Underhood Odor After E85 Switch
 

I thought I'd ask the larger group here if anybody has noticed the same thing and if what I'm smelling is normal for a car on E85 or potentially an issue.

To preface, I realize that the exhaust gases will smell a little differently when burning E85 and have a little sweeter smell thanks to the ethanol content. This is not that at all. I tuned my car this past Sunday so it hasn't even been running E85 for a week yet, but two days ago (Wednesday) on my drive home, I noticed a smell coming through the air conditioning, reminiscent of urine, but not as strong.

I dismissed it as environmental, got home and parked the car in the garage. It's hot here and a hot, damp (rainy day) car in the garage caused the garage to reek of that same urine smell. I opened the garage door to let it air out and figured I'd keep my eye on it. Yesterday afternoon it was dry and I didn't notice the smell through the AC on the way home. When I parked in the garage, I popped the hood and sniffed around. The strongest smelling area was near the front of the engine bay, around the resonator off the airbox. The smell wasn't obvious upon opening the hood - I literally had to sniff around to notice it.

Getting in the car this morning, the garage had the odor back, but it wasn't as strong as Wednesday evening. It's wet here today (again) and driving normally I didn't notice the smell again until I stopped at a light. AC started piping it back in again, likely because no air movement/flow.

My header and overpipe are coated by Jet Hot, which protects I think up to 1300 degrees, so unless the E85 exhaust gases are that much hotter (I thought they were supposed to be cooler), I doubt it's that coating. The only other thought is maybe fuel system? I know E85 isn't good for the lines, but it has only been five days.

Anybody else have this smell, or does anybody have any thoughts as to what it could be?

Cats?
Seriously I noticed mine spraying my exhaust the other day after running E85..

LOL - I don't have any cats of the feline variety and only a HFC in the front pipe of the automotive variety.

It's definitely coming from under the hood, only noticeable when driving the car when stopped as you smell it through the air conditioning.

clutch smell? slightly fishy?


I think burning coolant smells slightly sweet.

What about cats of the exhaust variety? You could have an exhaust leak ahead of your front or mid pipe cats. You can get some pretty funky smells from uncatted exhaust.

My interior began smelling sort of musty as a result of the ac lines being clogged and condensation dripping onto passenger floor mat.

Not fishy at all - just ammonia-ish like urine. I've smelled burning coolant before and it doesn't smell like that either, unless they put a new variety in our cars. I checked that level last night when I was poking around under the hood and it was completely full.

This could be a possibility, but would just be weird that it seems the most pronounced at the front of the engine bay (near the nose). Think I do have a pinhole leak in the OP to FP junction, so maybe I'll start with fixing that with a thick Grimmspeed gasket.

I suppose that could be a possibility too, though I don't have any wetness anywhere in the interior - how did you clean it out?

It would not take much of a hole to get an odour.

If you can smell exhaust fumes under bonnet you almost certianly have an exhaust leak, also check the 02 sensors are screwed in all the way so ring is tight. after coating you will likely need to retapp 02 sensor bungs its M18 by 1.5 mm pitch tap\chaser

Could be the coating itself if it's fresh. I've heard of a lot of weird smells from that stuff

The only thing i can think of that smells vaguely urine like under a hood is coolant. Check for leaks?

This is really the only thing that makes sense. I'll get it up on a lift this coming weekend and try and see if I can figure out if I have a leak. That said, this smell is significantly different than what's coming out the tailpipe. However, if the leak is where I think it might be, it'd be pre-cat.

The coated header and OP are about a year old now. I'm just wondering if something is getting warmer now than it used to, so it's starting to release an odor when it's warm.

I thought the same thing - but the coolant reservoir shows completely full and the coolant itself looks great.

Pre cat can smell really bad! It is what we used to smell all the time from all cars actually.

Did this ever get figured out? Last week mine started doing the same thing. only when a/c is on and only for the first couple of min. I checked cabin air filter and I have catted exhaust.