For those running EFI - The 1947 - Present Chevrolet & GMC Truck Message Board Network

ABLAZN · 11-01-2007, 11:18 PM

For those running EFI, how did you run your return line into your stock thank? I have heard of one that T's into the filler neck, but I don't know where to find a kit if they make one.

Andy4639 · 11-02-2007, 12:53 AM

I used the vent line and tied into it.

earl87gta · 11-02-2007, 02:43 AM

here is the kit that summit sells http://store.summitracing.com/partde...5&autoview=sku

svgould · 11-02-2007, 03:28 AM

I used a 72 style sending unit....it has two tubes coming out the top. I used the normal one for the feed, and then made the other one longer inside of the tank and used it as a return.

Slammed70 · 11-02-2007, 09:45 AM

When you get your new tank to get it out of the cab....tell them you want a bung for the return line.

ABLAZN · 11-02-2007, 09:48 PM

Quote:

Originally Posted by earl87gta

here is the kit that summit sells http://store.summitracing.com/partde...5&autoview=sku

Thanks, I found that same kit after posting. The fuel sender idea sounds cool to.

Quote:

Originally Posted by Slammed70

When you get your new tank to get it out of the cab....tell them you want a bung for the return line.

No need to move my tank, this system is going in my Blazer, but if I ever replace the tank, that is the way I will go.

herb101 · 11-02-2007, 09:51 PM

I have heard that its better to return fuel to the bottom of the tank for a few reasons. One is aireation of the fuel - returning to the bottom ensures it flows into liquid. The other, and scarier one, is static discharge in the fuel vapor layer.

Never heard of a specific case on an issue, but every factory return setup I've seen has a return tube that dumps at the bottom of the tank.

Herb

Slammed70 · 11-02-2007, 10:02 PM

Quote:

Originally Posted by herb101

and scarier one, is static discharge in the fuel vapor layer.

Yeah, dont worry about that....its too "rich" in the tank with not enough oxygen to cause any problems.

**Boog** · 11-02-2007, 10:25 PM

I think a return line too close to the bottom will keep sediments stirred up making it easier to clog up the pickup screen.

DirtyLarry · 11-02-2007, 11:20 PM

Now for something completely different..... For my EFI project I will be running a mechanical fuel pump. Sounds weird to use a mechanical fuel pump for EFI but it is possible. If you use one of the new EFI mechanical fuel pumps you do not need to plumb a return line, which is a nice bonus plus you do not need to mess with wiring up one of those unreliable aftermarket electric fuel pumps. Check it out. http://www.racepumps.com/

Here is my project thread…
http://67-72chevytrucks.com/vboard/s...d.php?t=263323

boostat4500 · 11-02-2007, 11:40 PM

I bought a complete sending unit/pump setup for a 4th gen F-Body and put it in the stock tank. Gives you a feed and return port, and pressure regulator all in one. Plus it was only about 50 bucks.

Zonaman · 11-03-2007, 04:41 PM

Quote:

Originally Posted by DirtyLarry

Now for something completely different..... For my EFI project I will be running a mechanical fuel pump. Sounds weird to use a mechanical fuel pump for EFI but it is possible. If you use one of the new EFI mechanical fuel pumps you do not need to plumb a return line, which is a nice bonus plus you do not need to mess with wiring up one of those unreliable aftermarket electric fuel pumps. Check it out. http://www.racepumps.com/

Here is my project thread…
http://67-72chevytrucks.com/vboard/s...d.php?t=263323

Forgive my ingnorance here but how do you avoid the need for a return line- a regulator, what?

Thanks.

Ackattack · 11-03-2007, 06:06 PM

I hooked my return line up to the other fitting on the sending unit in my 72. Haven't had a problem with it (or the "unreliable" electric out of the tank fuel pump)

DirtyLarry · 11-03-2007, 06:08 PM

Yeah, something about the design of their variable displacement mechanical pump and regulator does not require a return line. Call’em up. They seem like real nice and informative people at racepump.com. I won’t have mine ready to fire up for a while yet.

ABLAZN · 11-03-2007, 10:28 PM

Quote:

Originally Posted by boostat4500

I bought a complete sending unit/pump setup for a 4th gen F-Body and put it in the stock tank. Gives you a feed and return port, and pressure regulator all in one. Plus it was only about 50 bucks.

I assume that was a used unit for that price. I looked at a couple on eBay, and there were a few in that price range for the LT1 engines. I might look into seeing if the in tank pump from my donor rig (1999 Tahoe) will fit, since it is all ready paid for and it can't hurt to try.

boostat4500 · 11-04-2007, 12:35 AM

Yes, it was used. I have replaced the pump since then with a bigger unit but still a great deal to get started. The unit from the Tahoe should work, just have to cut the appropriate sized hole in the tank. No big deal.

11-01-2007, 11:18 PM	#1
ABLAZN Oh..never mind.... Join Date: Aug 2006 Location: Oregon Posts: 588	For those running EFI For those running EFI, how did you run your return line into your stock thank? I have heard of one that T's into the filler neck, but I don't know where to find a kit if they make one. __________________ 1972 Blazer -6 inch lift -35 inch BFG A/T's Turbo 350 NP-205 454 BB (for now) MORE TO COME !!!!!! Now going to 2WD!!!!! Sold. I got it back after 22 years and did not even know it !!! THE STORY HERE Project Low Down Dirty Rat

11-02-2007, 12:53 AM	#2
Andy4639 Old member Join Date: Jan 2002 Location: Liberty, & Garden City S.C. , U.S. Posts: 19,945	Re: For those running EFI I used the vent line and tied into it. __________________ 1971 LWB Custom, 6.0LS & 4L80E, Speedhut.com GPS speedometer & gauges with A/C. 20" Boss 338's Grey wheels 4 wheel disc brakes. My Driver Seeing the USA in a 71 Upstate SC GM Truck Club 2013,14 and 2016 Hot Rod Pour Tour http://upstategmtrucks.com/ Get out and drive the truck this summer and have some fun! It sucks not being able to hear! LWB trucks rule, if you don't think so measure your SWB! After talking to tech support at Air Lift I have found out that the kit I need is 60811. Per the measurements I gave them. Ride height of truck inside spring and inside diameter of springs.

11-02-2007, 02:43 AM	#3
earl87gta Senior Member Join Date: Dec 2003 Location: Kingsport TN Posts: 4,641	Re: For those running EFI here is the kit that summit sells http://store.summitracing.com/partde...5&autoview=sku __________________ Earl 68 2500 4x4 GMC Burb

11-02-2007, 03:28 AM	#4
svgould Active Member Join Date: Jul 2003 Location: Boise Idaho Posts: 296	Re: For those running EFI I used a 72 style sending unit....it has two tubes coming out the top. I used the normal one for the feed, and then made the other one longer inside of the tank and used it as a return. __________________ 1971 SWB SOLD LT1 motor / 4l60E transmission ECE front dropped spindles with stock height springs 4" rear springs Coys Wheels 18 x 8 all the way around Hydratech hydroboost brake system

11-02-2007, 09:51 PM	#7
herb101 Used Register Join Date: May 2005 Location: Live Oak, TX Posts: 379	Re: For those running EFI I have heard that its better to return fuel to the bottom of the tank for a few reasons. One is aireation of the fuel - returning to the bottom ensures it flows into liquid. The other, and scarier one, is static discharge in the fuel vapor layer. Never heard of a specific case on an issue, but every factory return setup I've seen has a return tube that dumps at the bottom of the tank. Herb

11-02-2007, 10:25 PM	#9
Boog laying low Join Date: Mar 2001 Location: Searcy, Ark. USA Posts: 13,514	Re: For those running EFI I think a return line too close to the bottom will keep sediments stirred up making it easier to clog up the pickup screen. __________________ Boog 69 Chevy stepside, 358/T350, 4.11 posi, 4.5/4 drop, rallys, poboy driver primer is finer 91 Chevy sportside, Tahoe, Yukon & GMC Crewcab All GM..'nuff said. I stand for the flag and kneel at the cross

11-02-2007, 11:20 PM	#10
DirtyLarry Windy Corner of a Dirty Street Join Date: Jun 2003 Location: Pueblo West, Colorado Posts: 2,926	Re: For those running EFI Now for something completely different..... For my EFI project I will be running a mechanical fuel pump. Sounds weird to use a mechanical fuel pump for EFI but it is possible. If you use one of the new EFI mechanical fuel pumps you do not need to plumb a return line, which is a nice bonus plus you do not need to mess with wiring up one of those unreliable aftermarket electric fuel pumps. Check it out. http://www.racepumps.com/ Here is my project thread… http://67-72chevytrucks.com/vboard/s...d.php?t=263323 __________________ Current vehicle collection: 1978 Chevrolet K10, 8.1L, NV4500, NP205 1989 Chevrolet Suburban, 8.1L, NV4500, NP241 1993 Chevrolet C1500 Sportside, TBI 7.4L, 4L60E 2001 Chevrolet K2500HD, Ext Cab, SWB, 8.1L, ZF 6 speed 2014 Chevrolet Impala LTZ 3.6L Vortec 8.1L because life is too short to tolerate underpowered vehicles Instagram

11-02-2007, 11:40 PM	#11
boostat4500 Registered User Join Date: Aug 2006 Location: Reno, NV Posts: 346	Re: For those running EFI I bought a complete sending unit/pump setup for a 4th gen F-Body and put it in the stock tank. Gives you a feed and return port, and pressure regulator all in one. Plus it was only about 50 bucks. __________________ 1971 Suburban 4x4, LQ4 6.0L, 4L80E, etc.

11-03-2007, 06:06 PM	#13
Ackattack Senior Member Join Date: Aug 2002 Location: Valley Center KS Posts: 3,524	Re: For those running EFI I hooked my return line up to the other fitting on the sending unit in my 72. Haven't had a problem with it (or the "unreliable" electric out of the tank fuel pump) __________________ Project Bruiser: 68 Pro-Touring C-10 5.3L / 4L60E Project Ironhide: 97 GMC Crew Cab 4x4 Cummins SOLD: '69 GMC 1/2T SWB TBI'd: Project No Buck Assembly Manual Index Sign up Thread!!! Factory Service Manual Index

11-03-2007, 06:08 PM	#14
DirtyLarry Windy Corner of a Dirty Street Join Date: Jun 2003 Location: Pueblo West, Colorado Posts: 2,926	Re: For those running EFI Yeah, something about the design of their variable displacement mechanical pump and regulator does not require a return line. Call’em up. They seem like real nice and informative people at racepump.com. I won’t have mine ready to fire up for a while yet. __________________ Current vehicle collection: 1978 Chevrolet K10, 8.1L, NV4500, NP205 1989 Chevrolet Suburban, 8.1L, NV4500, NP241 1993 Chevrolet C1500 Sportside, TBI 7.4L, 4L60E 2001 Chevrolet K2500HD, Ext Cab, SWB, 8.1L, ZF 6 speed 2014 Chevrolet Impala LTZ 3.6L Vortec 8.1L because life is too short to tolerate underpowered vehicles Instagram

11-04-2007, 12:35 AM	#16
boostat4500 Registered User Join Date: Aug 2006 Location: Reno, NV Posts: 346	Re: For those running EFI Yes, it was used. I have replaced the pump since then with a bigger unit but still a great deal to get started. The unit from the Tahoe should work, just have to cut the appropriate sized hole in the tank. No big deal. __________________ 1971 Suburban 4x4, LQ4 6.0L, 4L80E, etc.

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