Fuel Pressure

[Steve Wood]

connect your vacuum gauge to the line going to the regulator and see what you read there.  If you read 19 in/hg at that point, It would seem the regulator is bad.

I take it that you saw nothing wrong when you took the regulator apart?

[Joel Russo]

Steve~  I read vacuume on the line going to the regulator.  I did not take the Accufab apart yet, I'll do it tomorrow.  What am I looking for in terms of a "bad regulator"?

[Steve Wood]

tear or cut in the diaphragm or it is stuck so it can not pull up when you apply vacuum to it.

[Joel Russo]

I pulled the Accufab apart and did not find a tear in the diaphragm.  Looked like the spring was in good order as well. 


I also pulled apart the Kenne Bell regulator that I replaced with the Accufab, and did not find anything wrong with it either.


I did notice that the vacuume port on the Accufab is quite a bit smaller inside diameter than the Kenne Bell.


Okay, so now what do I do?  Set pressure at 43 psi with vacuume line off and head down the road, or replace with the KB and see if pressure drops when I connect the vac line?

[PacecarTA]

its not the regulator , its the return line cant flow back what the hotwired walbro is supplying
im sure if you bypass the hotwire at the tank by plugging the pump back into the factory harness youll see the pressure drops


try opening up the return line ends (the opening of the  saginaw ends) with an awl  or a small drill bit , and check the line at the axle and tank for kinks

[Steve Wood]

Yep, sounds like the return line.  I guess the clue was in one of the earlier posts where you said the pressure would rise under boost but not drop.

Unless the ends are caked up with fuel deposits, there should be no need to enlarge the inside of the fittings.  My first guess would be a kinked hose at the axle on the return line or an internal collapse in the rubber line up front where the vertical down line from the regulator makes the 90 deg turn to go to the back.

Another possibility might be that the return line and the vapor line from the charcoal canister were swapped at the tank when a fuel pump change was made.

[Joel Russo]

its not the regulator , its the return line cant flow back what the hotwired walbro is supplying
im sure if you bypass the hotwire at the tank by plugging the pump back into the factory harness youll see the pressure drops


try opening up the return line ends (the opening of the  saginaw ends) with an awl  or a small drill bit , and check the line at the axle and tank for kinks

I bypassed the Hotwire and pressure reads 40 psi with the hose off, and 34 psi with the hose on.


Looks like the issue is when  I have the Hotwire connected.


So where do I go from here.  If I want to run the Hotwire is there an issue if I set the pressure at 43 psi with the hose off?

[Steve Wood]

You go to what Paul told you and I repeated...loo k for a blockage on the return line side and be sure the hoses are connected properly at the tank end...return line is in the middle as I recall

[Steve Wood]

if that is not proof that a hot wire works, I don't know what is 

[Joel Russo]

Just put the car up and checked the lines.  Return line does not have any kinks, and it is connected at the correct location at the tank.


 

[Steve Wood]

what about the inside of the two rubber lines and the inside of the steel lines?

You gonna have to find the blockage...you cannot look at the outside and find anything but a kink....take the line loose at the regulator and at the gas tank end and blow thru the line to see if it is clear.  Also blow into the end that goes into the tank after you pull the line off.  There is another section of rubber lines on top of the tank

[Joel Russo]

First off, thanks for your diligence in trying to help me figure this out.




If I remove the line that connects to the regulator and to the tank at the rear, and blow air into it, is that not the feed line?  I thought this was a return issue.


If the fp drops correctly with the vac line off bypassing the Hotwire, then does not drop when the Hotwire is connected, is there a blockage or is the return line not adequate to handle the amount of fuel being returned under the Hotwire?


Don't know if it's out of line, but I can be reach by phone if it's easier...
717-805-0940

[Steve Wood]

The return line screws into the bottom of the regulator.  the delivery line screws into the front of the fuel rail on the passenger side of the engine.  If you follow the two lines down the front of the engine, you will see them come together, make the turn with two rubber hoses, and then run to the rear of the car.

Remove the lower line from the regulator and blow thru it.  If the return line is not blocked then it should be more than adequate to handle a 255 lph pump like the walbros.  If you installed one of the higher output pumps like the TT pump that Eric sells, then it may not be large enuf.

[PacecarTA]

the fuel pump sock should be positioned to be pointing long end toward the float ,

[Joel Russo]

  If you installed one of the higher output pumps like the TT pump that Eric sells, then it may not be large enuf.

I blew air through the line and still have the same result with the Hotwire hooked up.


I bought the fuel pump from Eric at TT, it is a Walbro 255. 


I can't remember which way I positioned the sock, but I believe it was correct as it's easier to insert he hangar that way.