03 Rio Cinco problems and a couple solutions
Hi. I'm new to this forum. This is my 1st post. I'll do my best to make it short.
I picked up my 03 Rio Cinco 5 speed, 157K miles, one-owner car (retirees from Maryland to SC) almost two months ago after my 99 GMC truck started shearing teeth off the flex plate. My wife has a '15 soul, so when I saw the Rio I jumped on it.
The first week I had it was awesome. Its not the fastest of cars, but with only 1.6L....meh. Literally, day 8, I picked my son up from school. About a mile after we left his school, I'm waiting at a red light and it just starts shaking, running rough. I gave it some gas and it seemed to correct itself. It was fine the rest of the way home. The next morning it did it again, twice, then a few times on the way home. Waited an hour and let it cool off. Found a couple spark plugs that had some gnarly build up. Put those same spark plugs back in just to see....it started up just fine and ran great til I got to the parts store for some new economy plugs and a bottle of gas treatment. The gage was showing half a tank so I just poured it on in.
No problems til the next afternoon. The shaking thing happened a couple more times and then it didnt stop. Of course the engine light came on. I've seen this before....ignition coils. Luckily I was only a couple miles from home at this point so I just chugged on.
Once I got home, it gave me P0300(random multiple misfired), P0302(cyl 2 misfire), & P0303(cyl 3 misfire). I found a reman coil set online, shipped to my door for about $40. While I waited for my part to arrive, I did some research about my Rio. Eventually came across this forum. I read most of every thread and put together some useful stuff in my head that really helped me think through what was to come.
The "new" coil packs came. Got them on and took it for a test drive. It ran great. It had some pep to it....for about 15 minutes. Chugged back home. It gave me a O2 sensor code (bank 1 sensor 2) this time. I took out the O2 sensor, cleaned it and put it back. Seemed to do the trick...for a few hours. I found a new sensor online relatively cheap. I came back to the forum and re-read some more. After a new O2 sensor and another failed test drive, I got cylinder 2&3 misfire again. My neighbor is the electrical/HVAC tech where he works, so I got him to come over and check out the electrical system. While he was checking the ignition, his timing light was strobing. He looked at me puzzled. I told him about the wasted spark thread. After thinking for a few minutes he understood why. Each of the 2 leads is sending 5V to its corresponding coil, so both spark plugs fire simultaneously. Those connectors lead back to the fuse block, then to the ECU, so the ignition is directly fired by the ECU. The only thing between is a fuse and a relay. Hopefully that will help someone.
That was not the problem with my Rio, but it is good info.
Took the time to clean the injectors, replace the fuel filter, fuel line flush, pressure test, ran down the fuel lines to check for any leaks, beat my head against the wall, did some more research. I came across a video where a guy had crumbling ignition connectors. They literally fell apart when he squeezed them to pull them from the coil packs. I realized that mine were new....hmmmm.
I went and unwrapped the nicely taped wires back to the butt splices. The butt connectors for lead 2/3 were a couple gobs of melted plastic. Lead 1/4 were a couple of beautiful blue butt connectors with the usual "AWG" printed down the length. That "Aha" moment....Someone did a tune up on this car before I got it and wired the connector backwards ( 1 positive wire, 1 negative wire).
That seems to be the issue. Ive had a couple O2 codes pop up that didnt seem to effect driving. I disconnected the battery for a minute both times and the codes cleared. And had to clean the TPS. It had a bad dive shifting into 2nd. I did it the cheap-o way. Propped open the throttle with some blue shop rags and sprayed carb cleaner. I let it air out over night. While I had the air cleaner off, I hit the MAF with some cleaner. I'll probably get an other TPS in a couple weeks. I need to put some money back in the bank first. Hope this helps someone. Thanx