Hi everyone, quick question to see if I'm alone. This has happened twice now, both times after the car has sat at least 12 hours. I'll start the engine, and after about 20 seconds I'll hear a horrible grinding sound coming from the engine bay. It's very quick (maybe less than a second), and the only way I can describe it is it sounds like when you grind a gear. Just wondering if it's normal or something I should get looked at.

 

No, but I get a little hesitation in my EX manual when it's cold, especially right after I shift to 2nd gear and give it light throttle. The RPMs go up and down for a second. Anyone else seen this?

 

A wild guess, but could it be the ABS system initializing? In some cars that can make interesting, but momentary, noises.

 

Granted, "cold" for the summer will be interesting compared to the cold of the winter, but mine feels about the same from the start after sitting for hours. The only thing I noticed when "cold" with my M/T, is when I'm about a block away, I hear a slight noise coming from the bottom of the car. As if something closed or opened.

 

I have never heard any sort of grinding noise.

Are you sure its not an extremely noisy EGR valve? it does occasionally do a self check to make sure there is exhaust flow. Its Hondas way of not having an EGR temp sensor and flow/pressure sensor in the EGR system. The ecu is basically checking for different AFRs before and after valve opening/closing. If it doesnt see a change in AFR, it assumes the EGR valve is dead and throws a code