Looking for electric fuel pump control

Matt Colie

Matt Colie

Well-known member
Aug 15, 2008
11,101
807
113
South East Michigan near DTW
During the winter re-fit, I will be installing a pair of Carter 4070s.

I am mulling over how to control them so that when the main engine shuts down for any reason, they stop pumping.
I can think of lots of good reasons for this and trying to decide between alternator output (like I use for the electric choke), or lube oil pressure
present.
They should both be reliable and the alternator is less invasive.

If someone has a better idea, I should like to hear it before I buy more parts.

Thank You

Matt
--
Matt & Mary Colie - Chaumière -'73 Glacier 23 - Members GMCMI, GMCGL, GMCES
Electronically Controlled Quiet Engine Cooling Fan with OE Rear Drum Brakes with Applied Control Arms
SE Michigan - Near DTW - Twixt A2 and Detroit
 
Matt,

The problem with the alternator supply is that if the alt. fails, you're
dead in the water 'til you bypass the isolator. The oil pressure switch
(from a Vega), on the other hand, only shuts down the pump when the engine
initiates the shutdown.

Ken H.

> During the winter re-fit, I will be installing a pair of Carter 4070s.
>
> I am mulling over how to control them so that when the main engine shuts
> down for any reason, they stop pumping.
> I can think of lots of good reasons for this and trying to decide between
> alternator output (like I use for the electric choke), or lube oil pressure
> present.
> They should both be reliable and the alternator is less invasive.
>
> If someone has a better idea, I should like to hear it before I buy more
> parts.
>
> Thank You
>
> Matt
> --
> Matt & Mary Colie - Chaumière -'73 Glacier 23 - Members GMCMI, GMCGL,
> GMCES
> Electronically Controlled Quiet Engine Cooling Fan with OE Rear Drum
> Brakes with Applied Control Arms
> SE Michigan - Near DTW - Twixt A2 and Detroit
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
>
 
> Matt,
>
> The problem with the alternator supply is that if the alt. fails, you're dead in the water 'til you bypass the isolator. The oil pressure switch
> (from a Vega), on the other hand, only shuts down the pump when the engine initiates the shutdown.
>
> Ken H.

Ken,
I like the idea and the Vega switch had the other function of of powering up the pump with ignition on. But that was 50 years ago and I really don't
remember how it all worked and I don't have another place to add a pressure switch. All the regular pressure switches are normally open.
Anybody have any diagrams or part numbers?
Thanks
Matt
--
Matt & Mary Colie - Chaumière -'73 Glacier 23 - Members GMCMI, GMCGL, GMCES
Electronically Controlled Quiet Engine Cooling Fan with OE Rear Drum Brakes with Applied Control Arms
SE Michigan - Near DTW - Twixt A2 and Detroit
 
...and even if you jumper the outer terminals of the isolator (or have a combiner), the alternator output feed would still be dead along with your
fuel pumps. Wiring in an override switch would work, but it would carry the risk of leaving the switch in the override position, thus defeating the
safety feature. At least if such a switch were illuminated you'd be likely to notice when it was in the override position.

I vote for using oil pressure. That's how the PO set up the aux electric fuel pump on my coach, using an oil pressure switch and a relay so that the
pump will only run when switched on and there's oil pressure. The only thing I don't like is that I have a "tree" coming out of the oil pressure port
with one switch and two senders (for aftermarket dash gauge and DigiPanel. It's ugly.

Some folks have also used a "crash sensor" switch based on an accelerometer -- I don't know the OEM brand / part number -- to kill the pumps if
there's an accident.
--
Christo Darsch
GMC Nor'easters
1977 Eleganza II - "The Komet"
3.50 Power Drive, Disc Brakes, Alcoas
Weymouth, MA
 
Matt,

Here's a list of the applications for what I'm in the habit of calling a
"Vega Switch":
https://1drv.ms/t/s!Ai1vXmS6UF0_gotF3OLJPne3NDCh2w

And here is the diagram of my pumps, as I drew it in 2010:
https://1drv.ms/b/s!Ai1vXmS6UF0_gotLYbNzGmIJMNYfvA?e=md8n9j

Ken H.

> > Matt,
> >
> > The problem with the alternator supply is that if the alt. fails, you're
> dead in the water 'til you bypass the isolator. The oil pressure switch
> > (from a Vega), on the other hand, only shuts down the pump when the
> engine initiates the shutdown.
> >
> > Ken H.
>
> Ken,
> I like the idea and the Vega switch had the other function of of powering
> up the pump with ignition on. But that was 50 years ago and I really don't
> remember how it all worked and I don't have another place to add a
> pressure switch. All the regular pressure switches are normally open.
> Anybody have any diagrams or part numbers?
> Thanks
> Matt
> --
> Matt & Mary Colie - Chaumière -'73 Glacier 23 - Members GMCMI, GMCGL,
> GMCES
> Electronically Controlled Quiet Engine Cooling Fan with OE Rear Drum
> Brakes with Applied Control Arms
> SE Michigan - Near DTW - Twixt A2 and Detroit
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
>
 
G'day, I am in the process of swopping over to a pair of 4070's as well. I currently use a Facet copy pump as a booster pump which has a Peel CP30 LPG
controller wired in as a cut-off. I will now use this to control the 4070's. The CP30 works by allowing the fuel pump to run for approximately 2.5
seconds, when the ignition is turned on, then cuts-out until it detects a pulse from the distributer. Then if the Engine stops, so do the fuel pumps.
https://www.peelelectronics.com.au/lpg-automotive-gauges-propane-closed-loop-safety-switch/
--
Mark Bennett
Gail & Mark's Cruiser
Gold Coast, Australia.
Motorhoming Lifestyle.com
 
> Matt,
>
> Here's a list of the applications for what I'm in the habit of calling a
> "Vega Switch":
> https://1drv.ms/t/s!Ai1vXmS6UF0_gotF3OLJPne3NDCh2w
>
> And here is the diagram of my pumps, as I drew it in 2010:
> https://1drv.ms/b/s!Ai1vXmS6UF0_gotLYbNzGmIJMNYfvA?e=md8n9j
>
> Ken H.

Ken,

Your diagram has lots of good ideas that I may borrow. The diode AND gate is a great start.

What I have been hoping to locate is the Vega (We had one back then) fuel pressure relay with an "On Delay" so it powers the fuel pump for a given
time when the ignition is turned on. I have found references, but nothing with a working part number. That could eliminate the "prime" switch.

I really like the idea of the alternator output as a signal because it exists. It works great for my electric choke.

Fortunately, I have a lot of time before I tear into the coach for the winter re-fit.

Matt
--
Matt & Mary Colie - Chaumière -'73 Glacier 23 - Members GMCMI, GMCGL, GMCES
Electronically Controlled Quiet Engine Cooling Fan with OE Rear Drum Brakes with Applied Control Arms
SE Michigan - Near DTW - Twixt A2 and Detroit
 
The wiring diagram you referenced will work OK but the 10 gauge wire and 30 amp fuse are a little over kill for a pump that draws a little under 2
amps. I have a 3 amp fuse in mine and have never blown it. I would rather blow a fuse if the motor ever locked up than have the pump sit there
getting hot and burning up. Especially Since it has lots of gasoline available to help feed the fire.

Ken B.
--
Ken Burton - N9KB
76 Palm Beach
Hebron, Indiana
 
Matt,

I really hate being a nit-picker, but just to keep everyone straight: That
arrangement of diodes provides OR logic, not AND. In other words, the
circuit is activated when one OR another of the switches is closed.

To provide an AND function, switches merely need to be wired in series.

You knew all that, but some readers may not.

Ken H.

> > Matt,
> >
> > Here's a list of the applications for what I'm in the habit of calling a
> > "Vega Switch":
> > https://1drv.ms/t/s!Ai1vXmS6UF0_gotF3OLJPne3NDCh2w
> >
> > And here is the diagram of my pumps, as I drew it in 2010:
> > https://1drv.ms/b/s!Ai1vXmS6UF0_gotLYbNzGmIJMNYfvA?e=md8n9j
> >
> > Ken H.
>
> Ken,
>
> Your diagram has lots of good ideas that I may borrow. The diode AND gate
> is a great start.
>
> What I have been hoping to locate is the Vega (We had one back then) fuel
> pressure relay with an "On Delay" so it powers the fuel pump for a given
> time when the ignition is turned on. I have found references, but nothing
> with a working part number. That could eliminate the "prime" switch.
>
> I really like the idea of the alternator output as a signal because it
> exists. It works great for my electric choke.
>
> Fortunately, I have a lot of time before I tear into the coach for the
> winter re-fit.
>
> Matt
> --
> Matt & Mary Colie - Chaumière -'73 Glacier 23 - Members GMCMI, GMCGL,
> GMCES
> Electronically Controlled Quiet Engine Cooling Fan with OE Rear Drum
> Brakes with Applied Control Arms
> SE Michigan - Near DTW - Twixt A2 and Detroit
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
>
 
> Matt,
>
> I really hate being a nit-picker, but just to keep everyone straight: That arrangement of diodes provides OR logic, not AND. In other words, the
> circuit is activated when one OR another of the switches is closed.
>
> To provide an AND function, switches merely need to be wired in series.
>
> You knew all that, but some readers may not.
>
> Ken H.

OOps,

Thanks Ken

Matt
--
Matt & Mary Colie - Chaumière -'73 Glacier 23 - Members GMCMI, GMCGL, GMCES
Electronically Controlled Quiet Engine Cooling Fan with OE Rear Drum Brakes with Applied Control Arms
SE Michigan - Near DTW - Twixt A2 and Detroit
 
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