I made a horrible decision after my Ranger got totaled and bought a $800 94 Jetta to save the insurance money from the accident. Anyways I have poured tons of stupid money into it. When I first got it, the car had trouble starting in the rain but eventually she would fire up. If I drove it immediately away after finally starting, it would jerk really bad when I gave it gas while shifting, until 4th gear. Once she ran for a bit it would smooth out. Nowadays if it rains the car won’t start at all, just keeps turning over and I have to wait for a nice dry sunny day then it starts right up. My mechanic worked on it recently and replaced a sensor in the distributor and the crank shaft sensor, because they showed up on the diagnostic as bad. Once his work was complete, he said he sprayed the engine with water and it started. So that was a week ago and it’s raining and it won’t start, the engine just turns over so it’s not a starter issue. The car only has 143,000 but I am gonna get rid of it this fall but I just wanna know what this wet weather problem is. Any suggestions would be most appreciated .
The cause could be one of several in the ignition system but the most common is bad spark plug wires. I would suggest changing them first.
Try replacing the spark plugs (properly gapped of course) and then spraying the entire secondary ignition (coils, wires) down with a liberal coat of WD-40.
Not starting when it is wet is most often ignition problems. Replace the spark plugs is 1st. Then replace the distributor cap and plug wires. That should do it.
If the car has COP’s (coils on plugs) then it won’t have the distributor cap and wires. In that case you replace the plugs and the rubber boots that are inside the coils. The boots can go bad and are then they are susceptiable to moisture. If you replace the coils you can save the coil, but eventually the shorting out will kill the coil too. Each new coil can run about $50.