Defective ignition coil(s) Bad spark plug(s), spark plug wires, or spark plug boots. Faulty fuel injector(s) Malfunctioning fuel delivery system (fuel pump, fuel pump relay, fuel injectors, or fuel filter) Major engine vacuum leak. EGR valve stuck in the wide open position. Clogged EGR ports.
The following conditions can sometimes cause smelly urine, but they are uncommon: 1  urinary stones â these may cause an ammonia-like odour (read about bladder stones and kidney stones) 2  a bladder fistula â this is an abnormal connection between your intestines and bladder.
See your GP if: 1  You have symptoms of a urinary tract infection (UTI) , such as pain or a burning sensation when urinating and a need to urinate often. 2  This is the most likely cause of unexplained foul-smelling urine. You have symptoms of a urinary tract infection (UTI) , such as pain or a burning sensation when urinating and a need to urinate often. 2  This is the most likely cause of unexplained foul-smelling urine.