Nacho

Hi all, i've searched the threads and did not find a solution to this exact issue, apologies before hand if there is one I've missed.

I have a 1999 GMC Suburban (nick named Big Blue ;-). It's been having this issue for several years now, but getting worse. Whenever it rains if the truck sits for 10-12 hours (like overnight) it will have a hard time starting, I mean I have to crank the starter continuously for about 5 minutes and nothing, then slowly it will begin to try to turn over and if you keep at it eventually it will start to turn over enough that you can give it gas and get it going. I thought I had it solved with recent sensor replacement i've done, where it rained and started with no issues, but this week we are getting rain all week and after two days of rain, the problem returned this morning. Here's what I've done in attempts to correct it.

1999 GMC Suburban with 265,000 miles

I use only OEM parts unless they are not available.
New fuel filter (10,000 miles ago now)
New Cap and roter (less than 10,000 miles now) OEM
New spark plugs/iridium ac/delco (less than 10,000 miles now)
New spark plug wires (about 30,000 miles ago) OEM ac/delco's
Brand new air charge sensor (last week) OEM
Brand new temperature sensor (last week, the one that sits on the front of the engine under the thermostat housing) OEM
Brand new thermostat OEM
Brand new map sensor OEM
Brand new radiator cap (AC/Delco professional)
The starter is new, about 1 month old. The old one was original and after dealing with this issue for a few years it died last month. Third party starter from auto zone (duralast, could not wait for OEM)
New battery (the old one was 5 years old and with all the cranking and charging down, I decided to start fresh) Sears Die Hard Platinum
Fresh antifreeze when I changed some of the above (no leaks) Green not dexcool, it got changed over years ago at some shop and been running green since.
She had a new spider injector put in last year (about 25,000 miles ago) That was not part of this troubleshooting, but one of the injectors failed and engine started to misfire so out she went.
I read that these distributors have vent holes that have screens and get plugged up over time and cause this issue, so as many have recommended on the web, I drilled out the screens to make sure there is a clear passage for air.

Once she stars she runs like a new truck and will start no problem and first key turn for about up to 10 hours siting time when raining. No rain, she stars even if sitting for days. After changing the recent temp and other sensors last week it rained and she sat for 14 hours and started right up, but after two days of rain, and sitting for about 12 hours, i'm back to the same issue this morning.

I also periodically add gas line fuel treatment generally lucas or marvel mystery oil

No check engine light and none recently. I had a check engine light last year, one of the oxygen sensors which I replaced and cleared up the light.

No oil leaks

I did notice when I pulled the cap and rotor to drill out the vent holes that the caps contacts were a bit corroded with white powder so I cleaned them up a bit. I suspect if I put in a new cap/rotor the problem will go away for a bit, but it's less than 10,000 miles old. Maybe with the vent holes and the rest it's more heavily worn and I should have started fresh? Not sure, but didn't look too bad really. Rotor showed some blacking on the tip, but looks about normal.

Maybe the distributor is just too tired?

Any thoughts/recommendations would be appreciated. Thank you all!

Brent Jones

Well, if it wasn't rain related I'd say it sounds like a fuel pressure regulator/fuel spider going bad. But I cant see how rain would affect either. And, they usually don't improve after it starts back up. It will still run with a miss type symptom. Fuel pump can also start to fail and cause that difficult to start with the turning over for a minute or more. I had all three fail at the same time with none of them completely failing just fading over time. After replacing all three as well as the upper and lower intake gaskets, runs like a champ. Wonder if you could possibly be getting rainwater in the fuel system somewhere, Dunno?

Nacho

Thx, but I really think it has to do with the distributor at this point. It definitely feels like a fuel issue, but again once running, no problem and the fuel filter and spider are relatively new. The fuel pressure was checked prior to the spider being replaced and the shop said it was fine. I ran her last night at 10 and then started her up at 7 this morning no problem. I swear if i'd let it go just a few hours longer I would have had the issue because it's wet out. I can battle it in this way, run it late at night and start it early in the morning. That's how I get around it. However, if I forget and don't run it at night and sleep in and it rains, It's done for.

I forgot to mention, one time, a few weeks ago, just before drilling out the vent holes on the distributor, I read that someone put a blow dryer to the distributor to get one started. After cranking for several minutes, I put a heat gone to the distributor for two minutes moving it around like a blow dryer and when I tried to start it, it started right up. I tried that a second time, after very little cranking and it did not have the same affect. Not sure if that was a coincidence or if the first time I had tried for so long that the heat gun gave it the extra push it needed. Either way it's why I went through and decided to drill out the vent holes, but again, I still have the issue. I read yesterday that one guy found one of the wires to the distributor had a green ball of oxidation on it and cleaning that contact solved the issue, but I'm not sure what wire he's talking about, I didn't think there were many to the distributor, crank sensor maybe, but I'd imaging that would cause more issues if that sensor was bad. Still I'll have to get back in there and look around. Any other ideas are welcome.

kevinkpk

Take the cap off when you have this problem, and spray with WD-40. Sounds like moisture issue