96 Windstar Exhaust Leak

[tebo77]

I have an exhaust leak I can hear and smell but cannot see. It is in the engine compartment but I don't know if it is the manifold gasket or where the "Y" pipe meets the manifold. Is there anything I can put into the throttle body safely just to make it smoke for awhile to find the leak? I tried a cap of motor oil tonight but no smoke. I was afraid to put more than that in. I tried stuffing a rag on the end of the exhaust pipe but still couldn't see anything.
Also would exhaust leaks cause codes P0171, P0136, P0161, P0401, or P0174? Have all new o2 sensors, DPFE, egr valve, egr valve sensor, clean injectors, clean egr ports, clean MAF, so trying to narrow these down as well!
Thanks so much for any help you can give!

[wiswind]

If you have a exhaust leak in the engine compartment.....you might try finding it by sound.
I would not try making smoke with oil......as that may crud up the catalytic converters.

Is it possible that some fluid has dripped onto a hot exhaust part and caused the smell?

I would also give a look around the EGR tube that goes from the front exhaust manifold to the EGR valve....including those hoses that go to the DPFE....the P0401 would be a EGR flow that the DPFE is reporting a different value than the PCM is expecting.

TAKE NOTE that codes are stored for a while once they are set.
It takes a certain amount of time without a failure for them to clear.....
What this means is that you can correct the problem....but the code will remain for a while.

The other leak points to check would be where the oxygen sensors mount into the exhaust and the flex pipe that connects to the rear of the "Y" pipe......in front of the muffler (the BIG square/rectangle under the passenger compartment).

If the "Y" pipe has not been off.....then I would not expect a exhaust leak where the pipe goes up against the exhaust manifold.....
A good inspection from below with a light might help you determine if the exhaust manifold studs are intact (in case 1 broke).

[tebo77]

I had the "Y" catalytic converters done a couple months ago...you made me remember, wiswind, the car was super quiet right after that and must have steadily gotten louder and I didn't notice right away. The nuts on the back "Y" end had loosened back up when I checked last night. Much quieter now and no smell! Had the codes cleared, I'll see if they come back up. My tech friend with the scanner said the lean codes could be from an exhaust leak, along with the egr code. Thanks for the response!

[Freakzilla69]

Originally Posted by wiswind

TAKE NOTE that codes are stored for a while once they are set.
It takes a certain amount of time without a failure for them to clear.....
What this means is that you can correct the problem....but the code will remain for a while.

What's "a while"? I've got P0171/P0174 codes after rebuilding and I did have a loose connection to one of the exhaust manifolds, I've tightened it up but it still seems a little louder than it should. Could a small exhaust leak cause these codes?

[wiswind]

There needs to be a certain number of "drive cycles" before the codes will clear.
What constitues a drive cycle....I am not sure......
The most common cause of the codes you mention is a vaccum leak.....I have also gotten them from dirty fuel injectors.

I would track down the source of the "noise" and solve it.....as you could be getting nasty fumes (CO) inside the passenger compartment.