JLCustomizing

I changed my carb out and put a new fuel pump on along with a visible fuel filter. My car kept basically hitting a brick wall at 45mph at 3/4 throttle or 35 at WOT. I popped the hood to see what was going on and noticed it would empty out my fuel filter. What would cause this?
1984 Trans AM
Has a chevy 350
Mechancial fuel pump, mechanical carb, and disty

ex-x-fire

Is the fuel filter infront or behind the pump?

JLCustomizing

In front before it hits the pump

ex-x-fire

Its supposed to be after the pump near the carb. Fuel pumps dont draw gas as good as they push it, I'd make sure the feed line is unrestricted. Remove the gas cap & blow air through the line in the direction towards the tank.

JLCustomizing

Well I took the fuel line off behind the pump that had the filter on it and gas was pouring out decently. I put a new line on without the fuel filter now it wont idle for more then 8-10 seconds before it kills off. With the fuel filter on it would idle for about 5 minutes before it tried to kill off.

Spectrabullet

I am in that same position right now. I thought it might be an old fuel line by the rear axle that seemed a little soft. I pulled the line off and it drained like crazy, it was pouring out. I replalced the line and took it for a ride and it died basically when the fuel line emptied out. The fuel filter was bone dry. I got under the car and wigglled that newly replaced line around and it filled the line back up with fuel and it made it home and died in the driveway when the line ran out of fuel. I had the gas cap off the whole time. I thought maybe a bad cap or something. The interesting thing is the line when opened drained heavily and when reconnected the fuel pump cannot draw it up until the car is off then somehow gets siphoned out of the tank and down the line to the pump. There is a hangup somewhere. Did you happen to figure out what is causing the issue with your car?

JLCustomizing

I took the line off that had the filter on it and replace it with a solid line then tuned my carb up a little bit and got it going fine. My gas guage was off to so I was probably almost completely out of gas as well.

Brando5641

iTrader: (-1)

lol



You need to have a filter AFTER THE PUMP not before. If it still wont run go buy a new pump they are like $12.

Spectrabullet

I have a clear fuel filter after the pump. I just replaced the fuel pump thinking this was the problem. The car has an issue of running the line out of fuel and not getting more going through it like a badly vented fuel tank. When I disconnected the rubber fuel line at the rear of the car it flowed like a faucet but when it's connected again it runs out of fuel shortly after driving the car. You can put it into neutral and fire it back up once the line gets filled with fuel. Then it runs out again. I am stumped. I am not sure if the pump is bad and it is just returning the fuel to the tank rather than pumping it to the filter and into the carb.

Brando5641

iTrader: (-1)

Try leaving the gas cap off.

Spectrabullet

I tried that but had no luck. I uncovered one other piece about this yesterday. I bought 5 gallons of fuel and tried to put it in the car. I got about 2 gallons in and it will not take anymore, it splashes out and will not allow any in there. I can shake the car and here it sloshing around in there. I let it sit for a few and added more but could only get a small amount in there. I have read a few articles and forum posts and it sounds to me like there is a ventilation issue. I know there is a one way vent valve coming off the tank attached to a hose that bolts up to the rear axle and also there is a vent tube that runs into the charcoal canister. So right now, if I have to put a wager on it I would say that canister may be the problem.

Spectrabullet

OK here's the deal. I finally figured this stupid thing out. Check valve that is parked pre-charcoal canister. This thing is clogged and plugged. As soon as I removed it the fuel that was trapped in it started gurgling. This tube is suppose to be a vent for the fuel tank not a fuel reserve. The fuel had been backing up to the tank and not making it's way up the fuel line to carb and crapping out on me. I had the check valve off and waited until it seemed as though it was done venting and added fuel like normal. It took all I had no back up this time. I put the gas in and the car ran and drove like normal. Prior to this if you would have asked me what the charcoal canister did I wouldn't have the answer. It is a piece of knowledge that I feel takes up valuable space for something more important now.

Eleanor62

Is the fuel filter infront or behind the pump?

Brando5641

iTrader: (-1)

If you would read a little you would see this question has already been asked

Spectrabullet

In front of the pump. I don't think I have ever had a filter behind the pump on anything I have ever owned.

Spectrabullet

One more time on this one. Well maybe. If anyone cares..... The car ran great that day and then. Well the next day was a different story. This thing was pissed. It didn't want to do anything. I couldn't get any fuel to go up into that clear fuel filter. I tried all kinds of things to make sure there were no plugs anywhere on a send or the return lines. I could get air to blow into the tank and air to the front of the car. I am stumped. I continue to mess with it. I took the fuel pump off and it seemed like it was performing as it should. I decided I will make the investment into an electric inline fuel pump. I hooked it up and the filter still wouldn't fill with fuel. For some reason neither of the pumps would draw fuel from the tank. So here is the deal. I was concerned with why it wouldn't flow from the rear to the front. Well it was it just wasn't allowed to flow any further because of the clog ahead. The fuel filter in the carb was jammed up so bad it wouldn't allow any fuel to work it's way upstream it just sent it back through the return line. So now that I was working with a electric pump with no return line. It couldn't be sent back. Here's the interesting part. The clog that was in the filter in the carb looked like red clay. The filter had been plugged bad. So bad that it wouldn't allow fuel to be pulled down the line from the tank. Interesting fact.... Clear inline fuel filter didn't stop any of this. AC delco fuel filter in the carb stopped it. I now know the clear inline fuel filters are no more than fuel sight plugs. Going back to the red clay type stuff anyone? Anyone? What in the world might this be?