Losing Fuel Pressure

Old 11-26-2009, 06:54 PM
  #1  
skipjobe
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Default Losing Fuel Pressure

I have a 383 fuel injected with a rear mount gt45 about ready to go to the tuner, it has a mail order start up tune. I have been trying to get the car ready for a dyno tune. Here is my problem. The car is running very fat 10to 1 AFR. I have been running the car against the line lock and at about 4000RPM the fuel pressure drops about 20 pounds to about 20 to 25PSI. I am running two Walbro pumps on two different circuits. I checked all the fuel lines and the fuel filter and actually changed the line between the pump and the fuel filter because the line had a couple kinks. Any suggestions would be appreaciated.
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Old 11-26-2009, 07:39 PM
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DirkaDirka
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Does the car have a fuel cell? If so does it have foam in it?? If so how old is the foam?? The foam could be clogging up the fuel pick up at the pump.
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Old 11-27-2009, 03:49 AM
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skipjobe
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Default Fuel

It is a stock tank that is clean.
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Old 11-27-2009, 07:18 PM
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Default Pump

Put an order for an Aeromotive A1000 today I hope that solves my problem.
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Old 11-27-2009, 09:01 PM
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Default Re: Losing Fuel Pressure

Originally Posted by skipjobe
I have a 383 fuel injected with a rear mount gt45 about ready to go to the tuner, it has a mail order start up tune. I have been trying to get the car ready for a dyno tune. Here is my problem. The car is running very fat 10to 1 AFR. I have been running the car against the line lock and at about 4000RPM the fuel pressure drops about 20 pounds to about 20 to 25PSI. I am running two Walbro pumps on two different circuits. I checked all the fuel lines and the fuel filter and actually changed the line between the pump and the fuel filter because the line had a couple kinks. Any suggestions would be appreaciated.
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Fat? You mean lean right?
What size lines do you have going to the pumps and reg?


Do you have a bypass or a vacuum controled regulator?
Sounds like a fuel regulator problem to me.
On a Vacuum controled unit , make sure you have full manifoild vacuum going to it.
Also check for a voltage drop to the pump(s) and also the pump grounds.


Cp
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Old 11-28-2009, 04:58 AM
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hammertime
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How about a new guage to check the pressure ?

AF is fat and is not where it should be, what type of monitor do you have on this ?
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Old 11-28-2009, 11:47 AM
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gnsrule
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What Walbrow pumps you got? I asume 340m. With 2 pumps running 2 feed lines to what, each side of the rail with what, 1 reg on the left side and what size return line? What size feed line? What injectors? How about a hot wire with a relayd good 12v close to the pump.

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Old 11-28-2009, 05:49 PM
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skipjobe
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Default fuel

I have a wide band (Innovate LC-1) 2 Walbro 340's with a y in the tank to the stock 3/8 stock fuel line. The regulator is a factory stock with a kit to make it adjustable. It has a vacuum line to increase fuel. It also has a return line. I have #12 wire on a relay running to one pump and the stock circuit to the other. It is idleing at about 10 to 1 I am running it up on the line lock and watching the tack and someone is watching the fuel pressure under the hood, so I cant watch the AFR or boost to much going on.
Last night I ordered an Aeromotive a1000 pump and matching regulator.
I am hoping this will solve my problem. Next will be 1/2 inch hose and modify the fuel rails to a double inlet. I need my money tree to have another crop.
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Old 11-29-2009, 01:11 AM
  #9  
gnsrule
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Id stick with the walbro's befor id run an aeromotive junk. Intank double pumpers are suposed to be staged. Only run 1 at idle and cruize but turn on the 2nd at full throttle.
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Old 11-29-2009, 01:12 AM
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After rereading your setup, your gonna need at least a #10 feed and a 6 return. I run a Weldon 2015 pump on the 86 GN with enuff fuel to break the crank @ 35 lbs boost :roll:
You might wanna run the 2025-a.
I'd return the aeromotive and get a weldon, there suposed to be the slick shit. A little pricey, but you only wanna do it once
http://www.weldonracing.com/product/...Outlet%29.html

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