HFC smell? - hard acceleration
 

I have a burning smell under hard acceleration that smells like oil or some kind of chemical.

It doesn't have the bad fart smell of a burning clutch. Plus, I get the same smell even when I accelerate in one gear without using the clutch.

I just got back from the dealer and they said it was my HFC. But I just can't imagine it would stink up the cabin this much. I notice it with the windows barely cracked and only under hard acceleration (so I am going 60 or 70 mph when the smell enters the cabin). It seems like there is no way for exhaust gasses to go from the rear of the car and into my window at that speed. My service advisor literally just shrugged when I mentioned this lol

The cats have been on the car for about 4k miles so grease and sht from manufacturing has burned off by now.

I'm wondering if there is oil leaking somewhere I can't see and its getting burned off at high engine speeds. I don't see any oil around the pan or dripping on the ground though.

Again, it isn't an awful smell like the clutch but it smells like some kind of burning chemical. Maybe rubberized undercoating getting hot and outgassing? I'm pretty much clueless here. Has anyone had a similar issue?

Edit:
I just went out and tested this again. I took a friend to get another opinion. He noticed that the smell is similar to freshly fired shell casings which actually is close. I haven't added gunpowder to the gas tank (yet :stirthepot:) so what the heck?

You have enough miles that it shouldn't be burnoff BUT a HFC is generally going to have SOME smell to it. More than likely you have an exhaust leak from the install or possibly something burning on the pipe. Check for bags and things of that nature and tighten up every bolt on the exhaust. Also check to make sure you have an even mount on all the flanges... if a hack shop tightened one bolt completely it is possible the flange isn't sitting right.

I'll bet it's a bag sticking to the tailpipe. Good call Matt :tup:

try to close the air vent on the center console. Normally they are open even with the vent off. that might reduce the amount of air comeing in from the cabin from the engine bay also. I also noticed you cant run the heat without leaving the vent open. Otherwise the a/c kicks on and that was how I discovered to keep the vent shroud closed.

If you haven't already, get under the car and make sure all the bolts are tight.

Update:

Thanks for the suggestions guys. I wish there was a bag stuck to the exhaust. That would have been an easy one.

I felt around all the flanges with the engine running and listened with a 2 foot section of hose (shadetree stethoscope) but couldn't find a leak.

I'm going to get someone to hold the exhaust tips closed briefly (with leather gloves on and some rags) to see if that makes a leak more apparent.

I retightened the bolts about 1500 miles ago as a precaution. They're still very tight.

It smells like fired gunpowder mixed with an unpleasantly intense new-car-smell. Sounds crazy I know but thats the best description I've come up with. I'm taking it to another dealer next week but would rather figure it out myself if possible.

Could my clutch be slipping even when accelerating in one gear all the way to redline then back down? It would have to be a defect since I only have 6200 miles on the car. Clutch fluid is 1/3 below the high mark, never raced.

How to check for clutch slip...

Take your car on the highway, no need to speed, in sixth, push in the clutch and get you car up to about 6k RPM, engage the clutch slowly while you push the accellerator down. Get it floored before you fully engage the clutch fully. The RPMs should drop down immediately when the clutch is fully released. Easy to tell if the clutch is starting to go out this way since you can get full torque into it without having too much speed change during the test. Do it quickly, 1/2-1 sec on the clutch engagement cause you don't want to burn it if it's still good. RPMs will come down gently if your clutch is near end of life.

Just curious if you ever figured this out? i know the thread is old...

Just recently i feel like im having the same issue. Car drives fine but notice a smell on hard acceleration.

Just curious..

I still get the smell, but it isn't as bad.

Can you describe the smell? Mine isn't like anything I've encountered on a car before. Its almost like gunpowder.

Usually the rotten egg smell is the cats breaking up inside clogging the exhaust flow and heating up too much? Are the HFC.s brand new?

I am having the same issue but mine is bone stock with less than 3k miles on it. The smell only occurs after hard acceleration. I figured it was the car burning off some factory coating but it is not a smell I have ever had on any other vehicle before.

Mine really just smells like exhaust for the most part. Im taking it to the dealer to get the exhaust tightened up just to be sure...

I have this too, it comes and goes and it only started this summer. Smells like oil that was spilled somewhere burning off. I inspected absolutely everything it could be and found nothing, so I'm assuming it is nothing.

I had this the first day I installed them, under hard acceleration there was this burnt tire kind of smell, but no smell the day after. Just the first couple hours of driving and its gone. :tup::driving:

Have you tried different brands of gas? Maybe there are some additives in the gas that you are using that is causing the smell. I have Berk HFC and CBE and I do get a little exhaust smell, so I need to get underneath to see if any of the bolts have loosened up a bit.

When I got my Santa Fe in 2003, there was a smell that the dealer was caused by certain gasolines. However, it really didn't seem to matter which gas I used.

Mine does this occasionally too. Smells kind of like hot brakes, but I only get it under hard acceleration. When I was researching buying a G before I bought this car I remember an issue where oil was pooling around a rear spark plug. Haven't looked at mine yet. It is really not too bad at this point, and since it really doesn't seem like oil I haven't been real concerned.

Another weird smell issue I have is when the car sits overnight on a cool night, when I start the next morning with the AC on Fresh, within 10 sconds a strong hot plastic sort smell that goes away within another 10 seconds. Won't do it again until it sits overnight on a cold night.

Just last night I noticed a weird smell while driving on the highway. Have had HFCs on over a year with no issues. I thought it was a beater car up ahead spewing off gas or fumes, but once I was in the clear the smell was still there. Smelled kind of like a freshly tarred road; oily gas odor. Around town no strange odors. I haven't been on the highway since to see if it happens again. Hope my HFCs aren't on their way out.

Yes! this is the the same smell this weekend, this wasn't there before HFCs so im guessing this is def the case, as my brakes work just fine and had no such smell under hard braking as well. :driving:

Yea mine does it to , I'm not worried. Kinda smells like a race car

I sometimes get the same "gunpowdery" smell on hard acceleration in my '09 Touring. My theory is that the cats are temporarily overloaded and I am smelling unburned hydrocarbons and products of incomplete combustion (PIC) (eg, CO, incompletely burned gas, &c) that are making it through the cat. I'm assuming that, with a modern, computer-controlled engine, unburned gasoline will be a very minor component, so PIC will be what is making the smell. YMMV.

ive noticed that this is only during really hard acceleration though and I mean full throttle pedal to the medal and a couple pulls. Other than that she doesnt burn or smell. :driving: So for now its good, and I think quite normal.:tup:

Just switch to test pipes and learn to leave your car on recirculate and never, EVER put the windows down, like me, LOL

I'm getting that awful foul smell as well. I notice it within the first 5-10 seconds of starting up my car. Ive come to believe that its my Berk HFC. Its never smelled anything like this before. Ive had my twin turbo kit installed for about 7000km, so Im guessing that the element in the HFCs are burning up from the extra heat.

My solution is that Im just going to completely swap out my Berk/Stillen combo and replace it with 3" GTM down pipes, and the 3" FI exhaust. If it still smells after the swap, then Im going to have to check my tunes because Im running it rich.

I would be willing to bet that that most tunes run rich to be safe....ESPECIALLY when under WOT..... when you add HFCs or test pipes, you are going to smell the unburnt fuel smell. Its not that bad

Just bought a 2010 Nismo with 58k miles. FI HFC and full MXP Exhaust and I have the same issue. It’s like a really strong exhaust fume smell in the cabin. Anyone ever find the solution for this?