I don't know if this will work, but I used to work at a G.E. Appliance store. And if someone had a dishwasher that had a bad smell build up in their dishwasher, we were told to tell them to take a frozen can of orange juice concentrate that you find in the frozen section of your grocery store. And with the washer empty, run a whole load cycle with the can of frozen orange juice concentrate (just the contents, not the can) in the dishwasher. It was supposed to have taken the odors out. Now I have another tip as far as washing clothes with oil in them, and petrol is oil based. I have done this and it works!!! Take one can of Coca-Cola and add to your load with your detergent, and it will take out the grease and oil. You might just do an empty load of just coke, detergent, and water to get the build up out. It even got out old oil stains in my jeans. There is a lot of tips to use with coca-cola. We keep a 2-liter in the laundry room.