Added dual fuel pumps

[RF_Burns]

Hi all,
I removed the fuel tank selector valve and installed dual fuel pumps. The wire that operated the valve now operated a relay to switch power to the
desired fuel pump. The fuel pumps have a built-in check valve so the fuel does not flow back through the other pump.

Tested and all seems to work as designed!

One thing I will change is the power wire to the fuel pumps. I have a Howell EFI wiring harness. The power wires are only #18 and I have lots of #14
wire. I'll check the voltage drop across the existing wires just for fun.

Here is a couple of pics.
http://www.gmcmhphotos.com/photos/g7210-dual-fuel-pumps.html

Here is a PDF on the importance of proper fuel pump voltage:
http://www.gmcmhphotos.com/photos/dual-fuel-pumps/p66136-the-importance-of-proper-fuel-pump-voltage-tsb.html

I know the brass T is hitting the hole in the frame. I'll put a section of rubber hose on it to prevent rubbing.

--
Bruce Hislop
ON Canada
77PB, 455 Dick P. rebuilt, DynamicEFI EBL EFI & ESC.1 ton front end
http://www.gmcmhphotos.com/photos/showphoto.php?photo=29001
My Staff says I never listen to them, or something like that

 

[LQQKatJon]

Thanks Bruce,

this is in my near future. I am waiting for it to warm up just a little more. I have some hopes and dreams of having them outside the frame rail
for easier service/checking, and fabricate up a guard that doubles as some more sound protection, but I have a feeling once I get the coach jacked
up and get looking under the coach, I will end up with something very similar to your setup.

--
Jon Roche
75 palm beach
St. Cloud, MN
http://lqqkatjon.blogspot.com/

 

[dave stragand1]

Bob and Bruce,

Do either of you have a wiring diagram showing your wiring from the
existing selector switch, the EFI fuel pump relay power feed, and the
relay(s) at the pumps? That would be very helpful for me & others.

Thanks,

-Dave
1978 Transmode near Pittsburgh

-----Original Message-----
From: Gmclist [mailto:gmclist-bounces] On Behalf Of
Bruce Hislop via Gmclist
Sent: Thursday, March 28, 2019 10:26 AM
To: gmclist
Cc: Bruce Hislop
Subject: [GMCnet] Added dual fuel pumps

Hi all,
I removed the fuel tank selector valve and installed dual fuel pumps.
The wire that operated the valve now operated a relay to switch power to
the
desired fuel pump. The fuel pumps have a built-in check valve so the
fuel does not flow back through the other pump.

Tested and all seems to work as designed!

One thing I will change is the power wire to the fuel pumps. I have a
Howell EFI wiring harness. The power wires are only #18 and I have lots
of #14
wire. I'll check the voltage drop across the existing wires just for
fun.

Here is a couple of pics.
http://www.gmcmhphotos.com/photos/g7210-dual-fuel-pumps.html

Here is a PDF on the importance of proper fuel pump voltage:
http://www.gmcmhphotos.com/photos/dual-fuel-pumps/p66136-the-importance-
of-proper-fuel-pump-voltage-tsb.html

I know the brass T is hitting the hole in the frame. I'll put a section
of rubber hose on it to prevent rubbing.

--
Bruce Hislop
ON Canada
77PB, 455 Dick P. rebuilt, DynamicEFI EBL EFI & ESC.1 ton front end
http://www.gmcmhphotos.com/photos/showphoto.php?photo=29001
My Staff says I never listen to them, or something like that

_______________________________________________
GMCnet mailing list
Unsubscribe or Change List Options:
http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org

 

[RF_Burns]

Jon,
I elected to keep my pumps and hoses within the frame for protection in case of an accident. They seem too vulnerable to damage on the outside of the
frame... just me being cautious.

Dave, here is a link to Ken Henderson's wiring diagram for dual fuel pumps. Note that this is for carb applications so he has a prime switch and a
oil pressure switch to shut down the pump in case of an accident. I have fuel injection so the pump is controlled by the EFI computer. I just have
the single relay selecting the fuel pump.

http://www.gmcmhphotos.com/photos/data/5494/Dual_Fuel_Pump_Wiring.pdf

--
Bruce Hislop
ON Canada
77PB, 455 Dick P. rebuilt, DynamicEFI EBL EFI & ESC.1 ton front end
http://www.gmcmhphotos.com/photos/showphoto.php?photo=29001
My Staff says I never listen to them, or something like that

 

[johnny]

I've an MSD Atomic going back on my new engine... but I didn't care for its performance at all on the now dead motor. I attributed the problems to
the engine itself, in that certainly all their users don't get this result. I shall counsel with them.

--johnny
--
Foolish Carriage, 76 26' Eleganza(?) with beaucoup mods and add - ons.
Braselton, Ga.
"I forgive them all, save those who hurt the dogs. They must answer to me in hell" - ol Andy, paraphrased