Hey guys I tried searching but found some conflicting info, I have been having noticing an awful exhaust smell in my car while driving, it only happens during higher rpms like upon merging onto the highway, I'm not engaging VTEC or anything t but when I get around 4000 rpms I can usually start to smell something in the car.

Furthermore my rear bumper is always coated with fine black dust that wipes clean, this is driving me nuts since I've already fixed so many issues with this car. I don't believe it's an exhaust leak because I don't smell anything when idling only at higher rpms, there is an aftermarket header, catalytic converter and tanabe cat back on the car (previous owners)

Mikey (bitanga) eluded to the residue possibly being due to an aftermarket cat, which seems very possible.

Motor was torn down and rebuilt about 10k ago, broke in correctly, before the rebuild it was burning oil like crazy, even at very low rpms, could there be an issue with my cat from the previous oil burning?

I have a magnaflow aftermarket oe replacement cat in the garage I'm thinking about swapping out today, any input would be appreciated, thanks guys!

Mark

Edit: I've also read that the charcoal canister could be the culprit, in trying to diagnose the issue alone so i don't have someone to hit the throttle for me while it's idling or on jacks etc.

 

I had a lil bit of time to investigate and it looks like where the header and cat meet the flange isn't sealing properly, even though it's fully tightened, also the rubber grommet that seals the secondary o2 sensor from the outside was hanging loose, my guess is since the leak is literally right under the o2 sensor hole that exhaust fumes that are leaking is making its way into the cabin via the hole right above it, I think the exhaust is leaking only at higher rpms and is for the most part doing its job but when pressure is increased or starts to leak.

I'm going to disconnect the header and attempt to make a better connection. Keep you guys posted

 

i get exhaust fumes in my car at high rpm as well, still don't know whats causing it.

 

Most likely an exhaust leak.

OP are you burning oil at all?

 

Just confirmed that I am burning some today. Before I had this motor rebuilt I was debating just getting a swap but wanted to keep the original parts together. I should have just swapped in a JDM b18c, I think I'm going to just swap a motor in this winter and leave the original motor for parts.

 

There are a lot of reasons the car will eat up oil. And swapping in a used motor doesnt sound like the best thing to do if you are worried about burning oil. Chances are the used swap will burn oil as well.

Do more troubleshooting, such as a leak down test. If you built the bottom end 10K ago, it might be fine and you might just be losing oil through the valve seals/guides and need some head work. A leak down might help confirm that.

 

Thanks for the advice, I am pretty certain valve seals were done at the same time but I guess a leakdown will show for certain. I'll look into it, I'll let you guys know what happens.