V6 vortec 4.3 has a hard time starting on humid rainy days

Doug_Scott · October 7, 2014

that is good to know, I will check the screens when I put the new cap on. Thanks for sharing that

Keep in mind that the screens were put there initially to keep stuff OUT of the distributor. Stuff like spiders. Never checked, but is a spider web conductive?

Brandon87 · October 8, 2014

Keep in mind that the screens were put there initially to keep stuff OUT of the distributor. Stuff like spiders. Never checked, but is a spider web conductive?

Yep, spider man had conductive webs so I'm pretty sure every domestic spider is the same. lol

Brandon87 · October 10, 2014

Today I got my new cap and rotor in the mail and I installed it. It was like $15 on ebay and It seems like a good quality cap, its thick heavy plasic and it has brass terminals. The only problem i had was that the seller sold me the wrong screws for the cap so i ended up using the old screws. The old rotor had dead spiders inside and it was dirty so i cleaned it all up and put it together and it fired right up. The true test will come when i have to do a cold start or a start on a humid day. Thanks for the advice and ill update later.

Noszor · October 12, 2014

Just a heads up, get your battery checked out too, I had similar issues with my accord not to long ago, had issues starting when it was raining, but started fine when it wasn't, never hurts to make sure and cover all your bases

SouthernSilveradoGuy85 · October 12, 2014

The cap and rotor was the problem my 98 5.7 had when it had problems starting after rainy days. So as long as the cap is quality then you'll be fine. A cheaper cap will fix it at first but over time still allow the inside of the distributor to get a little damp so it won't last nearly as long as it should. I went as far as getting an AC Delco cap and rotor to make sure.

Brandon87 · October 20, 2014

UPDATE!!!! Well after replacing the cap and rotor all seemed well until this wet and cold 43 degree morning. This morning it was really hard to start but I got it to start by pumping the gas until it fired up but then i had to keep reving it to keep the RPM up so it wouldnt die. I guess I'll replace the Ignition module and spark plug wires next. what do you all think about it?

SouthernSilveradoGuy85 · October 20, 2014

UPDATE!!!! Well after replacing the cap and rotor all seemed well until this wet and cold 43 degree morning. This morning it was really hard to start but I got it to start by pumping the gas until it fired up but then i had to keep reving it to keep the RPM up so it wouldnt die. I guess I'll replace the Ignition module and spark plug wires next. what do you all think about it?

Well that's exactly how it was when I had that problem with my 98 5.7 and all I did was change the cap and rotor. I would have to hold the gas pedal down until it cranked and then keep holding it until the stumbling went away. What happened was moisture was able to get in the cap and on the contacts of the rotor and distributor. Prior to that I had changed the entire distributor just because it was old and in bad condition. A few months or longer was when I had that same problem that you're having and the cap and rotor I bought was AC Delco to make sure it was good quality. How old is the main distributor? I'm thinking moisture is still getting in there.

Doug_Scott · October 21, 2014

UPDATE!!!! Well after replacing the cap and rotor all seemed well until this wet and cold 43 degree morning. This morning it was really hard to start but I got it to start by pumping the gas until it fired up but then i had to keep reving it to keep the RPM up so it wouldnt die. I guess I'll replace the Ignition module and spark plug wires next. what do you all think about it?

Pumping the gas pedal does nothing on a fuel injected engine. You could have just held the throttle open a bit while trying to start it.

I think you have a truck that does not know it is cold outside. When it is colder, it requires more fuel to start the engine. If you have a scan tool, on next cold morning, check and see what temp the ECM thinks it is outside via the ambient air temp sensor.

Brandon87 · October 21, 2014

Well that's exactly how it was when I had that problem with my 98 5.7 and all I did was change the cap and rotor. I would have to hold the gas pedal down until it cranked and then keep holding it until the stumbling went away. What happened was moisture was able to get in the cap and on the contacts of the rotor and distributor. Prior to that I had changed the entire distributor just because it was old and in bad condition. A few months or longer was when I had that same problem that you're having and the cap and rotor I bought was AC Delco to make sure it was good quality. How old is the main distributor? I'm thinking moisture is still getting in there.

I have only owned this truck for like 2 months so I am unsure how old the distributor is, It still has the original spark plug wires and had very fouled up crusty spark plugs so I kinda am assumeing that who ever owned this truck before me never really did much maintnance at all, so It might be fine to just say that its the original distributor. I dont know how long a distributor can last but my truck has 164 thousand miles.

Brandon87 · October 21, 2014

Pumping the gas pedal does nothing on a fuel injected engine. You could have just held the throttle open a bit while trying to start it.

I think you have a truck that does not know it is cold outside. When it is colder, it requires more fuel to start the engine. If you have a scan tool, on next cold morning, check and see what temp the ECM thinks it is outside via the ambient air temp sensor.

I dont have a scan tool. I will go down to my auto zone and see if maybe they have a scanner in their loan a tool program. I really need t figure this out before the snow starts to come in next month here in indiana.

Kevinreitan · October 21, 2014

Run your VIN through here, I know there is a known issue with the 4.3 in silverados.

https://recalls.gm.com/#/

Brandon87 · October 21, 2014

Run your VIN through here, I know there is a known issue with the 4.3 in silverados.

https://recalls.gm.com/#/

I ran it and there is currently no recalls with my 2002 gmc sonoma

Brandon87 · October 22, 2014

I noticed that this morning it was about 38 degrees and my truck had a hard time starting like usual but this time I cycled the key on and off several times and it started right up with no problems at all. I didn't even have to give it gas. Idk whats going on but someone told me that maybe it was the throttle position sensor. anyone have any imput on that?

Doug_Scott · October 22, 2014

Does your engine have a throttle body that sprays fuel every time the key is turned on? That would imitate a choke if you turned the key on an off a few times before starting the engine.

Silverado4x4 · October 22, 2014

Would also indicate a weak fuel pump or fuel pressure regulator, cycling the key would let the pump run and build pressure before starting. Try this next time turn the key on but don't start leave the key on for about 10 seconds then start, that would point to a weak fuel pump if the truck starts fine and idles.