Tune up problem!

I just got new parts replaced in my car and I thought it would run way better but it seems to run worse. I took it in to a mechanics shop that I new. I have a 1990 Honda Civic Si Hatchback and before I he replaced new parts it was running nice. The only problem was at high speeds after a while it would shake a bit and then the Engine light would turn on. He found out it was the O2 sensor. He has fixed other problems I had before and it made it better but this time I don’t know what happened. So this time he replaced my timing belt, O2 Sensor, Water Pump, Spark Plugs, Valve cover seals, and just cleaned around the new parts. He said it was very dirty and gross in side my block and other placed. When I got it back from him I drove it around and it felt REALLY sluggish. Its a standard. Normally it would jolt forward because it had a quick acceleration and I learned to control it well but now it has a fixes slow start no matter how hard or far I push down on the gas? Its a lot easier and smother to change gears because before I would seem my passengers gerk when I changed geara but I did see them do it this time. I have a feeling it’s my O2 Sensor. It felt like a sport car before and now it feels like it drives like I’m a old nerves lady. Does any one now or get what could be happening?

The O2 sensor is not a likely cause for sluggish performance. I would suspect that the timing belt is off one cog at the camshaft.

+1 for @Rod Knox take it back and have him check the timing belt.

Agreed, this sounds like a timing issue.

What brand of plugs did he use? Honda’s like Denso plugs. Other brands can cause issues. Seen that a lot.

Changing the timing belt and water pump is a pretty big job on transverse engine like this. On my Corolla with the same configuration it involves loosening several transmission mounts and disconnecting the front motor mount and jacking up the engine. Not that big of a deal if everything goes as planned, but sometimes not everything goes as planned. Absent anything obvious from a quick visual inspection, verifying the timing belt was put back on with the correct alignment as suggested above is the first place to start. On some engines – and I imagine this probably applies to yours – the timing belt is routed over 2 camshafts and the crankshaft, and that configuration is particularly easy to get the timing belt alignment incorrect.

If it is not that, likely some sensor or another got damaged or disconnected. It’s also possible a sensor ground wire got disconnected to make room for the engine mount disconnection, and then the mechanic forgot to put it back. The first thing to do for sensor problems is to ask the shop to read out the diagnostic trouble codes. Maybe the engine computer already knows what is wrong.

It would also make sense to verify all the fluid levels are ok, especially the coolant and engine oil. And monitor the coolant temp and oil pressure gauges frequently until this is resolved. Best of luck.

Twenty five years old…How many miles on this car? If the timing checks out, have the shop perform a compression test…

I don’t think it’s the o2 senser anymore. Its hard for me to believe the timing belt wasnt put on right because he is a really good mechanic. Ill talk to him about it though. It feels like something is plugging the fuel or its not burning right or I might just need to do a oil flush and change. Its a little different everytime I drive it. Sometimes at first it will accelerate like normal then after a another stop it will be really bad again. I takes like 7-10 sec to go to 50km/h. It should be like 3 seconds. If its my timing belt I hope it will be ok to fix. Its very weird acceleration in my only problem with the car right now. Its just really slow, and I can feel a tiny bit of shaking when I’m just normally driving which wasn’t there till I went for the new parts.

Just take it back and have them check it over. Since it started after his work he should fix it. The longer you wait, the less likely you are to get it resolved for free. He can scan it and remove the timing cover to double check his work.

It’s usually much easier to correct an incorrect timing belt alignment than to replace the timing belt. There’s no engine mount involvement since a good timing belt is already installed.


Do NOT let anybody talk you into an oil flush . . . that will only flush your wallet of cash

Even a really good mechanic can get a belt off one tooth. He should not have a problem checking. The next thing to check would be the sparkplugs. I do not agree that it is a brand issue, but if the wrong plug, that is the threaded portion is not the correct length, it would interfere with the spark propagation. You have to make sure the plugs are for the Si model and not just a regular Civic, especially not a CX version of the Civic. Possibly the parts man confused CRX with CX.