Hello all: I have a 1999 Blazer 4 door 4X4 and when it rains I can't get it to start. I have replaced the distributor, wires, spark plugs ( it needed it anyway), crank sensor. cam sensor, check the fuel pump and pressure. I check the electrical aspect and all was good. I even tried a different ignition control module but still no start. Is there anything else I need to check? The truck sits outdoors due to I live in an apartment. What else would cause the truck to not start after it rains? The truck does crank over fine and the starter was replaced a few months back. Any ideas or helpful advice would be greatly appreciated.

Thank for your time and help.

 

* Moved to '2nd Gen Tech' *

 

What do you mean that you checked the electrical aspect and all is good?

When it won't start, check and see if you have 1" of strong blue spark at the end of a spark plug wire (spark plug end).

George

 

Wet air filter? 🤔

Is it showing any codes?

 

In my experience, wet weather often exaggerates ignition system (spark) issues. This is diagnosed most easily by using a spray bottle of water to mist over the engine while it is running at night or in a dark place. The water mist will show you if you have any spark leak from the various ignition system components (wires, cap, coil/icm). Even though you have replaced most all of these components, I would still recommend this diagnostic step to rule out an issue with those new parts.

The next thing I would check is the drains in the bottom of the distributor itself. You can do this by removing the cap, rotor, and cam position sensor, then blowing compressed air through the drain hole. If I remember correctly, the factory distributor has a screen in the drain that can get gunked up and actually hold moisture/humidity.