What should you do i drive a 2000 vw jetta and it wont start should i check the relay first or the pump?

Answer 1

It depends on what you mean by "it won't start." Some additional questions/answers will help narrow down the problem. Does the starter crank the engine? Is it out of gas? (I had a vehicle whose fuel sensor failed in the FULL position, so we drove it until it ran out of gas but the gauge said it was full. I didn't realize it until we dropped the gas tank and it was extremely light-weight.) Is the fuel pump bad? (This can be checked by removing the fuel line at the engine, feeding the line into a container to catch the gas, and cranking for a brief instant; if fuel comes out, the pump is probably OK.) Various sensors, if bad, will also prevent starting. One notorious sensor for causing this problem on VW's is the crank position sensor. Typically when this sensor is going bad, the engine will stall soon after reaching normal operating temperature, or you will be unable to re-start the engine if the engine is still hot; for example, you take a trip to the store, and you come back out and it won't start. Let the engine cool down, and it starts promptly. If this is the case, try replacing that sensor.