Modifying stock fuel lines?

[TT/Ameasap]

Im going to be running stock lines in about 2 weeks. I am putting a S60 rear end in my car in a couple months, so when I have the rear out of the car, I can put my sumped tank in. But for now 15psi and E85 with 340 pump and stock lines on a T63 PTE .63ex.

 

[Chevman2448]

I have fuel issues as well. I have blown out '3" Kirbans FPR diaphragms (ill post pictures if you want). I am using a DW301 pump as well. It seems there is too much pressure in the system for the diaphragms. The diaphragms are holding the initial 40-45 psi i have the FPR set at but when I try to start the car the pressure rises to 60 or above and then gas starts shooting out of the vacuum line on the FPR. Im going to be switching from the OEM return line to a -6 return to alleviate the pressure. I think that my -8 feed from my fuel filter to the regulator is not helping the situation. It also didnt help that my vent line was blocked somewhere. I disconnected the vent line from the tank and shot compressed air into the line. I heard a pop and the line was clear.

 

[turbo89]

I have fuel issues as well. I have blown out '3" Kirbans FPR diaphragms (ill post pictures if you want). I am using a DW301 pump as well. It seems there is too much pressure in the system for the diaphragms. The diaphragms are holding the initial 40-45 psi i have the FPR set at but when I try to start the car the pressure rises to 60 or above and then gas starts shooting out of the vacuum line on the FPR. Im going to be switching from the OEM return line to a -6 return to alleviate the pressure. I think that my -8 feed from my fuel filter to the regulator is not helping the situation. It also didnt help that my vent line was blocked somewhere. I disconnected the vent line from the tank and shot compressed air into the line. I heard a pop and the line was clear.

I use that pump all the time with many customers cars... can't even tell you how many cars running around with that pump..
almost all of them are running 100% stock lines with no issues ... make sure you remove ALL the restrictions in your stock return line and you shouldn't have issues

 

[LSTTYPE]

What about using the vent line back to the tank as a secondary fuel return line? I thought other people were doing this to cure the return restrictions???

 

[Chevman2448]

I thought about using the vent line for that purpose. Then I have to cut the line and move stuff around and all that. It might be more expensive but the end result with the -6 line will be an easier move. Plus if I have upgrades later its almost prepared for anything I throw at it. Though I really would like to use that extra $100 for something else. You know I may just try that first. Im just worried I will buy another diaphragm and the damn thing wont be able to handle the pressure again. A -6 line would probably eliminate that uncertainty. I also use a hotwire kit (and an LT1 alternator) so It may have more boost then the pump needs.

 

[Boost231]

We use the vent as the new feed, and the old feed as the return

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[turbo89]

I thought about using the vent line for that purpose. Then I have to cut the line and move stuff around and all that. It might be more expensive but the end result with the -6 line will be an easier move. Plus if I have upgrades later its almost prepared for anything I throw at it. Though I really would like to use that extra $100 for something else. You know I may just try that first. Im just worried I will buy another diaphragm and the damn thing wont be able to handle the pressure again. A -6 line would probably eliminate that uncertainty. I also use a hotwire kit (and an LT1 alternator) so It may have more boost then the pump needs.

the power you have going to the pump is exactly what you want ..
I would spend some time and look at the entire return line carefully.. make sure you have removed all restrictions from the line ... the car should maintain 45 psi no problem.
If your diaphragm is rupturing @ 60 psi ... what will you do when you ramp the car upto 20 psi of boost ... as it will be OVER 60 psi at the regulator...

you sure there isn't something going on with your regulator ?

 

[LSTTYPE]

It doesn't look like anything will have to be cut. Looks like you can T in at the return rail, then get rid of the canister, and run a high pressure fuel hose a couple feet long to the fuel return line on the passenger front frame. No cutting necessary. I'm guessing you could then use a vented fuel cap and be done??? I can't get my fp regulated down either so I'm going to try this. I'm running a dw fuel pump and 80 lb injectors. My fp is ranging between 48 to 55 psi at idle with no control of fp. When I disconnect my hotwire to the pump and run off the stock harness, the fp goes back down to 42 at idle and is adjustable.

 

[turbo89]

It doesn't look like anything will have to be cut. Looks like you can T in at the return rail, then get rid of the canister, and run a high pressure fuel hose a couple feet long to the fuel return line on the passenger front frame. No cutting necessary. I'm guessing you could then use a vented fuel cap and be done??? I can't get my fp regulated down either so I'm going to try this. I'm running a dw fuel pump and 80 lb injectors. My fp is ranging between 48 to 55 psi at idle with no control of fp. When I disconnect my hotwire to the pump and run off the stock harness, the fp goes back down to 42 at idle and is adjustable.

IF you are on E85 ... leave it at 48 psi with those injectors .. I would tune around that base psi and even 50 psi

Did you address all the restrictions in your return line ?

 

[LSTTYPE]

Other than drilling at the Saginaw fittings I don't know what other restrictions there could be???

 

[Slow91z]

Clogged or kinked lines, if the vent was plugged why would you think the return couldn't be.

 

[Chevman2448]

Im

the power you have going to the pump is exactly what you want ..
I would spend some time and look at the entire return line carefully.. make sure you have removed all restrictions from the line ... the car should maintain 45 psi no problem.
If your diaphragm is rupturing @ 60 psi ... what will you do when you ramp the car upto 20 psi of boost ... as it will be OVER 60 psi at the regulator...

you sure there isn't something going on with your regulator ?

Im not sure if there is anything wrong with the regulator besides the diaphragm of course. I checked the vent and return line for them being plugged. The return line wasnt but the vent line was. Now they are free and clear. I switched the vent and return lines this afternoon. I cant tell if pressure is good or not since I dont have a good diaphragm to check it with. Though I did pressurize the system and start the car. While it was running I would periodically touch the pump hotwire lead to the alternator (good idea? Likely not) and it stayed running for a while. Until I discovered a leak from the turbo oil return line. When it rains it pours I guess. I did look at it closer though and the pressure is jumping over 80 when the diaphragm is rupturing.
When i get a new diaphragm Im going to disconnect the hotwire and see what that does. After I get that oil leak fixed!!

 

[Chevman2448]

Update.....Is there supposed to be a check ball in the return line on a racetronix fuel sending unit? I finally dropped the tank and took it all apart to find the tube fully blocked by a metal check ball (i know its metal I tried drilling it out). There was no flow through either direction no matter what I did. I figured it wasnt supposed to be there so I started drilling it out. There is no way that I pushed that through the fuel line already on the car when I blew air into the fuel lines. It looks like a ball bearing and was stuck near the fuel level sender arm would be.

 

[turbo89]

Update.....Is there supposed to be a check ball in the return line on a racetronix fuel sending unit? I finally dropped the tank and took it all apart to find the tube fully blocked by a metal check ball (i know its metal I tried drilling it out). There was no flow through either direction no matter what I did. I figured it wasnt supposed to be there so I started drilling it out. There is no way that I pushed that through the fuel line already on the car when I blew air into the fuel lines. It looks like a ball bearing and was stuck near the fuel level sender arm would be.

that will do it .. small things cause big problems !

 

[Chevman2448]

The ball is actually ceramic, I tried heating it up with a torch.

 

[83 intercooled]

Oh