Hey guys,

I just bought my 4th S4 NA. I am having a problem with it: The car has a lack of power. THe compression is good (mid 80's 3 bounces both rotors) Also, it failed emmisions. (High numbers at idle and at mid rpm's.) The exhaust was just replaced from the motor back (including addition of a new cat). I changed the spark plugs, air filter, and fuel filter.

Anybody have any ideas?

THe car does not stall or sputter or surge or anything else, it just lacks power and failed the emmisions.

THanks,

Rob

 

80's isn't very good for compression FYI.

 

yeah 80's is in the "prepare you rebuild" zone. I think high 90's and up would be considerd good

 

Assuming that is a real compression number. Piston testers are less then accurate in this case and if the test was done incorrectly (ie. throttle not held open, cold engine, slightly flooded) then numbers will be low.

If you are running rich, you need to do the full 60K tuneup as specified in the manual. If that doesn't solve it, test/replace the water thermo sensor and have your injectors professionally cleaned by an injection shop.

 

You mentioned the addition of a new cat. Is the airpump hooked up to the new one and pumping air to it?

If you have done a 60k tuneup and have air pumping to the cat you shouldn't really have any problem with emmisions. If you do then there maybe something else wrong.

 

As far as power goes, you said you had a new exhaust put in. Can you verify that your auxilary ports are opening? Do you have the air pickup thingie attached to the cat?

 

yes, the air pipe is attached and the ports are opening. I will check to see what is involved in the 60K tune up.

Thanks,

Rob