'87 Silverado V20 Issue. Fuel pump/rain???

[Nickster 7]

I recently purchased a 1987 Chevy Silverado V20 P/U for use in bad weather to avoid taking my '95 Z28 out when it's bad. For the first month I had it, the truck did great in the snow, and in the rain (even heavy at one time.) Recently I took it to work on a rainy day. It started up and ran with no problems at all and got me the whole way to work. When I went to leave work later, I went to start the truck, and the motor just cranked without even a hiccup. I tried it again about 3 days later (I had to leave it sit as I was going to be out of town the next few days) and it started up and got me home with no issues. I drove it to work the next day (it rained) and even after sitting out in the rain all night, it started up and got me to work. That day I went to leave from work, and it left me sitting again!

I returned the next two days only to find that it wouldn't start again. With the help of some buddies from work, we figured out that the right fuel pump (dual tank) wasn't working, as if something just shorted out in the rain. The truck would run on the left tank, but it would bog down and shut off, so I haven't used it. After some fiddling around with the tank selector switch, which doesn't work well at all, I got it back to the right tank. I decided to try and start it one last time, and wouldn't you know it, the fuel pump came on, and the truck started and ran like normal. Just yesterday, it sat outside in the rain again, and had the same issue. I haven't gotten it started again since, but I'm going to try today.

Does anyone have a clue what the issue might be, and what to check? I'm not extremely handy with vehicles, but any advice would be appreciated. I can give more info on the truck if necessary.

Thanks-Nick

 

[dhamp]

Don't know if it's the same, but mine has always given me issues when it sits or is driven in hard rain since I've had it. Supposedly (according to my old man) it didn't start doing that until he put an aftermarket dizzy cap on it. I went back w/a delco cap last summer, but I haven't left it out in the rain to test that theory. I did clean the motor after the tune-up, and it took about 8 tries and a 15-min drying period before it finally started again. And I deliberately tried to not spray directly onto the cap.

 

[Nickster 7]

Don't know if it's the same, but mine has always given me issues when it sits or is driven in hard rain since I've had it. Supposedly (according to my old man) it didn't start doing that until he put an aftermarket dizzy cap on it. I went back w/a delco cap last summer, but I haven't left it out in the rain to test that theory. I did clean the motor after the tune-up, and it took about 8 tries and a 15-min drying period before it finally started again. And I deliberately tried to not spray directly onto the cap.

I actually Don't think that's the problem, as it runs just fine as long as the fuel pump works.

 

[GTME94]

I'm not sure about the pump problem but to properly use the fuel tank switch you have to hold the switch for 3-5 seconds for the valve to switch from one tank to the other. My valve was sticky so I cycled it back and forth with the ignition switch on run but without the engine running. I could hear it when it started switching properly. I have a carb so I don't have the electric pump in the tank.

 

[Nickster 7]

I'm not sure about the pump problem but to properly use the fuel tank switch you have to hold the switch for 3-5 seconds for the valve to switch from one tank to the other. My valve was sticky so I cycled it back and forth with the ignition switch on run but without the engine running. I could hear it when it started switching properly. I have a carb so I don't have the electric pump in the tank.

My switch is just like a toggle mounted on the dash. I can't really hold it in place as it is kind of like a light switch. It works sometimes, but I think there is some kind of bad connection somewhere. And maybe my pump is just going bad? I got it running today, and it seemed to really bog down more than normal.