blueta

Well it happened again this morning. One thing that is consistant with last time is it rained. I didn't think it rained the first time it happened, but if I think back it did. I just didn't drive it for a couple days after it rained. That's where it gets weird. So everytime it happened it rained at night. Come morning it ran like crap for a little. So you would say something is getting wet and causing the problem. Thing is I can drive it in a downpour (like I did last night) and have no problems whatsoever. I can let it sit for a couple hours and it's still fine. It's only after it rains and I let it sit for 8+ hours that it'll act up. AND even if it stops raining it'll do the same thing for about 3-4 days after. That doesn't make any sense to me AT ALL!

Mikey851

Just curious; how did you do the airbox mod? Did you get the filter in there and leave the bottom cover off or is your filter exposed?

chevysalesman614

how about: take it to the dealer since its under warranty...

blueta

I did, but since it didn't act up during the time there and no dtc's I got a clean bill of health. And I removed the whole thing for the airbox mod. But since I can drive it all day in the rain with no problems, let it sit then problems, they go away after it's warm, and let it sit again DRY for the next couple days and it'll still act up ONLY when first started after a longgg period, I wouldn't lean too far into that. But I guess you never know. BTW, I've had federwell cai's in my gtp, air filter right off the ground with no box on a supercharged lt1 and various others and never had that happen. Who knows I guess lol. I'm also not sure if it's a rain problem yet or it's coincidence. I'll know more if it happens again with no rain.

Mikey851

Yeah, I don't necessarily expect that the airbox mod is your problem I was just curious. Maf sensors can be really finicky, so just keep an eye on it. One other test you could do is a fuel pressure test. Just hook up a gauge at the fuel rail and turn the key on; check if you have 50 to 60 psi and that it doesn't drop fuel pressure too quickly. A leaky injector can cause the problems you speak of; but then again there are many other possibilities as well.

blueta

Actually that was on my mind. I wasn't sure if these returnless systems held pressure after they were sitting for a while (hours) like the return style. My fuel pressure gauge broke so I never got to trying it. Guess I'll borrow one. Thanks for the reminder

bluecobaltss06

The fuel pump runs when you cycle to the key to the "on" position. Also if there is no leak in the fuel system it should hold pressure for ever. If there was a leak you would have an extended crank after the car sat for a while.

SCcobaltSS

iTrader: (2)

Take it to the dealer and tell them to leave it over night. Go up there with them and start it, see if it does it.
Backfire usually means that its getting a lot of gas right? So it has enough gas.
What does the exhaust smell like?
Rain cant affect these cars if they're just sitting because there is no distributor to get wet nor can water get where the intake is if its just sitting.
Cracked injectors? (I think someone said) Then it doesnt happen when it warms up because heat make things expand, it might of closed up. But if it doesnt do it all the time when its cold, that might or might not be the injectors.
Lol. All of this sounds contridicting but just keep giving us an update when it happens. When, what, where. And aybe we can figure something out.

blueta

I still didn't borrow the fuel gauge. I'll get it this week. I also want to see if it rains again and it does it. That way I'll know that it has something to do with it. But rain CAN in fact effect any car. You can have a cracked coil and the moisture can get in it. Chaffed wire can wick water down inside causing all kinds of problems down the line (why you never buy a flood car even if it's running fine at the time), wet maf etc. I'm 95% positive it has to do with water, but the way it goes away and comes back after it sits for a long time baffles me. Next time it does it (hopefully the rain) I'm going to take it to the dealer with all the info I came up with (yeah, like they listen to anyone anyway haha), and tell them to take it through the carwash there and let it sit till the next morning. In fact I think I'll take through a wash in the next couple days and see if that sets it off, besides I only washed it once since I've owned it

EDIT: BTW, it hasn't backfired again since the last time but it did get the bogs and smoke which smell a LOT like gas. But that doesn't mean it's ness. a fuel problem since it can be caused by running rich OR missfiring spark (unburnt fuel). I can't wait to get hpt and look at my open loop settings!

SCcobaltSS

iTrader: (2)

If it was misfiring the computer will know and you'll have CEL, which you dont. If your MAF sensor got wet you'd have to be standing in 24" of water and it can take a little bit of water before it craps out. Moisture in the coil? I dont think that would be enough to make it run like that, IMO.
Have you checked all your positive wires? One of my other vehicles did that randomly and I found a loose wire getting burned by the exhaust.
Im just throwing stuff out there trying to spark someones memory on this subject.

blueta

Well not a saturated MAF, but it can get moisture. If I sunk deep enough to get the maf underwater I would be having some other issues A cracked coil would probably set a missfire code if I think about it (moisture causing coil spark to ground out on whatever is close). Wires all seem to be fine, but of course I didn't go through the whole harness and check every mm of it. Just checked the parts that could chaff or burn. Thanks for the ideas though! Every idea is a new lead to something.

djcasper_bpm

i find that any car will run like **** when its -30 outside.. but yes i have that problem in the winter. just let it warm up to 100, thats when the heat kicks in anyway. no problem after that.

blueta

Yeah that's true, but we're talking in the middle of summer here.