: gas pressure in gas tank



omikhail
04-01-09, 10:56 PM
I am getting this issue and I appreciate your help on the topic.

I have a 95 Fleetwood Brougham.
After driving for a couple of hours on the highway and usually if the tank is less than half empty, i start feeling a counter pressure whenever i press on the gas combined with strong hesitations. To the point that if i am slowing down near the exit, the car can and do caugh and stop.
It is like the fuel pump is not working. However, When i stop to fill up, here is what happens.
When i open the gas tank knob cover, you can hear strong pressured gas leaving the tank.
Then i fill it up and the problem of hesitation goes away and all is fine.

Help! what should be done to fix this problem?

Aslo, how can i pull the computer codes from the 95 Fleetwood Brougham?
I used to pull them on my previous 89 Fleetwood, and it was like the Devilles. This one is different.

Thanks for your help.
Michael

thefleetwoodguy
04-02-09, 02:11 AM
you can access the code through the hvac controls, info is in this link
http://myweb.accessus.net/~090/dtcobd1.html

these cars have some issues with the fuel pump wires, melting and making poor connections,
also you might try replacing the fuel filter , since its an easy one to do, and could cause your issues
having the pressure in the tank is not unusaul, my 94 will build up as well, mostly on 1/4 tank or less, follow the instructions and see if you pull up any codes, then let us know

cadillac_al
04-02-09, 08:14 AM
Do you thing the tank is releasing air or inhaling air. I think the tank is building vacuum inside due to a clogged or pinched vent line.

akimball442
04-02-09, 10:41 PM
Do you thing the tank is releasing air or inhaling air. I think the tank is building vacuum inside due to a clogged or pinched vent line.


Absolutely. Check the charcoal canister. Not sure where it is on a 94, is it still under the hood? They have a filter that can sometimes be changed, but see that it has not got a constant vacuum on it. The canister control is supposed to do a purge on the can once in a while, and then shut off. If it's got a clog somewhere and is drawing a vacuum on your tank constantly, that isn't a very good thing.

This can actually collapse a fuel tank under severe circumstances.

Once you find and repair the issue though, it's good to know that your fuel system is that air tight- actually....

It's not legal to use a vented fuel cap on a 1994 car, but it would not hurt to leave it loose or absent as a 'test' to see if the problem goes away once the vacuum on the tank is released.

omikhail
04-03-09, 01:09 AM
It is releasing air when i open the fuel cap.

Lazarus_Rooney
04-07-09, 04:06 PM
im having the same exact problem, and today i drive to school with my gas cap off and the car felt a bit more lively under acceleration. my dad says that some gas caps vent themselvs.... is this true? looking at it i dont think so.

my car is a 1990 brougham.... can any one point me towards where the charcoal filter is? until then ill just keep my gas cap off.

akimball442
04-08-09, 01:22 PM
1990 has a 307 with a carburetor, right? That should definitely not be holding that much of a vacuum. I know for sure on the 307 that the charcoal canister has a filter, I'd look at changing it.

The gas cap is not vented. I think they stopped doing that in the 70s.