Exhaust Smell very bad

Hi folks,
I own a 2015 V6 taco, very nice truck.
I have a problem with the exhaust smell... smells like uncombustioned fuel getting out from the exhaust.
Truck idles smoothly, hang an AEM wideband sensor, 14.7 afr with very little oscillation.
Flow tested the injectors in the bench, they are pretty well in terms of flow and leaks.
Spark plugs are good all the six, tried also each coil, and borrow my friend's coils, no difference at all.
Oil consumption isnt noticeable.
Engine has some mods, long tube headers (no cats).
I wouldnt expect that gas exhaust smells like roses, but mainly, every gasoline car i had, didnt have this problem.
Any ideas or any other test to perform?
Pd: last week took out the plastic intake manifold, found the aluminium manifold with some residues of fuel (pinkish color) i think is wierd that fuel is there, considering that inyectors are after this part of the manifold.

Thanks in advance

 

@Torspd @Lucario Runner

 

Using any coolant?

 

Hi bro, using the factory coolant. Car has 20k miles, no signs of coolant consumption

 

You have no cats. Problem solved.

 

I just noticed that you are using a Haltech Elite 2500.

If you have your engine idling smoothly at 14.7, then is this when the exhaust smells bad, or during cold start?

 

Wanted to say just that.... but fangered i was missing something as it seemed too easy.

Drive thru and long waits with long tubes almost makes me cry if theres no wind

 

Don't idle in tunnels.

 

Mine smells too. No cats. It’s a good smell, IMHO.

 

It's the smell of American Feeedom and Horsepowa!

 

Both of the times, but i can say the smell is a little higher during cold start.
So the smell is the carbon monoxide?

Regards

 

Carbon monoxide is odorless. You're smelling the unburned fuel the the cats would normally combust. I'm no expert in these matters, but it seems to me that you can expect unburned fuel when you remove the cats.

 

CO has no smell.

 

As the others said, you are smelling unburned fuel that would be burned off by the cats in an OE system. Yes, stronger smell when cold is going to be normal. I get the same thing with my long tube headers. Slight smell on a nice warm day, burn your eyes on a cold one.

 

Do you actually have a Haltech Elite running your engine? I am quite curious of this. Did you tune it, or have a shop tune it?

 

Yes its a Elite 2500, shop tuned, as said, idles good, the throttle response is also good as well as the power.
Have haltechs in other cars using the same type of fuel and with no problems.
Tried also leaning the afrs to 15.3 smell was slightly worse.
Maybe injectors flow hitting the walls and fuel entering the combustion chamber in drops instead of atomized?
Hans

 

Cold starts should be worse, as the mixture might be more rich. What is your base fuel pressure set to?

It is normal to have that fuel in the exhaust smell, with no cats, so not a big deal to worry about.

 

Fuel is set to 45 psi, ill search for high flow cats or is there anything else i can do to lower the smell?
Hans

 

Drive faster.
In all seriousness- I had gone catless on my '04 STi, and my gf's '16 BMW 435i. The smell you just get used to, and it really is only noticeable when not moving. The power gains we got from deleting the cats and tuning far outweighed the smell.

 

When I went with LT headers with the factory y-pipe, there was some additional exhaust fumes that I could smell when just idling. It was livable in my opinion. When I took it another step further and upgraded to a URD off-road y-pipe, the exhaust fumes was ridiculous. At stop lights, other cars would roll up their windows. I ran the setup like for for about 2-3wks before I decided to add a single Magnaflow hi-flow cat on the y-pipe. This helped eliminate 95% of the exhaust odor.

LT headers with the o/r y-pipe provide a great power gain. Adding a cat took a little HP off the table, but it's worth it to not have to deal with the exhaust fumes.