler. It is a $200.00 part only available at the dealer. Can I test the car with the sensor installed to see if that fixes the problem without fear that the "unclogged" converter may damage it? Do you know where I might be able to find the electrical shop manual? Thanks for any help you can give.

Rich

A. There is a chance that the new converter and muffler will help the performance of the engine. Engines are designed to run with a certain amount of back pressure and by poking holes in the converter you reduce the back pressure. Will it eliminate the miss? I doubt it. A bad converter would effect the engine as a whole, not just one cylinder.

I would put the new parts in, clear the diagnostic codes and drive it to see if the light comes back on. If it does, drive it over to AutoZone and let them scan for the codes and see what they are. From there we can figure out what else needs fixing.

To get the codes yourself:

1. Locate the data link connector (DLC) at the top center of the firewall and short across the ENG. TEST and ground terminals.
2. Turn the ignition switch ON.
3. Start and warm engine, then run at 2,000 rpm for 3 minutes.
4. Diagnostic trouble codes are displayed as a series of long and short flashes on the MIL.

To clear the codes just disconnect the negative battery cable for a few minutes.