Hello everyone I am new here and need some help with some problems that I have. So as the title says I have a 02 civic ex coupe automatic d17a2 vtec completely stock. So I bought this car for a very very cheap price a few weeks ago I replaced the TDC sensor and cleaned the camshaft position sensor. Car runs great, turns on without a problem, very healthy engine. The engine currently has 190k. Okay so my problem is that when I idle the car at a high rpm, maybe around 4-5k smoke comes out of the exhaust it's like white/blueish... The car does NOT overheat so I don't think it's the head gasket and I don't think it would be the pistons. The car doesn't make no weird noises. I was thinking that I might be the fuel injectors? Anyone had this problem before? Also I get only one code p0420 which would be the cat. converter right? I've never had a cat fail on me so is thier a way to tell if it's actually the cat and not a 02 sensor? I've asked around for a price and they go for 4-500 for a aftermarket new and installed. But then again cat doesn't make weird noises or affect the way the car runs (or at least I think it doesn't). Mechanics are telling me the car has two cats??? I've took a quick glance and only see the bottom one where else would be the other one?

Thanks to everyone

 

The car has one catalytic converter, one resonator, and one muffler.

If you have white smoke, you're burning coolant. If you have blue smoke, you're burning oil. My guess would be either your piston rings are not sealing well, or your valves aren't seating properly.

 

Would a bad cat converter cause it to smoke? I'm gonna replace the cat on Friday. Also let's say it would continue to smoke would it affect California emissions smog check? I forgot to mention that I did add fuel injector cleaner but I think it should have gone away after two weeks.

 

You would need a new catalytic converter if it is failing, in California. Their laws are so strict, that its really unavoidable unless you want fines or your car towed.

 

Alright, okay but what I find strange is that if it were the piston rings or valves that aren't sitting properly the car would burn oil correct? When I bought the car maybe like a month ago I immediately changed spark plugs, motor oil, and motor oil filter. The spark plugs were kinda 'blackish and burnt' from the bottom like if they weren't changed in years (pervious owner was a female). Engine needed a motor oil change ASAP. And as of right now I've checked the motor oil and it's in the spot where is supposed to be (above the second hole) and I haven't added oil since. I've probably put 1k miles already. This car is daily driven. But as of right now I'm thinking of replacing the thermostat, maybe replace the fuel filter and check the fuel injectors.

 

You shouldn't need to touch the fuel filter or injectors. The filter is in the fuel tank attached to the pump, and isn't a wear item.

 

Well apparently it was the cat converter, I just went to get a new one installed and now when I idle no smoke comes out. The guy that installed the cat had told me that the cat that it had was probably illegal because it had no 'numbers' on the cat to identify it. Anyway I appreciate your help thanks a lot.