Possible moisture in fuel tank issue? UPDATE: Now with video!

[Pocket Chant]

Alright, so first of all, I derped. I happened to leave my gas cap open throughout the rain that was supposed to be snow. I left the cap on the door, and the door shut, so I didn't notice it was open for a while. I fixed it and it was fine. Later, though, I was driving and lost power from the engine. It seemed like it wasn't getting enough fuel, and I had to keep it at 3k+ or it would nearly stall out, occasionally backfiring. It'd last for a little while, then clear up and be perfectly fine.

This was three days ago. Yesterday and today though, when I first started the car, it ran fine without any problems. After I drove it, then parked for a bit, the problem would resurface. I think it's moisture in the gas tank, but I'm not sure. Should I just put Heet in it or could it be something else?

EDIT: Here's a video of the situation. This seems to only happen after I've started it up before.



And a link, since embedding is iffy.

[dnguyen1963]

Put Heet in the gas tank. Water is heavier than gasoline and sinks down to the bottom of the tank where the pump inlet is located. You must have a shit-load of water in your tank. If Heet does not help then draining and drying (stick a hose with compressed air for about 20 min) the tank would be an option then re-fill with fresh gas.

[akonsing]

i think you should heat it a bit. it will evaporate what ever is causing the problem.

[dnguyen1963]

Heat and gas vapor is not a good combination. Highly recommend against doing this.

[Pocket Chant]

Yeah, no. Not doing this. Video added to the main post.

[jlevie]

That is not moisture in the fuel supply, but rather some sort of engine management problem. The first action would be a smoke test.

[Pocket Chant]

Well that's slightly relieving, I think...

What I'm not sure is portrayed accurately in the video is that it'll bog completely regardless of how open the throttle is, and I have to pump the throttle to get the revs moving again. I'm going to check all my connections and see how that goes.

[jlevie]

I found that apparent in the video, which is one of the reasons I said it was an engine management problem.

[Pocket Chant]

So, pulled the battery for a bit, seemed to fix about 90% of the issue. No more bogging or stalling, but the engine is running a bit rough still. I may try it again, because I let the car idle instead of driving it immediately after
Sent from my PG86100 using Tapatalk 2

[Pocket Chant]

So it eventually ran smooth, whatever. It was fine until I ran it through a car wash (touchless), when the problem resurfaced. I played around with the battery cables and it went away, so I think it might be an issue with corrosion? The terminals look fine, but I couldn't get the negative cable off the battery at all. I'm going to have a look at it when I have some free time, but that won't be for a few days. I'll update with what I find.

[Pocket Chant]

So, problem came back. I'm pretty stumped, too, this time not even pulling the battery worked. I still have good voltage and all, could it be a fuel issue?

[dnguyen1963]

If the problem resurfaced afte you have gone through a car wash then I would concentrate on electrical problems. Go through the car carefully and examine all grounds.

[jclar]

If the problem resurfaced afte you have gone through a car wash then I would concentrate on electrical problems. Go through the car carefully and examine all grounds.

This. And I wouldn't rule out intake leaks at this point too, as mentioned earlier. Check your grounds, and clean them up if you haven't already done so.

[Pocket Chant]

Uhh.

So I finally had time to check the condition of the grounds during lunch and... well, I couldn't find it.

I did find this random eyelet though, is this where the ground cable should be?



If I don't have a ground, I'm not sure what to do, as this was a recent occurance. I ordered new cables though, so they'll be delt with anyway.

[dnguyen1963]

Bentley manual shows all the ground points.

Table t. Wiring Harness Ground locations
Ground point Location

G1 00 In luggage compartment, behind battery (6-cylinder models
with trunk-mounted battery)
In engine compartment on right shock tower (all models with engine compartment-mounted battery)

G1 02 On top rear of engine (4-cyl inder engine only)

G1 03 On right front shock tower (2.5i engine only)
On left side of engine block, above starter
(2.7e engine only)

G1 04 On front fender, behind left headlights

G200 Beneath instrument panel, above brake pedal

G201 On steering col umn, near horn brush/sl ip ring

G300 Beneath left side of rear seat bottom

G301 In luggage compartment

G600 In windshield header