Electric fuel pump hookup for drag race only

[Stanley]

Had a miss at 4500 rpm 2 weeks ago at S.I.R. dragstrip. Repeated it (with backfire) at 4500 in 2nd, flat-out from stop a few times around here.

Car (mostly stock 73 240z, automatic, early SU's, euro dist, clean balance tube, best run 15.68 sec) runs strong otherwise, never misses at 4500 or higher when cruising. After checking other posts here and elsewhere, figure I might get a Mallory comp70 LP to replace the one by the tank (which doesn't seem to work - no sound by broomstick method). Yes, checking ignition, filters, will switch to NGK, etc., but might still need help with g-force on gas in small stock fuel lines.

Would like to hook it up with a switch to use for drag racing only, mechanical one seems fine for everyday (hard) driving, but afraid to race until it's fixed. I'm not great with wiring, relays, etc, but my mechanic is. Anybody have ideas/ experience for this?

Stan - 39 forever

[Stanley]

No money for pump or mechanic right now, so guess I'll do what my dad suggests: take the old elect. one off, clean it out, shine up the contacts etc and try it again. Saw a diagram of a setup with a switch but should probably ask advice from Mallory, when I get paid. Guess the Civics will win til it's sorted out.

[zKars]

If the rear elec. pump is not working, I'de try just bypassing it first. It may be quite a restriction to the suction side of the mechanical pump if its stopped. Does sound like your running out of fuel when the demand is high during racing (foot on floor I assume).

The rear electric pump has has an inline fuse under the dash onthe passenger side right behind/above the console/radio area. There is one for the pump and other for the defrost. There are NOT in the regular fuse box of 10. Might as well check those first before doing anything!

[Stanley]

Found the fuses, one with blue/white wires and one with red/white. Fuses looked ok, check them later. Should be able to check continuity - might need the ignition on if it goes through a relay.

Spent a half hour under the car staring at the pump and all the hoses til it dawned on me that bypassing it is a three-minute job, even for me. Will do that tomorrow when I get some new clamps. Did notice a hose next to the filler hose, a vent I guess, that was krinked where it went on top of the tank, probably no big deal. Thanks, zKars.

[Stanley]

The dire deed is done. "Transistor fuel pump" by Jidosha Kiki., Ltd. is outa there. Did I really say 3 minutes? Good thing too, that lower hose to the tank was garbage, ready to let go in about 5 places. Wiggled it slightly and it broke. The upper one, now hooked to tank, was ok, replaced I guess, why didn't they change the lower one? Says on there to change the filter every 12000 miles. Check that hose, people.

[Stanley]

Time to put this thread to bed. Turned out it was junk in the tank plus (3!) kinked vent hoses. All good now. Also, when I pulled the old electric, should have put a filter there immediately so the steel line wouldn't get clogged. The old pump works - bullet contacts just corroded.