Well my car is fixed.

Dunno how. Dunno why. But it works now.

Jim, I think whatever you were f'ing with under the hood - fixed the problem.

Thanks!

Woot!

So my car isn't really fixed. It was just messing with me.

Same problem as before, just more intermittent. It seems to happen more when I have more gas in the car.

Weird.

I know the audio on this vid sucks since it's computer voice, but watch this video and take notes. It may expose the root cause of your problem. Especially the part about a wet charcoal canister and the fuel level causing problems.

Evap explained

I couldn't really watch that.

Care to summarize it for me?

Could a wet charcoal canister to be blame?

The fumes from the tank go into the charcoal canister and the intake so as not to ruin the environment. If you have a valve on the canister that got soaked it may not properly channel the fumes in the right way. The other issue is that with a charcoal canister full of water there's no place for the fuel vapor to go when you fill the tank up and the system becomes over pressurized.

My suggestion is to remove the canister and dump out the water and dry out the filter. Then check all the lines for leaks and reassemble. You may want to also check any solenoids you have in the system to make sure they're working right. It would suck to pull water from the canister into the fuel tank or intake.

don't you work for a mechanic ??

I'd inspect all the ignition wires.

I've got a 94 Caprice wagon,LT1, I crunched my hood two days ago in the rain,and the rain has not stopped 'till today. Car won't start...I'm thinking this Water in the Canister is my problem as the hood is funneling water right on top of that spot. It turns over endlessly and coughs. Any other possibilities while i,m here? Thanx.. scott I need it Sunday to pick up another hood.

All things related now have me thinking.
May be a stretch but lets get some answers here.
I came to post up if anyone remembers
if the gas tank should whooosh when you remove the cap or not ?
I remember a ISSF thread that some did & some didnt.
This ties together because of Fishas problem (fixed?) & my recent fuel pump
I go to start the car & it wont. Low fuel outside all day in the heat.
I put gas in it & it wasnt better. Fuel pressure was like 30 & stumbled (dropped)
I siphoned out 5 of the 7 gallons ( I remember the whoosh when I uncapped it) & it was all better.
OK if the canister isnt working right. Clogged or Wet I'm assuming the pressure happens. Because I dont think the tank should whoosh (vapors to the air)
Add the reported bad internal tank wiring that happens & fuel level may have an affect
I know intermittent means no real answer so I may be making this up
At least maybe we can get an answer about the canister

My car still does the - whoosh -.

My problem still rears its head once or twice a week. I can get through it with a few cycles of heavy acceleration.

The tank should make the hissing/rushing water sound as the cap is removed. It means that the tank was under pressure and the cap being removed is releasing the pressure. If the sound isn't present then the pressure is not being maintained which relates to a leak somewhere in the system. Most likely the gas cap is worn out or there's a leak in the fuel vapor line going from the tank to the filler neck as that line never gets replaced by most people.

The evap canister is easy to check. Just unbolt it from the fender and unhook the wires/hoses. Then remove the lid and look inside. It should be empty of fluid and the bottom of the canister should have a dry filter element in it. Don't be suprised if it smells of fuel since that's the point of the canister.

If there is actual fuel in the canister it means the system is overfull and is overflowing fuel directly into the canister. I've never seen this event on an FI car but I have seen it on older cars when the evap systems first started showing up.

If the canister has water in it or the filter is soaked with water then the canister ingested water from outside and is putting that water vapor into the engine anytime the solenoid tells it to purge into the intake. This would cause the same symptoms as a car running on bad gas as the engine sees this event the same as if the car had watered down gas in the tank.

I'm not an expert at any of this but these are the issues I have seen personally in dealing with evap systems.

bammax wrote:

I'm not an expert at any of this but these are the issues I have seen personally in dealing with evap systems.

I'm no expert either so take this as discussion....

bammax wrote:

The tank should make the hissing/rushing water sound as the cap is removed. It means that the tank was under pressure and the cap being removed is releasing the pressure. If the sound isn't present then the pressure is not being maintained which relates to a leak somewhere in the system. Most likely the gas cap is worn out or there's a leak in the fuel vapor line going from the tank to the filler neck as that line never gets replaced by most people. .

Wouldnt this scenario defeat the PURPOSE of vapor control (vapor whooshing to air)?
The purge valve vents fuel vapors FROM the tank TO the intake (& burns them)
I gave Fisha my guess, maybe he'll test it out & give us feedback

The purge valve only works after a certain pressure is reached. The system needs to maintain a set pressure for the fuel injection to work right, which is why a fualty gas cap can cause issues. If you ever run an old style vented cap on a modern car you should see the issues it causes. This is the reason obd2 cars have codes for fualty caps and for fualty evap systems.

My only issue is I'm not sure on his '93 just how integral the evap is to the car since I don't have a chiltons or service manual for that setup. I know on the old carb setups you can pull the entire evap out without a single issue other than some fuel smell when the tank is full. On a '96 you need to do reprogramming to even think about messing with the evap. Any car in between has some built in codes but it varies as to how many and how important they are.

Either way water in the canister is a very bad thing to any setup.

OK that makes sense. Glad you knew enough to convince me.
So if he disconnects the intake connection temporarily (assuming he hasnt addressed the canister)
he should rule out that as the culprit? The 93 uses the same purge valve as 94-96

It's hard to know how well it would improve things since the car is designed to feed the vapors into the intake. I know when I replaced my blown evap lines my car idled smoother and my fuel mileage seemed to pick up a little. I'm always assumed this is because the engine is tuned to adjust for the additional air and fuel being added to the mixture, although this is based entirerly on the idea that the evap purges into the tb at a point that's after all of the sensors which monitor incoming air. The best person to ask would be someone with experience with the tuning tables because they could tell exactly what the pcm/ecm is looking for and expecting from the evap system. I'd still say the best way to check out the system is to look in the canister. It's in the front passenger side fender on the '95-'96's. The '93 should still be in a front fender but maybe not the same exact spot.