Anytime i downshift to slow down coming onto an exit ramp, etc i get a strong burning odor. it doesnt smell like clutch, it's hard to describe. It smells like something is getting hot and burning. Does hard decel make the crossover, etc extra hot maybe?

 

whats the girl look like in your passenger seat?

you might wanna ask her too get checked

 

Downshifting to slow down in a turbo doesn't work so well... I suggest brakes...

and methinks yer doin it wrong.

 

I also just found my 02 sensor wire melted to the downpipe

 

Oh, well, that's not good. I'd suggest replacing that and getting the wire away from the exhaust. that could be a good source of your issue... but I'd be willing to bet that it's not only while downshifting.

 

I had a similar problem, after changing to stand-alone EMS:
Downshifting I got a really strong, sharp smell in the car, bringing tears to my eyes.

In my case it was the car running way rich when the load was low, and the RPM came slowly down after downshifting. Lots of CO.

Also the engine choked, when accelerating after downshifting, and threw out black smoke in the exhaust.

Problem , once identified, was in my case easily solved by changing a few cells in the EMS.

 

Thats also a possibility. It's definately rich, the whole back area by the exhaust is covered in soot.

 

The other possible issue is that you are getting max vacuum under decelleration - if you have bad valve guides, piston rings or even a failing bake booster the engine will suck in more fluids during high vacuum.

 

I downshift every day to slow down. I don't just throw it in the next gear and drop the clutch. I rev match as best I can (and I'm fairly good at it now). No problems to date (been doing it for 4 years).

 

you did my valve guides a few months ago, so we know thats fine

 

Mine had that too. Solved now. Do you have a WB with logging capabilities?

 

I still have this problem, I havent noticed it or driven the car much in the past few months but i just fixed a decent size vacuum leak and now it's back worst than ever. It's not just when i downshift, it's also when driving off boost in low gears.