klu-less

i have an 86 IROC that was converted from TPI to carburated. the cam was not changed out so, an electric fuel pump had to be added (TPI cam missing lobe to drive mech. pump). the pump was placed in the engine compartment......anyway, i was having problems with the car bogging down on me and i was told my carburator had some junk in it that would intermittently get lodged in the carb jets, making it bog down, die out. i replaced the carb with a new edelbrock carb and it ran fine for a few hrs a day. on an off day from work i took it for a long cruise and it started acting up on me again. the pump is new, i have replaced the carb filter and the in line filter under the car too. does anyone have an idea what may be causing this? i was told it could be vapor lock but, how can i tell? i was gonna relocate the fuel pump this weekend until i can get the mechanical one active.......thanks in advance.

EvilCartman

iTrader: (1)

Electric fuel pumps are better at pushing the fuel instead of pulling it all the way from the tank to the front. Mount it as close to the tank as you can.

Chris5k

What kind of pressure is that pump putting out? you should only need 5-7 psi to your carb, too much pressure could cause flooding and bogging.

Lo-tec

What happened to the factory in-tank pump? Is it in the tank but disconnected? You can replace it with a TBI pump and regulate it down to 5-6 psi.

klu-less

yeah, still in the trunk as far as i know. not too sure about how much pressure is being pumped out, i'd have to check......i am gonna relocate to the rear of car next to tank this weekend. thanks. maybe i should just get the cam replaced and the mech. pump running instead? what kind of money are we looking at? my mechanic charges me $30/hr (cheap around here).

Lo-tec

If it's a tpi car, puts out 45-50 psi easy. Drop the tank, throw in a TBI pump, and use a cheap holley regulator (the one that comes with a blue pump) to regulate down to 5 psi. Put a fitting on one port of regulator with a restriction in it (small pinhole) for a return to tank and mount on the block where fuel pump goes. I don't think you want to be using an external pump sucking through the stock pump in the tank.

83 Crossfire TA

iTrader: (2)

The pinhole is important there because without it you’ll kill that pump quickly deadheading it.

You might be able to regulate down the TPI style pump to a usable pressure using either a slightly modified aftermarket FI style regulator (Mallory has one that will go that low, otherwise pop it open, pull out the preload spring and either trim it or crush it in a vice), reassemble and hook it up just like any other FI/bypass style regulator.

You should be able to do the same with any of the $$$ carbureted bypass regulators and if you’re not particularly good at rigging this kind of stuff it will probably end up costing you less in the long run also

Lo-tec

Holley Part # 12-803. Fitting in this was available through gm. Was used on the ZZ crate motor kit for camaro. Email me monday and I'll see if still available and part #. Other side of regulator without fitting would go to carb. Bolted to bottom two holes on fuel pump block off plate.

xpndbl3

iTrader: (5)

that holley regulator is not a return style regulator and will burn up his TPI pump quickly. he needs mallory #4309 return style regulator.

Lo-tec

This holley regulator IS converted into a return style regulator cheaply as shown. It has 1 port in and 2 regulated ports out. The 2nd port out uses a fitting with a small pinhole (.020" or .030") to return the fuel. This is the setup GM sold in the ZZ motor kit for the mid 80's camaro. The fitting in the pix is the one from GM. I ran this for a while with no problems, no fried pump. The fitting on the top in pix is inlet from pump, fitting on left is the restricted return to tank. Missing from regulator in pix is outlet fitting to carb.

Lo-tec

Also, he needs a TBI pump, not the TPI pump in his tank now. Either way he has to pull the tank, so he should put in the right pump and regulate it down (regulator costs $25.00 from summit) and be done with it.

83 Crossfire TA

iTrader: (2)

Man, you’re all a big, freaking pain in the ***.

*******, your holley setup uses the bleed hole to keep fuel flowing through the system to keep from deadheading the fuel pump. It works for that setup but is not the most efficient way of doing things. With a higher flowing pump like the TPI pump the bypass/bleed would have to be larger. The problem is that you end up needing a good amount of pump for a fairly small amount of total fuel flow, and I’m not really sure that the setup will ever really be happy with a TPI pump.

An easier setup with any intank fuel pump would be to just get a carbureted bypass style regulator (look at barry grant, aeromotive…, or like I mentioned, with a little creativity you could modify a more common FI style regulator to work). As long as the pressure coming into the regulator is higher then the pressure you need for the carb this setup will work. Yea, you’ll pay roughly $100 for one of these regulators, but going with the holley setup will run you about $20-30 for the regulator and another $100 or so for the pump plus a ton more work. Hell, if I remember right there’s an aeromotive regulator that comes with swappable springs that will work from 3-65psi and a port for a boost reference line if you wanted to use it, so with that one you’ll pretty much be covered no matter what you end up doing with the engine.

83 Crossfire TA

iTrader: (2)

Heh, funny, Tim, the second part of your screen name is censored on this board