i bought a new holley fuel pump (same one in the my generation camaro in CHP) and it only has two lines. im guessing that it lacks the fuel tank return line. if i install this, what do i do about the return line? will it bother my emissions? should i notice a greater flow of fuel even though the intank fuel pump sucks?

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1987 LG4 Camaro z28

Performance
KN airfilter, flowmaster 80 series and catco high flow converter, 180* thermostat, edelbrock performer intake, msd blaster coil

System
Panasonic CQ-DF200U deck, fosgate speakers (hpc1369, frc2246), fosgate 400a4 amp

 

I'm assuming you have an external Holley pump, blue or red. Red is regulated, blue comes with a regulator. You mount the pump in the supply line close to the tank. You need to drop the tank and remove the factory in-tank pump.

Where does the factory return line come from? Carb, TPI, TBI? You usually just plug it off on a carb, leave it alone for fuel injected.

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and check out the race car

87 IROC-Z SuperPro ET Bracket Race Car
461 naturally aspirated Big Block (times are for the current engine)

Best ET on a time slip: 11.447 altitude corrected to 10.99
Best MPH on a time slip: 119.42 altitude corrected to 124.86
Altitude corrected rear wheel HP: 493
Best 60 foot: 1.586

Racing at 3500 feet elevation with a typical race day over 5000 feet density altitude!
Member of the Calgary Drag Racing Association

87 IROC bracket car, 91 454SS daily driver, 95 Homebuilt Harley

 

im not sure where the return line comes from, but on my stock block mounted fuel pump it has three lines, one to the carb, one from the tank and the third from who knows where, it runs along the one that goes back to the tank. see my car has two fuel pumps, and the buildup on the 87 camaro (CHP) is just what im dealing with. since its carb i can just block it off? wouldnt that mess with my emissions, i thought the return line was there to return some of the fuel to the tank for (cooling purposes)?

 

Well, crap. I ordered the very fuel pump in question on Friday. My 85 IROC also has the return line, so apparently this pump isn't the one that I need--thanks Chevy High Performance. The return line, I assume, goes to the fuel tank "for purposes of emission control and to reduce vaor lock."

JamesC

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anyone?

 

To anyone using the Holley non-return fuel pump on a quadrajet carb it will screw up the carburetor operation. I played around with this over a period of two months. I tried it in my '84Z28 with the HO 4bbl carb. I'm pretty sure that's what you are using James(how's it goin' by the way?) I tried a fuel pressure regulator to keep the pressure at 4,5,6,or 7 and the car would crap out at 4200rpm when before it was doing better(5500rpm). I ended up buying a stock replacement from Autozone and the problem was solved. Still don't exactly know what was going on. I ended up getting two from Summit to see if the first was bad and they did the same thing. Summit took them back no questions asked. Good luck,
Craig

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84 Z28 305HO, 5spd, 222,000 miles, Edelbrock intake, Hedman headers, low restriction exh(w/cat), K&N air filter, 14.630 at 93.17mph
Del-A-lum front control arm bushings, Moog ball-joints, Energy suspension front sway bar end links, Moog rear sway bar end links, Eibach pro-kit springs, tokico shocks/struts, AU secondary rods
www.indycamaro.com

[This message has been edited by Craig84Z (edited October 29, 2001).]

 

The return line is present on fuel pumps because the pumps are always capable of feeding more fuel volume than what the engine needs at a given time (except at the extreme high limit of the pump when it no longer can pump any more fuel volume at all).

An inline pump can be used with the factory pump still installed in the tank.... The factory pump in the tank is only a 'lift' pump and moves the fuel to the mechanical pump on the engine which provides the proper pressure and volume....

If you are installing an internally regulated inline fuel pump, you can block off the factory return line as it is no longer needed. Emissions control will not be affected by any of this - provided the carb is tuned properly and the pressure is set right.

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1987 GTA L98 MD8
355, TFS Heads, LT4 Hot Cam
My GTA

The Minnesota F-body Club

 

The problem you can run into is that the electric pumps don't keep a good vacuum on the line and it will loose it's prime. I have to reprime mine sometimes if i go more than a week. This is bc elect pumps are intended to be gravity feed and not have to draw a suction like mech pumps can. Without cutting the tank, it will be difficult to mount the pump at a point where it will get a gravity feed.

There is also the issue of the intank pickup like is 3/8 inch. That might not be sufficent to feed the motor. I used my return line as a second pickup (by extending it down to the bottom of the tank) with Y blocks to go back into 1 line.