Morning!

I love my vert. lots of miles and she runs great. Something has me perplexed though.

Lately, at idle, the exhaust smell is kinda strong. I thought no big deal because these cars smell anyway, but when I'm driving at highway speed with top down or windows open, the exhaust smell is really strong and swirls back into my car and fumes me out.

If I close the windows and the top is up, i have no smell at all. There is no visible smoke or anything and my car runs/idles perfect, but this invisible exhaust is rough. I even get 25mpg most of the time.

I have replaced a ton of things in my car over the last year but nothing has straightened this out yet. I recently thought ACV valve or air pump, but those are related to the idle, not highway speeds. Then I thought o2 sensor, but that's not a highway speed item either.

There is no gas smell and no smoke. just an invisible exhaust smell that makes a guy queasy after a while.

You guys have any ideas on what I should look at next?

PZ

 

ok you need to check these things

1. is it rotary?

2. did you leave your windows down/top down?

3. are your cats bad?

4. do you have any exhaust leaks?


if you answered yes to any of these then what you are experiencing is perfectly normal. welcome to the rotary world

 

lol. I'm not a rookie big fella.

1. yes it's a rotary.

2. With my top down, the windows can be up or down and that fume still finds it way.

3. regard to my cats, i figured if they were bad, I would be smelling a rotten egg smell more than exhaust fumes. Maybe not? Otherwise, how would i test out cats?

4. I thought exhaust leak at first, but not a single bit of that smell makes it into my car if i'm top up with the windows up.

 

if cats are bad or airpump is missing and the cats are so old that the catalyst is no longer present, of course you are going to get gnarly fumes. the back of any car is a low pressure area so things get sucked to that spot.

i would replace cats with high flow unit. hook up corvette electric air pump and enjoy that fresh cow smell that idaho is so well known for.

youre welcome, big fella

 

haha. fresh idaho smell. thats hilarious.

My air pump is still present, but with 300k miles on it and the cats too, i suspect, with your input, my cats are causing the stink. I have an air pump in my truck too as a replacement, but i havent put it on it - mainly because I wanted to find out more information about this before i went around swapping parts.

so - i dare ask - are cats going to cost me a pile of cash? Hell, i'd get used ones i dont care.

 

So I will look around and see about getting a new cat on my car. Hopefully that will help the smell. I will see about my air pump too - don't want to have a bad one attached to a good cat.

 

Wait.

Do I need precats or just cats?

 

my 88 gxl is the same
I have a RB true dual setup and everytime I put the windows down, exhaust fumes will come inside the cabin when going 15mph+, worse on the highway.
have the windows up and little to no smell at all.

I am guessing the fumes recirculate through the rear of the car from the aero dynamics of the car or something. I have no exhaust leak.

 

Just get a good HI Flo Cat...Or get a Nice size one for a V8.and make sure it has a split air tube on it so you can hook up your pipe for the 6 port actuators.
Oh..Number 3 on your list,,the "only" time that exhaust smells like rotten eggs is when your Coolant seals are shot.That smell is Burnt coolant.

 

Given your description of the car's performance, it's hard to imagine that the cat is bad.
A failing converter would affect performance, exhaust smell would be the least of your worries.

Assuming all the hardware is good, the next thing to explore is the aerodynamics...it's certainly possible you're just getting "suck-back" into the cabin.
Turn down exhaust tips, a spoiler, diffusers...there are lots of ways to change the airflow and see what effect it has on the problem.

 

I'm going to look into an exhaust leak. I was near it on a non-windy day and at the back of the car, it doesnt smell strong at all, but up front, its alot stronger. Which would make sense why it's so bad near the occupants.

 

hi there.

this is solved finally. i did have an exhaust leak but whats more?

it was my cruise control cable. it is old and not as flexible as it used to be. it was sticking and holding the throttle open. i didnt know it, so i was adjusting the idle and such according to that. therefore my mixture was all messed up becasue my butterfly valve in the TB was held open to the wrong place. i was moving that set screw on top of it all the way down, so the air was barely getting in and the fule was the same - hence the rich-ness.

loosened that cable, got it stable, readjusted my idle and it's perfect now. smooth 850rpm and a little smell, like when i had my other (less miles) rx7 years ago.

whew.

so the lesson here is, if you are having trouble, check out that cruise control cable.

 

285k on the original engine?

 

yes sir.