You're not confused, you are correct.
Modifying stock fuel lines?
- Thread starter MNwe4
- Start date
You're not confused, you are correct.
The return line might need to be modified if you send a lot more fuel to the motor than it can use. The DW and TT 340 and anything bigger might necessitate this modification if you run gasoline. If you run E85,you probably won't have to modify.. A 255 lph pump or a double 255 lph pump set-up doesn't overpower the return line because neither set-up sends a lot more fuel to the motor than it can use at any given time.
Yes,you would still be able to use the O-rings.
So after my G7 Double Pumper install (w/Aeromotive Pumps) my idle pressure couldn't go below 53psi. Last night I drilled out these two fittings as large as I could go with out destroying the fitting. The lower fitting is TINY, literally a straw from 7-11 is nearly twice as big! I was able to drill out the top one a 15/64 or 0.2344 & the bottom one to 11/64 or 0.1719.
This return line is just tiny, to go SUPER CHEAP you could "possibly" get away with adding 90° Elbow, 3/8" Male JIC x M14x1.5 Male Metric, #6 to 5/16" barb 4 feet of 5/16" high pressure hose, cut that Saginaw fitting OFF, flare the 3/8" pipe and use a dual hose clap setup (which is what your using if you're using the stock hat now back at the tank)
I would never do the above but it was just an idea for someone on a very sensitive budget if drilling didn't solve the problem.
However if the above hadn't lowered my fuel pressure then yeah I'd do the below.
"The fitting on the bottom of the regulator came from www.discounthydraulichose.com and is part# 9069-06-14 (90° Elbow, 3/8" Male JIC x M14x1.5 Male Metric Adj. (Steel))
That will allow you to connect a -6 AN female hose to the bottom of the regulator.
The -6 hose is from NOS. I ordered it from Summit Racing, part 15480NOS. 16ft long. (Jegs also has this-I ordered it from Jegs with the fitting below)
The fitting at the end of the hose is a -6AN Male to 5/16" Barb, which I got from Jegs, part # 027-15635. You could most likely get the hose there also.
Then I bought a short piece of 5/16" efi fuel hose, like a foot long, to connect to the original return line above the rear axle (try to find some J30R9 hose, or J30R10 is even better). Now the problem is, the original return line is 1/4", so the 5/16" hose is a little big. So I put 2 clamps on there to make sure it doesn't leak. I don't really like that idea, but at the time, I could not find a -6AN male to 1/4" barb adapter.
So that's pretty much it: the regulator to -6 adapter, the 16ft -6 hose, and the -6 hose barb adapter. I'm sure there are other ways to do it, but this worked well to get the idle pressure down"
This return line is just tiny, to go SUPER CHEAP you could "possibly" get away with adding 90° Elbow, 3/8" Male JIC x M14x1.5 Male Metric, #6 to 5/16" barb 4 feet of 5/16" high pressure hose, cut that Saginaw fitting OFF, flare the 3/8" pipe and use a dual hose clap setup (which is what your using if you're using the stock hat now back at the tank)
I would never do the above but it was just an idea for someone on a very sensitive budget if drilling didn't solve the problem.
However if the above hadn't lowered my fuel pressure then yeah I'd do the below.
"The fitting on the bottom of the regulator came from www.discounthydraulichose.com and is part# 9069-06-14 (90° Elbow, 3/8" Male JIC x M14x1.5 Male Metric Adj. (Steel))
That will allow you to connect a -6 AN female hose to the bottom of the regulator.
The -6 hose is from NOS. I ordered it from Summit Racing, part 15480NOS. 16ft long. (Jegs also has this-I ordered it from Jegs with the fitting below)
The fitting at the end of the hose is a -6AN Male to 5/16" Barb, which I got from Jegs, part # 027-15635. You could most likely get the hose there also.
Then I bought a short piece of 5/16" efi fuel hose, like a foot long, to connect to the original return line above the rear axle (try to find some J30R9 hose, or J30R10 is even better). Now the problem is, the original return line is 1/4", so the 5/16" hose is a little big. So I put 2 clamps on there to make sure it doesn't leak. I don't really like that idea, but at the time, I could not find a -6AN male to 1/4" barb adapter.
So that's pretty much it: the regulator to -6 adapter, the 16ft -6 hose, and the -6 hose barb adapter. I'm sure there are other ways to do it, but this worked well to get the idle pressure down"
So you're saying that drilling the two Saginaw fittings on the return line fixed your high idle pressure caused by installing a high flow pump like the Walbro 340 or the DW.
As of right now, yes sir! I can't get the FP below 43.5 but the computer can deal with it and the car is driving GREAT! Like some have said, this doesn't fix it for everyone but it fixed it for me. Thinking about it, if I drilled out the feed side Saginaw fittings it may go back to being too much pressure.
Hope the pictures help someone out, they sure would have helped me.
Hope the pictures help someone out, they sure would have helped me.
It's not a restriction at low rpm. It becomes a restriction when we try to move more and more fuel through the lines. your motor isn't requiring that kind of fuel yet.
sakudog said:
Thanks for posting this! I may be tapping you on the shoulder soon for advice since i just ordered the same setup as you only with 255 lph's. They also convinced me to go for the AN fittings (just in case i later want to upgrade lines), so i will need to pick up the adaptors to go from AN to the factory lines. Your post will allow me to pre-buy the fittings since I know the size of the lines!!! Thanks again!
You won't need to do this mod because your 255s wont overpower the return line.
I had to do the -6 return line mod after installing the DW301 Pump on my car. Once done-- I can control the ilde pressure w/o worries. If I would not have done this return line mod the idle pressure would not come down below 48lbs "line off" or "on"....All fixed now!
Did you,first,try drilling the two Saginaw fittings in the return line?
I've received many PMs from people with this problem. It's very common and yet Nick still implies that it doesn't exist. Eric Marshal warns his customers that it might be a problem if you buy his higher volume pump. That's to be admired.
Ok guys, time for an update! 
Bad news, my G7 (w/Aeromotives) blew the FPR o-ring out of the fuel rail last night after about 1 good 3 gear pull.
Good news, it's completely possible to upgrade the return line with out much expense & work and thus I am doing that either this weekend or next.
Bad news, my G7 (w/Aeromotives) blew the FPR o-ring out of the fuel rail last night after about 1 good 3 gear pull.
Good news, it's completely possible to upgrade the return line with out much expense & work and thus I am doing that either this weekend or next.
sakudog said:Ok guys, time for an update!
Bad news, my G7 (w/Aeromotives) blew the FPR o-ring out of the fuel rail last night after about 1 good 3 gear pull.
Good news, it's completely possible to upgrade the return line with out much expense & work and thus I am doing that either this weekend or next.
I dont see how this is possible. Once the regulator is bolted down the regulator can't move outward. The bolts must have been loose and backed off. Youre lucky the car didn't catch on fire
Bison,
After giving it more thought...
You could be right, honestly I have no way of knowing for sure if the o-ring was damaged or if the Accufab regulator that came with my car ever had the right o-ring. Lucky, I do have a new FPR that I will install tonight and take pictures of any irregularities I can find when comparing the two. Also, as a lesson my little stock TE60 motor does NOT need the 2nd pump so until I get the lines put on next weekend I'll just unplug the hobbs switch which I hope will allow me to enjoy the car on the current setup for a little while.
After giving it more thought...
You could be right, honestly I have no way of knowing for sure if the o-ring was damaged or if the Accufab regulator that came with my car ever had the right o-ring. Lucky, I do have a new FPR that I will install tonight and take pictures of any irregularities I can find when comparing the two. Also, as a lesson my little stock TE60 motor does NOT need the 2nd pump so until I get the lines put on next weekend I'll just unplug the hobbs switch which I hope will allow me to enjoy the car on the current setup for a little while.
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- Jun 11, 2009
Update on mine: Just did the -6 return with Slow91z and everything is fine again. Before fuel pressure would not rise to the amount boost (12psi max) and the lowest I could get was 48 to 50psi on the FP gauge. EXACTLY the same as jmendlik and I drilled out the return lines. I'll see how far these 80's and TT340 take me.
Thank you everyone for sharing their experiences so far. Since it seems to be hit or miss with the drilling I've decided to just hook up the system the way it was with the new pump and injectors. If luck isn't on my side then I'll just run new lines and call it good. Hoping to have the car running by the end of the month. I'll post back with my results as well.
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