Hello all,
Not sure if this should be in the carb forum or here.

Still have the IROC, but picked up a ‘87 black/tan cloth Monte Carlo SS as a bit of a retirement project.

The poor L69 305 is very noisy, & I swapped to a 5.7 L31.

I’m using a non-computer HEI, Vortec-style intake & non computer Quadrajet. The minor dilemma is the stock L31 cam doesn’t have a mechanical fuel pump lobe, nor is the block drilled for it.

I’ve read about a few smaller builds where a low HP engine with a low pressure non-regulated electric fuel pump will be adequate for a driver.

All this to say, can anyone recommend a “quality” low pressure 5 -7 lb non-regulated external fuel pump relay & wiring kit?

There seems to be a myriad of stuff out there, just not sure of chinesium electrical components these days.

I do know the key-on 12V to the fuel pump relay coil should be routed through the oil pressure switch to be safe.

Thanks

 

There is no such thing.

I did this in my BROTHER'S BOAT, you can see the pump in the second pic in post #16...I thought it was a Holley, but it's a rotary style pump that is rated at <7 PSI....however, it still pushed fuel through the needles and seats on the Edelbrock Carb that he had, and would flood the engine. Tried adjusting the floats lower and it still did it, so I had to buy a non-return style regulator, and that has worked so far (1.5 summers). The pump has been reliable...the regulator has too (much to my surprise).

I don't expect either to last long. Those regulators suck, and I've seen 'em fail almost immediately. The pump get's way "Bogged down" when it hits regulated pressure and essentially dead heads against the regulator. If it were MY boat, I'd put a return style regulator in, and simply loop the return line to a "T", right before the pump inlet to save running a return line. That would lower the load on the pump and work great for years, I'm sure.

 

In my opinion there is no external electric fuel pump that will last a long time or be very reliable for gasoline use. I've tried numerous types over the years and been disappointed or left broken down from all of them. For occasional or very local, limited use they might be okay, but I value longevity and dependability over price or convenience so I want to be able to hop into any of my vehicles and drive across the country without being stranded in the middle of nowhere. An increasingly tall order for any 30+ year old vehicle running on Chinese parts.

However, with no option to mount a mechanical pump and no need for an immersed high pressure pump I understand your predicament. I would probably go with your typical parts store electric external pump and get a return style regulator. Before buying regulator you could even just try making the fuel line unlimited return. Add a T fitting by the carb, or wherever is safe, and allow all excess pressure to return to the tank unregulated. I have had success with that on low fuel demand engines. Maybe don't travel much more than 50 miles from home without a spare pump and tools to swap out.

 

these work great.

https://www.autozone.com/p/edelbrock...p-17301/880185

 

Thank you for your replies. I have to get this sorted out.

 

Agree^^

I've had ^those^ STB on me, too.



Any of that type of pump is cheap enough; you could probably install two, in parallel, hook only one up, electrically speaking, leave the other set up w/the same kind of connector so when the first takes a dump, you could simply open the hood, unplug the one pump and plug the wiring into the second pump....then go burn some rubber. (And go buy another back up pump)

I would do something like Aaron said with the return, either way, to lessen the load on the pump.

 

Would another approach be to use replacement fuel tank and factory in-tank fuel pump from a late 80s TBI V6 Monte Carlo?

I have an unused 4309 Mallory fuel reg.

Should’ve just drilled out the pushrod hole & swapped a cam with a mech fuel pump lobe before the swap.

Reliability is the goal now.

 

Any OEM, or OEM replacement, in-tank pump, with a return style regulator would be the most reliable solution.

 

Agreed.
Would the existing standard carb’d ‘87 non baffled fuel tank work if a ‘88 V6 TBI in-tank pump & my shelf Mallory 4309 reg is used?

 

I can't see why that wouldn't work. You could even mount the regulator IN the tank and simply set it, and then let it dump immediately back into the tank....IN the tank. Save yourself running return lines if you don't already have 'em in the car.

 

Thank you Tom 400,
Could retrofitting an in-tank OEM 5-7 lb Vega fuel pump
without using a regulator be feasible?

 

IDK. Maybe? I thought that <7 lb pump I bought for that boat would work, but it didn't. It also pushed about 9 lbs. I'd have thought a <7 lb pump would be <7 lbs...and I'd think float needls could tolerate 9 lbs....especially when you lower the float, but they couldn't in that carb. So....i would plan for that to NOT work.

 

In the past I used a low pressure fender well mounted fuel pump but I plumbed it into the stock mech pump (with no provision for a fuel pump rod in the block)

the stock mech pump didn't pump, of course, but allowed excess fuel to flow back through the stock return line to the tank and kept the q-jet happy.

confirmed return fuel flow when running. ran it for years like that.

you may want to try it. a regulator can always be added later if it doesn't work for you.

 

From my own experience.........I had a mechanical pump fail and lock up on my 250hp daily driver years ago. After some troubleshooting I realized it had ruined the pump eccentric on the cam. I installed a Mr. Gasket 42s pump in the line up front under my radiator support. Daily drove that thing for probably 8 more years with zero issues. I parked it for other reasons and needed to move it 2 years later.........PUMP STILL WORKED!! I had to replace some rotted fuel hose cause fuel was leaking everywhere but then drove it around the property to my shop. My vote for ANYTHING carbed is the 42s. I even installed one for my neighbor in his old IH tractor after I derusted his gas tank and rebuilt the carb!!

 

Thank you tom400, naf & roadthrills,

I realize a late 880 1 piece RMS factory hyd roller cam is a better machined engine, but it does cause a minor snowball install effect compared to an older mech fuel pump equipped block.

Amazed to hear a eng compartment mounted external electric pump actually worked & LASTED. Was always told to mount the pump near the tank to push & not pull.

For ultimate reliability it looks like swapping in a new ‘85 Monte TBI baffled tank & fuel pump strainer assembly and use a pressure regulator? $$$$

I’ll have to check on this Mr Gasket 42s pump. Thank you!

 

I also read on an RV forum (guys talking about generators) that the Airtex E8251 is also a solid self priming pump for carbs.

 

IMO the best solution is, as you say, the in-tank pump utilizing a bypass regulator with return.