Help, my exhaust is killing me.

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matthon

matthon

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The exhaust fumes are making me sick, and it is worse with the windows open.

My car is undrivable due to the fumes, and even letting it idle in the driveway is nauseating- in the house!

I have had my share of cars over the years, and the V8s are no Honda when it comes to exhaust fumes.
I have another car that is a turbo V6 that has 3 inch exhaust- it is not pleasant to sit behind it in a lawn chair, but I never even smell it in the car.

I drive it to the local store and I come home smelling like the pipes run directly into my shirt.

People who drive behind my car comment on the thick smell coming from the exhaust.

I have checked the entire system, the heat riser leaks a little, but everything else has been addressed.

I'm wondering if I should replace the entire exhaust system, but on the other hand it appears it is just a giant carbon monoxide pump and running pipes a few car lengths back wouldn't even help.

It has stock exhaust manifolds, and stock appearing pipes/mufflers, all the way out the back.

Here is what I have done so far:
1) replaced the manifold bolts and studs.
2) new gaskets.
3) new donut gaskets; manifold/pipe union.
4) changed some clamps that were loose.
5) replaced the trunk weatherstrip.
6) rebuilt the carb, and leaned it out as much as possible.

I really can't drive it anymore like this.
 
I can fix it.... Ill take it off of your hands.
And guess what? I will do it free of charge.
You won't even have to pay me to take it
Cuz I am such a nice guy hahaha
Just messing with ya, hope you can figure it out
 
hkeller said:
Try replacing your pcv valve.
Hkeller
Click to expand...
It has a breather on one valve cover, and one of those breathers on the other that has a line to the base of the carb- not a true pcv I guess, but my understanding is it serves the same purpose.
 
I have one of those also, I might get a real pcv mine smells like its running rich all the time
 
what do the plugs look like. somethings amiss. tuned correctly you can run open headers on the street. you need an air fuel ratio reading.what size carb and what size motor? give us something to work with.could be a bad wire and 1 cyl. not firing.
 
daredevil said:
what do the plugs look like. somethings amiss. tuned correctly you can run open headers on the street. you need an air fuel ratio reading.what size carb and what size motor? give us something to work with.could be a bad wire and 1 cyl. not firing.
Click to expand...

I will admit I am not an expert with plugs, and they have not been out recently, but I did change them twice in an effort to eliminate fouled plugs, and out of desperation.
Both times the plugs look good, clean, not black or burnt out.
I'll check the plugs again tomorrow.

383 with a Weiand intake, not a highrise, and a 750 Holley. I rebuilt the Holley last year, and I tried to tune it again today for a few hours with the help of a few friends.
Pulled the screws for the bowls, the fuel is up to that level. The mixture screws are out about a turn and a half, anything less and it will not stay running. I can get away with the rears out only a full turn.

Last year I replaced the ignition with an Accel unit, new coil, new wires.

It has been like this throughout this whole process of replacing this, and getting a new that.

I have a horrible taste in my mouth still from driving it today- this is not good.
 
Sounds to me like you're running way rich, mine was doing that at first with the new carb. She'd drive ya out of the garage with your eyes burning and watering. Plugs showed a little black, went down 2 sizes on the primary jets and much better and now plugs are brown (I like a little rich). Also check to make sure that your secondaries aren't open a tiny bit at idle and therefore bleeding in extra fuel. Have you had to set the primaries idle screws way low to get it to idle down correctly. Also recheck your float levels on the Holley that they aren't to high.

Terry
 
I never changed jets before.
Are they between the fuel bowls and the carb itself?
How many are there?
What size should I get?

I didn't realize this could be the issue, so I want to change them asap- I feel sick.
 
If your holley is a double pumper there are 2 jets front and 2 back.

If it's vacuum secondary, there are only 2 jets in the front with a metering block in the back.

In either case pull the 4 screws off the front bowl and the jets are on the bottom side of the metering block. They will have #'s on them.
 
thats good to know, I thought there was 4 jets in my 750 vac sec
 
I'm going to pull the plugs tomorrow and see what they look like, no time today.
Today I was also told to advance the timing so the 'burn' was hotter, and that the size of the jets should have no bearing on the issue I am having.

More info and opinions are helpful, but it soon leads to confusion.

What everyone agrees on is that it runs very well as is, but I feel it could run better.

I'll follow up tomorrow, hopefully with good news.
 
check the power valve.. i heard if u lower ur idle mixture screws all the way and the car dies ur power valve is fine
 
i am also getting this same issue in my /6. i walked in to work today and it's as if i was just sleeping in a closed tent of exhaust fumes. i stink. i looked underneath and the exhaust pipe only extends about 3 inches off the muffler so that is an easy fix. i'll try that and see if it fixes it but i will be watching this thread for more info. do the same issues that apply for a V8 apply for the /6? i believe everything on my motor is stock but not sure. i'll look into everything tonight. car runs good albeit a bit sluggish when warming up. exhaust smells worse with windows open and when i slow down it gets worse still.
 
Bottom line is almost always to lean that thing out........and be sure the timing is set to handle the lean mixture.

THEN, be sure to check and re-check your FIREWALL........look at every single place where air can get into the cabin.....seal them up, if they are open, even with something as simple as 0000 steel wool around the cable or whatever goes through the hole....see if it makes a difference.

I had a problem like this on my Demon a while back, and it turned out to be a combination of a few things mentioned here. Gaskets, lousy pipe joints, and the firewall, in addition to running too rich.

If you can't lean it out yourself, take it to a local garage who knows what they're doing and have them tweak that carb before you get more sick. 8)
 
Update: I did not have time to pull any plugs, but it gets interesting anyway.
A friend of mine took a look at it this morning, he was the one who wanted to advance the timing.

On the way to his shop, I put a few gallons in, (no gas gauge), but this time I selected the highest octane. I know I have before, but not regularly.
He checked the timing but made no changes, and he adjusted the carb.

And no more sickening smell!

I am still in disbelief. I even made him drive it for 20 minutes, and took it for a ride myself for another 20.

Was it his adjustment on the carb? Possibly. It was already lean, but he did some adjusting and set the idle a little higher. He suggested I drive it like that for a few days and then he would set it again, at a lower idle. He also agreed that I should replace the 750 with a 650.

Was it the higher octane? Probably?

We put it on the lift and I noticed one of the mufflers must have experienced a backfire at some point. It was not leaking, but the baffles inside are probably messed up, which may not help.

Also, could it be possible that a rich mixture combined with bad manifold to pipe gaskets affected the mufflers and exhaust, maybe filling them up?
It must be the first time in a while that the all of the exhaust gasses are actually making it all the way through.

I'm still not convinced it is solved, its difficult to really tell right now, I need to leave it be for a few days and see if I smell it again.
 
Im glad to hear its better. Hopefully its fixed
 
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