1999 cobra blow really bad smoke an smells like rotten eggs..

[tborg]

Ok I’m new to this site.. Hopefully someone has a idea. So I ordered a custom tune from VMP performance. I installed the tune car was running pretty good. Then all the sudden it was running like crap.. an now it
Blows out some pretty smelly smoke it smells like rotten eggs.. so I installed my old tune.. Car still runs like complete ass.. I don’t know where to start. Here are my mods Vortech supercharger v2 about 6 pounds probably less then that,90mm mass air 42 pound injecters.. O yea I even fouled the plugs so I brought new ones the miss is gone but still runs like ass.. thx guys for any help.

 

[gt347mustang]

Cats? If yes, that's probably the rotten egg smell.

 

[smashedheadcat]

Check for air leaks between the Maf and intake. Sound like a coupling came loose.

 

[tborg]

Yes it has cats. Never been a issues before. Started acting
Like
This after my first data log

 

[MrMax]

Sounds like your Cat's are gone. How long has it been boosted?

 

[tborg]

I just bought the car in September the car ran perfectly fine until I installed a new tune from Vmp performance after I did my first data log pullIt’s start really smoking at idle and throughout the RPMs. Even found the spark plugs. My white van readings are all over the place.

 

[MG0h3]

Likely cats. Especially if you have low power. Would be more noticeable under WOT


Sent from my iPhone using svtperformance.com

 

[tborg]

A bad cat would make it smoke it’s smokes all the time an car runs very bad

 

[tborg]

All these problems started after my fist data log on new tune. Could the pcm be messed up? Because it’s running pretty rich also

 

[MrMax]

Is it throwing any codes?
I would guess maybe the Cats were on the downward spiral for awhile if the prior tune was not on point. Higher HP boosted applications are tough on Cats regardless. Not much point in doing any more data logging for now. I would double check and review your tune with VMP and have a qualified shop diagnose the issue. If it is the Cats you can replace them, or do a Cat delete in some manner or another. Depending where you live(inspections, etc...) you will either have to trick the ECM with anti-foulers or resistor's on the O2 sensors or simply have the tuner turn them off(most wont do this anymore)
You will need to revise the tune with VMP if you go "free flowing exhaust". Then data log and have them fine tune further.

 

[CobraBob]

Have you noticed any reduction in fuel mileage? Loss of power? Any rattling sounds from the cat area? Might be helpful to read this info from my website. It's specific to '03-'04 Cobras, but can also apply to your '99 Cobra.

By the way, a rich fuel mixture can damage the cats.

 

[tborg]

I think I messed up when I loaded my new tune. I can’t find my stock tune an it runs the same with what ever tune I put at it. Now if I lost the stick tune will ford have to reprogram the ecu or can my tuner send me a stock tune??

 

[tborg]

I’ve had zero problems with this car until the vmp tune an now it runs like ass no matter what I do..

 

[tborg]

An no it isn’t throwing any codes witch is werid because it blows out so much smoke an it does run good

 

[tborg]

OK just pulled the plugs driver side rear spark plug or it goes into the piston whole is covered in oil should I do a compression test and if so what numbers in my looking for thanks guys

 

[gt347mustang]

Oof, sounds like you may have hurt a piston.

 

[tborg]

Well did a compression test on that one cylinder first time it read 90 psi second time it reads 60 PSI so I take it the bottom and needs to be rebuilt crazy only 5 pounds of boost going to call vmp performance on Monday.. the car ran fine before I loaded there tune. Does anyone know anyone who can rebuilt the bottom end I’m in the sac area around Roseville? Thx guy

 

[Chancey]

Well did a compression test on that one cylinder first time it read 90 psi second time it reads 60 PSI so I take it the bottom and needs to be rebuilt crazy only 5 pounds of boost going to call vmp performance on Monday.. the car ran fine before I loaded there tune. Does anyone know anyone who can rebuilt the bottom end I’m in the sac area around Roseville? Thx guy

I doubt the tune alone did that much damage so quickly. My guess is that you were close to failure anyway, and the new tune/power took it on out.

 

[tborg]

Yea any suggestions what I should do when it comes to fixing this thing obviously I’m going to have to rebuild the bottom and correct?

 

[Chancey]

Yep. Find a competant, reputable builder.