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Discussion Starter #1
Hi all,
Had this problem for a while now, but finally getting tired of it.


For starters:

300 I6
EFI 4.9 dual exhaust manifolds.
2.5" exhaust out the back.
Catalytic converter (about 5 years old)
Dynomax turbo muffler
465cfm 4bbl Holley carburetor
DUI Performance Distributors ignition (with plugs gapped to 0.055")
Passes local emissions



When I'm driving, it's fine, but when I really get on it, like WOT up to peak RPM, and then back off, it just smells STRONG of engine. It's like this odd mix of too lean/too rich, oil burning, sulfur, etc. etc everything. It just stinks.

I have a wideband O2 sensor on it, and the AFR is really healthy. 12.5:1 at WOT, 13 - 14:1 at part throttle, 14 - 15:1 at cruise. It's really nicely spot on. My last fillup was 14mpg with casual around town driving.

Everything seems really healthy, runs really well, etc. I'm just tired of the smell. I had my brother drive it for the first time yesterday and he didn't want to get on it because he said the smell made his eyes burn.

I'd just attributed to "old truck engine" and no smog or EGR, but then we went for a spin in his '69 Camaro, which has NO emissions, and after really getting on it and flooring it around, there was nothing.


Any ideas? Kinda tired of it.
 

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313 Posts
sounds like catalytic converter, or could be burning a fair amount of coolant, are your coolant levels good?
 

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Missing any cats in your neighborhood?

I would:

powerwash the motor, trans and underside - then drive and look for leaks

no EGR right? Any chance a breather hose, valve cover to carb is cracked and under WOT is leaking?
 

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Discussion Starter #5
It's not losing coolant and as stated it does have a cat that's only 5 years old. That doesn't mean it isn't bad though. Maybe I'll have a shop check it out and see.

The engine does have a little bit of blowby. Do you think that's what I could be smelling when I floor it? It's this odd acrid burned oil smell. Very sharp.

Other than that, it has all new gaskets.

No EGR, open element air filter and crank case breather:




Pretty simple setup.
 

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is it just me or does your brake master cylinder look wet? That could easily give you a reason for a stink, why you'd only smell it at full throttle would probably just be air pressure shoving it (the smell) into the interior.
I don't see anything that would explain why you are smelling oil. My mustang used to have a breather that POURED oil mist out of it when it got hot and I never smelled oil driving it.
 

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Discussion Starter #7
The master cylinder leaking is a pretty recent thing (at least I think so).
The cap just isn't sealing well enough so it leaks when I brake hard.
Who knows though. I guess I'll see after I get that remedied.
 
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