Car struggles to make fuel pressure

Mitco39 · 05-25-2015, 09:10 AM

Quote:

Originally Posted by phunk

The over-tank transfer siphon is done with a venturi in the return line. It should put fuel on the passenger side of the tank faster than you burn it. The drivers side of the tank should be only 1" full before the passenger side even starts to go down. The exception would be if you just took a right turn and fuel sloshed over, then it would take several minutes for the siphon to recover the fuel to the passenger side again.

Fuel that comes back from the engine goes to a pair of venturi pumps, one is the overtank venturi and the other is the canister refill venturi.

The issues I been having are in a straight line out on the highway. When I pulled the pump I only had about a inch of fuel left in the tank (2 dots). Mind you after putting it all together and filling it up it was better, but I still wasn't completely happy with its performance as it did seem to still struggle somewhat.

Quote:

Originally Posted by phunk

Does your regulator have a vacuum line on it or a boost only line? Where is it hooked up? Does pressure raise at idle, and go down when you rev the engine?

I see that your fuel pump is red... is that a China knockoff 255? If so, you should replace that. Your fuel pump pickup should not be falling off.. get one that attaches properly to that pump with the circular lock how its supposed to be. The one you are using is for the stock pump.

Dont put holes in the bucket, no reason to do that.

You car should be running very lean if its actually dropping 10+psi fuel pressure from how it was tuned. Is your car running lean?

The regulator I have connected to a boost only line as suggested by you when I was installing the kit last year. It is connected to the boost tubes prior to the throttle bodies. It does try and follow the 1:1. Sits around 56-58PSI at idle which is what I set it for, then ramps up to ~65-66 or so under about 13 psi of boost. Maybe I am just asking for to much pressure out of that pump? It was fine for the first 6 or so months of running it that way.

I will have to check and see what pump is in the car, I was under the impression it was a quality pump but I will double check. If thats the case it could explain the issues.

Quote:

Originally Posted by phunk

Put a clamp on the return hose in the tank at the top fitting, and make sure a clamp is on the other side of the hose.

How long does it take your fuel pressure to drop to zero with the fuel pump off?

When I pull it back apart I will throw a clamp on there. And I dont know as I have my fuel pressure gauge hooked up and it only comes on when the key is turned on. I can have the wife pull the fuse for me and test it that way. I will do that this evening after work.

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