CaptainKRM

iTrader: (3)

hey folks, did a search and came up dry - so i'm going to bite the bullet and risk being called a NEWB

i've got an 85 12a that i've installed one of Racing Beat's Holley carb kits on. The kit is designed for a non ported stock 12a and calls for a 6psi Mallory or equivalent fuel pump. it also calls for the leading vacuum advance to be tied into a vacuum source.

i've got one guy who says the carb does not need the mallory pump and the car will run better without it despite having the holley installed. he also states not to connect either of the vacuum advances.

i guess what i am looking for is any sound advice or experience in running this setup and just how valid either point is. any help will be greatly appreciated! thanks.

kgray

hmm... pump may be "bad" if the pressure it soo high for the holley, but should be about right. If not, regulate it down. The turbo guys disconnect the vacuum advance, but i'm not sure that there woule be great gain...

nick812

Holley blue fuel pump would be a good chooce for you. Pump is big enough for the holley and also comes with reglatior.

CaptainKRM

iTrader: (3)

the fuel pump is actually brand new OE mazda, so i know its not bad. i'm going to try tossing a wideband on the car later today or tomorrow and seeing how its running on the stock pump.

85rotarypower

The stock pump WILL NOT work. Its barely addequate for the stock Nikki carb, let alone a larger holley. Also, the stocker only puts out about 4psi or so, not enough for a holley. The holley blue mentioned above is a good choice.

As far as the vacuum advance on the dizzy, you need it hooked up for the engine to run properly. This needs to be hooked into a "timed" vacuum source. I believe this port can be found on the primary side metering block on a holley. You don't want to hook it up to manifold vacuum.

CaptainKRM

iTrader: (3)

thanks for the advice. i already have a 6psi mallory pump here as part of the kit, should i just use that or ditch it in favor of the holley blue? any particular spot that works well for an inline pump?

the directions call for trailing advance to be hooked up only (ignore my first eroneous post), and i've done some reading on the "yawpower" timing advance. any thoughts on that?

mattreeve

I used a regulator to regulate my pressure down to 3psi and Ive had no problems running the holley.

CaptainKRM

iTrader: (3)

ok i got the pump installed in line, in the engine bay. i wired it to the fuel pump relay wire on the driver's side but i believe it is not working properly. for one, now that it is wired in, all of my panic lights remain on. to me this would indicate poor ground. i have a tailpipe innovate wideband and it shows lean - REAL lean (like 20:1 to 16:1) - unless i floor it and go past 2000 rpm at which point it settles in the 14:1 and 15:1 range. i imagine if the ground is poor the pump will not operate properly.

so, more newb questions

does the pump need to be closer to the tank? what AFR should i be aiming for under partial and full throttle? has anyone chosen a different wire or way to power the pump other than the fuel pump relay wire?

thanks in advance!

mattreeve

I mounted my pump in the stock position using a seperate "hot" wire directly to my batt. from there I installed a relay connected to the old pump harness and new pump and wire, this made my pump work straight off the battery, giving the pump all the juice it needs from the battery and not taking any from the main system. Now when I was back there I removed the fuel control valve, This valve only shuts off the fuel when the car flips over which I dont plan on doing so. Also dont forget to place a good "inline fuel filter" before the pump so no crap gets in there, after that I have a regulator set at 3psi in the engine bay easily accessible to change when desired. Be sure theres no kinks in the fuel line.