Knocking Sound Low RPM

Reply Subscribe

Thread Tools

Search this Thread

Nov 11, 2011 | 11:16 PM

89C4RedRed

Thread Starter

Heel & Toe

Joined: Nov 2011

Posts: 24

Likes: 0

Knocking Sound Low RPM

I have this knocking sound, that you only hear between 1000-1300 RPM. My car has 61K Miles. Dunno what it could be as I have just got new rod bearings installed. Any ideas or suggestions would be great.

Nov 12, 2011 | 08:56 AM

sailorsteve

Drifting

Joined: Jun 2010

Posts: 1,853

Likes: 8

From: Westerly RI

If the problem is cylinder-related, you might get a clue by pulling one plug wire at a time with the engine warm and idling, to see if the noise changes. Ignore that the engine will miss and the idle will drop, just listen for the knock each time. If it changes or disappears with a particular plug wire off, that is the suspect cylinder.

Nov 12, 2011 | 10:26 AM

89C4RedRed

Thread Starter

Heel & Toe

Joined: Nov 2011

Posts: 24

Likes: 0

Ok, I pulled each spark plug and listened and each time the knocking would still occur. I lifted the car and went under it and I have found the source of the knocking, Its coming from the Catalytic Converter. Does that mean their bad? Thanks for help.

Nov 12, 2011 | 10:52 AM

sailorsteve

Drifting

Joined: Jun 2010

Posts: 1,853

Likes: 8

From: Westerly RI

Sounds like the internals of the converter are loose. When that happens, you install a new one.

Nov 12, 2011 | 11:12 AM

89C4RedRed

Thread Starter

Heel & Toe

Joined: Nov 2011

Posts: 24

Likes: 0

Ok Thanks. One last thing, can i still drive it without causing any major damage?

Nov 12, 2011 | 04:40 PM

sailorsteve

Drifting

Joined: Jun 2010

Posts: 1,853

Likes: 8

From: Westerly RI

As long as the converter's not plugged, you can drive the car without worrying. A quick test for a plugged converter is to see if the inlet and outlet pipes to it are about the same temperature (be careful, burns are no fun). If the converter is plugged, the inlet pipe will be much hotter.