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.
Foods that Cause Stinky Urine. Some of the causes of stinky urine are harmless. Eating certain foods can make your urine smell bad or different. Asparagus and coffee are two well-known offenders. Many other foods, drinks and spices cause foul smelling urine, but this smell is normal.