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 foods and medications, such as asparagus or certain vitamins, can cause a noticeable urine odor, even in low concentrations. Sometimes, unusual urine odor indicates a medical condition or disease, such as: Bladder infection. Cystitis (bladder inflammation) Dehydration.