Sulfer smell @ idle

1992 4.0l auto, np231,

-new catback exhaust 1.5 years ago
-full tune up end of last summer
-18-19mpgs usually
-tons of power
-no codes
-CCV system cleaned out and refreshed in OCT 2011
-New O2 sensor 1.5 years ago- looked like the original one..haha. Was replaced in response to a code being thrown.


Basically, other than a bit of sporadic, infrequent rough idle (that is usually solved by cleaning my IAC valve once a year), this rig is a solid performer, but every so often, I get a strong whiff of sulfer @ a light, or like today, in a drive-through while picking up some tasty local mexican food.

Probably was excentuated by the fact that I was idling next to a CMU wall while in line for a few minutes.

(To be clear, this is not the rotten eggs smell that you get from a mid-nineties/early 2000's asian car with a clogged cat, nor is it the rich, unburnt fuel smell (love that smell!) that you get from old carbed classics as they cruise down the highway.)

What are the main causes of this? Could it simply be, with no other obvious symptoms, due to the type of gas I buy? I always go to the same ARCO station as I come into town. (we live in the sticks)

Your cat could be going out. I know you changed it 1.5 years ago but what kind did you get?

Sounds to me more like burning wire/switch insulation in the dash, at the AC blower fan switch, or ignition switch or head lights switch which are common causes, as is oil from the valve cover burning on the Ex-manifold.

I don't have an oil leak. fixed it last year. New felpro cork gasket solved that. Plus burning oil doesn't smell like sulfer. ...It smells like burning oil.

Also, I've smelled electrical short/burning smells before. I don't have that issue.

This is a marked smell coming from the outside of the vehicle, intermittantly while @ idle. Cannot be detected with a smellometer (my nose ) while underway.

kdailey4315 said:

Your cat could be going out. I know you changed it 1.5 years ago but what kind did you get?

Click to expand...

Not sure. I don't want to rule out a clogged cat, so I wonder, are there any other common symptoms OTHER than a rotten egg/sulfer type smell?

thanks!