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.
Some vitamins and sulphur-containing medications also result in stinking urine. Dehydration causes concentrated urine, therefore the smell is strong as well. This can also be a symptom of some diseases. To be sure, have a urinalysis. Most of the time, bad urine odor is a sign of some kind of UTI. Fruity urine odor is indicative of diabetes.