exhaust smells like sulfur

[ezrob]

My x was running just fine. Then one day it just start running bad sputtering, exhaust smelling like sulfur and poor fuel economy. Any suggestions?

 

[KPT]

Is your CEL on? Could be bad O2 sensors.

 

[james t]

more than likely you have a bad converter. how many miles on the truck?

 

[jimbo74]

Originally posted by james t
more than likely you have a bad converter. how many miles on the truck?

as soon as iread your post, i though bad cat, then jamest asked... so we are thinking alike.....

 

[Alec]

Yup, sulfur smell and drastic reduction of economy and performance is usually due to a bad cat.

 

[ezrob]

it has 83,575 miles, thanks for the help

 

[Glacier991]

From an earlier thread on the exact same subject (I HIGHLY recommend you do a search, you will be amazed how many issues recur!)

The following explanation is not mine, but out of my archives - on the WHY of the rotten egg smell:

"The sulphur smell from the exhaust, is actually caused by running the engine/cat convertor slightly lean for long periods and then running under a rich condition (ie going up a hill under heavy load) This is when the sulphur smell (rotten egg) is produced.

Under relatively lean conditions, the sulphur found in gasoline is converted to sulphur trioxide, then during the rich running condition the sulfur trioxide is converted into hydrogen sulphide (rotten egg smell) within the catalytic converter."

So, you can try different brands of gas, or check and see if your Forward O2 sensor is lazy. If you are not getting a MIL (CEL) light, it's probably only lazy (e.g not switching fast enough.) Maybe you can find a shop with a O2 sensor tester. Before OBDII, that was the easiest way to see what they were doing. There is one for sale on the used and for sale section here. I'm guessing gas and maybe the lazy front O2 sensor.


Happy Exploring

Chris

 

[ezrob]

thanks Chris, I will try to find a shop with a tester.

 

[Glacier991]

Rob your 96 will output sensor info as data stream to any OBD-II scanner (NOT CODE READER< BUT SCANNER!) Should be easy to check.

Chris

 

[ezrob]

It wasn't the cat or the O2S. I cleaned the IAC, MAF, replace the plugs, wires and the PCV. I will replace the fuel filter this weekend. But the X runs like a champ. I think the cat was having a problem with the unburned gas.

 

[Glacier991]

Good job! Way too many perfectly good cats get replaced needlessly.

Happy Exploring

Chris

 

[SWLathrop]

Classic example of a faulty DPFE module. If the problem crops up again, I'd look towards that. I know that Ford extended the warranty on these. Not sure which year they started with, but my 97 was one of them. Had the same problem with my 01 Sport and just replace the one on my 01 Stang for the same thing. Spits, sputters, runs like crap, no fuel milage and sulfur smell. My daughters 02 Stang is doing the same thing. Pulled the DPFE and it's full of water from the exhaust. Makes them crap out. CEL only came on the Sport.

 

[joehawk]

I believe the major cause of cat failure is running a rich mixture [which is what gives the sulphur smell]. If your sulphur smell is still present IMO you are running a rich mixture, and the rich unburned fuel will burn in your cat causing it to overheat and melt down. I would run the OBD 2 scan check. Some states give you a free check through DEQ to see how your vehicle is running, and any fault codes would show up[DEQ in Oregon won't pass your vehicle if any fault codes show up]. You would know if there are any fault codes present, if not the actual code. And if not trying to register the car, here it is free, I believe. Some auto part stores will hook up for free as well. I would be concerned that it will cost alot more in the near future replacing the cat if the problem is not fully resolved related to the sulphur smell.

 

[ezrob]

The odor went away after replacing the plugs and wires.