# Someone,somewhere has to know the answer to this **URL:** \ **Category:** General Discussion\ **Tags:** gmc, 1500\ **Created:** [October 18, 2009, 2:36am UTC](https://community.cartalk.com/t/someone-somewhere-has-to-know-the-answer-to-this/38263 "2009-10-18T02:36:09Z")\ **Posts on this page:** 7\ **Page:** 1
**Author:** ![govenator](https://avatars.discourse-cdn.com/v4/letter/g/0ea827/32.png) [@govenator](https://community.cartalk.com/u/govenator)\ **Post date:** [October 18, 2009, 2:36am UTC](https://community.cartalk.com/t/someone-somewhere-has-to-know-the-answer-to-this/38263/1 "2009-10-18T02:36:09Z")
my 1998 GMC sierra p/u will not start when the weather changes to cold and/or damp.I have replaced many sensors,the computer,the fuel pump etc,etc.I can spray it with a fire hose and it will fire right up…but a little dew and its curtains ! help… ---
**Author:** ![UncleTurbo](https://avatars.discourse-cdn.com/v4/letter/u/e9a140/32.png) [@UncleTurbo](https://community.cartalk.com/u/UncleTurbo)\ **Post date:** [October 18, 2009, 2:44am UTC](https://community.cartalk.com/t/someone-somewhere-has-to-know-the-answer-to-this/38263/2 "2009-10-18T02:44:38Z")
The parts you mentioned replacing are not moisture sensitive items. Moisture sensitive items are spark plugs, plug wires, distributor cap, rotor, etc. How long since any of these parts were replaced? If any of these ignition parts has a bit of dust on them this dirt holds the moisture and leads to more problems. ---
**Author:** ![waterboy](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/waterboy/32/764_2.png) [@waterboy](https://community.cartalk.com/u/waterboy)\ **Post date:** [October 18, 2009, 3:20am UTC](https://community.cartalk.com/t/someone-somewhere-has-to-know-the-answer-to-this/38263/3 "2009-10-18T03:20:59Z")
Distributor cap and rotor guess 1. Might as well do some new plug wires also ---
**Author:** ![govenator](https://avatars.discourse-cdn.com/v4/letter/g/0ea827/32.png) [@govenator](https://community.cartalk.com/u/govenator)\ **Post date:** [October 18, 2009, 8:15am UTC](https://community.cartalk.com/t/someone-somewhere-has-to-know-the-answer-to-this/38263/4 "2009-10-18T08:15:07Z")
thanks everyone for answering…plugs,wires,rotor are new…dist. cap looked great so i didnt replace it…i guess i should…but why doesnt washing it or spraying it with hose cause any problems…it makes me think it has something to do with cchange in barometric pressure and temperature ---
**Author:** ![kmccune](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/kmccune/32/1237_2.png) [@kmccune](https://community.cartalk.com/u/kmccune)\ **Post date:** [October 18, 2009, 12:27pm UTC](https://community.cartalk.com/t/someone-somewhere-has-to-know-the-answer-to-this/38263/5 "2009-10-18T12:27:39Z")
Its called the dewpoint,when things cool below the dewpoint, moisture condenses internally and suddenly electricity has another path of least resistance-Kevin ---
**Author:** ![UncleTurbo](https://avatars.discourse-cdn.com/v4/letter/u/e9a140/32.png) [@UncleTurbo](https://community.cartalk.com/u/UncleTurbo)\ **Post date:** [October 18, 2009, 12:32pm UTC](https://community.cartalk.com/t/someone-somewhere-has-to-know-the-answer-to-this/38263/6 "2009-10-18T12:32:15Z")
Distributor cap can look “great” but have tiny cracks that change the tracking of the electrical current. Sometimes you can see these carbon tracks inside the cap. It’s not a big expense, replace it. The quality of spark plug wires varies widely. Some new wires are lousy and easily affected by moisture. If you bought “cheapie” wires at Walmart or Pep Boys then the quality is suspect. Hosing down the motor and moisture from condensation are different. Condensation moisture can get into places (like under the dist. cap) where hose water can’t penetrate. On a very dark night let your eyes adjust to the low light and run the motor in the dark and watch for sparking and arching. Perhaps you’ll see the problem. Routing of the wires can make a difference in some motors. ---
**Author:** ![govenator](https://avatars.discourse-cdn.com/v4/letter/g/0ea827/32.png) [@govenator](https://community.cartalk.com/u/govenator)\ **Post date:** [October 18, 2009, 3:03pm UTC](https://community.cartalk.com/t/someone-somewhere-has-to-know-the-answer-to-this/38263/7 "2009-10-18T15:03:54Z")
dewpoint…now we`re onto something…thanks…gonna start with new dist. cap…will keep u posted tho dont know when weather will change again…nice now could be like this for weeks…sunny socal lol