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Fuel Solenoid [message #225792]

Tue, 15 October 2013 19:46

mickey szilagyi

Messages: 273
Registered: January 2013

Karma: 0

Senior Member

I noticed in the chassis wiring schematic the fuel solenoid and was wondering how it worked as far as switching from tank to tank. It appears it has a default position or for the lack of a better term a resting position. Does it stay in the main tank position when off? And when power is applied does it switch to the auxiliary tank? If that's the case does applying that constant power over a long period of time harm it in any way? Is it better for the solenoid to be switched to one tank over the other to prolong it's life? And if it's switched to one tank by applying power to it does it automatically switch back when the ignition is turned off.

I hope I'm asking the right questions or at least you get the idea of what I'm trying to determine.

Thanks as always.

Mickey 1977 Kingsley, 403, Lansing, MI

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Re: Fuel Solenoid [message #225793 is a reply to message #225792]

Tue, 15 October 2013 20:14

zhagrieb

Messages: 676
Registered: August 2009
Location: Portland Oregon

Karma: 0

Senior Member

You're right on. It passes fuel from the main tank when "off", from the aux when "on". Will most likely work for years when "on".

Glenn

Glenn Giere, Portland OR, K7GAG '73 "Moby the Motorhome" 26'

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Re: Fuel Solenoid [message #225794 is a reply to message #225792]

Tue, 15 October 2013 20:18

JohnL455

Messages: 4447
Registered: October 2006
Location: Woodstock, IL

Karma: 12

Senior Member

No juice... Main.
Juice applied... Aux. you have it correct
I'd think it's continuous duty rated for when in Aux, but this position was intended so as to be used as a strand prevention feature.

John Lebetski
Woodstock, IL
77 Eleganza II

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Re: Fuel Solenoid [message #225799 is a reply to message #225792]

Tue, 15 October 2013 20:46

mickey szilagyi

Messages: 273
Registered: January 2013

Karma: 0

Senior Member

Thank you. Has anyone had or heard of a fuel solenoid failure? The auxiliary tank and the gas in it won't do much good if the solenoid is or goes bad. There probably isn't anyway of knowing it's bad until you need the auxiliary gas and can't get it. You'd have to get to it and test it some how.

Thanks again,

Mickey 1977 Kingsley, 403, Lansing, MI

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Re: [GMCnet] Fuel Solenoid [message #225802 is a reply to message #225799]

Tue, 15 October 2013 20:57

Ken Henderson

Messages: 8726
Registered: March 2004
Location: Americus, GA

Karma: 9

Senior Member

Mickey,

Yes, there have been many failures of the solenoid valves. Failure to
switch at all, and failure "in transit" -- half way between positions so
that no fuel can be drawn. Ethanol seems to be expediting the failures.

My own solution to the possibility of valve failure was to eliminate it.
The tank selector switch now selects one of two Carter 4070 electric
pumps, one for each tank. The cost is not much more than the replacement
cost of the valve. The redundancy is certainly worth that small extra cost.

Ken H.
Americus, GA
'76 X-Birchaven w/Cad500/Howell EFI & EBL
www.gmcwipersetc.com

On Tue, Oct 15, 2013 at 9:46 PM, Mickey Szilagyi
<mickey@apex-internet.com>wrote:

>
>
> Thank you. Has anyone had or heard of a fuel solenoid failure? The
> auxiliary tank and the gas in it won't do much good if the solenoid is or
> goes bad. There probably isn't anyway of knowing it's bad until you need
> the auxiliary gas and can't get it. You'd have to get to it and test it
> some how.
>
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Ken Henderson
Americus, GA
www.gmcwipersetc.com
Large Wiring Diagrams
76 X-Birchaven
76 X-Palm Beach

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Re: [GMCnet] Fuel Solenoid [message #225803 is a reply to message #225799]

Tue, 15 October 2013 20:58

emerystora

Messages: 4442
Registered: January 2004

Karma: 13

Senior Member

Yes, they go bad. It is especially bad when they stick half open. Then they can pull air from an empty tank and you are really stuck.
If they don't switch tanks at least you can drive on the one tank and keep it full by filling more frequently until you replace the valve.

Emery Stora

On Oct 15, 2013, at 7:46 PM, Mickey Szilagyi wrote:

>
>
> Thank you. Has anyone had or heard of a fuel solenoid failure? The auxiliary tank and the gas in it won't do much good if the solenoid is or goes bad. There probably isn't anyway of knowing it's bad until you need the auxiliary gas and can't get it. You'd have to get to it and test it some how.
>
> Thanks again,
> --
> Mickey
> 1977 Kingsley, 403, Lansing, MI
> _______________________________________________
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> Unsubscribe or Change List Options:
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Re: [GMCnet] Fuel Solenoid [message #225814 is a reply to message #225802]

Wed, 16 October 2013 06:26

mickey szilagyi

Messages: 273
Registered: January 2013

Karma: 0

Senior Member

Ken and others,

Are the electric fuel pumps in the tanks or exterior so they are easy to install and get to? If not in the tanks where did you put them? Side by side up in the engine compartment or back perhaps where the current fuel solenoid is now on our coach? Does the manual fuel pump on the engine stay put as well with the electric pumps?

I believe all this info has already been discussed on the forum as I recall reading about fuel pumps in the past. The solenoid was my biggest concern, sorry.

Can't beat this forum, thanks everyone.

Mickey 1977 Kingsley, 403, Lansing, MI

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Re: Fuel Solenoid [message #225816 is a reply to message #225799]

Wed, 16 October 2013 08:07

Matt Colie

Messages: 8547
Registered: March 2007
Location: S.E. Michigan

Karma: 7

Senior Member

mickey szilagyi wrote on Tue, 15 October 2013 21:46

Mickey,

I didn't answer last night because I quit the keyboard about 9 (21) most nights.

Those valves are a regular failure point. I have only had two samples in my data, but they seem to fail most often by not shutting both inlets. This means it may not leave you unable to get fuel from the auxiliary tank, but it does mean that if you wait until the main feed stumbles or even gets the "Low Fuel" light that you may not have the reserve you are expecting.

A test is simple. With all three lines off (fuel will siphon out if given a chance), use a short piece of fuel line (no clamp needed) to blow into both inlet ports. If you can't hold pressure on the Auxiliary port, it's toast. You don't really have to test the main (requires supplying power), but it wouldn't be a stupid thing to do while Chris is under there.

I have replaced mine with the commonly available part. There seems to be only one and it is upside down as backwards from what we have. It really doesn't want to fit between the fill pipe and the frame, but with the addition of a ground lead, it can be screwed the wood of the coach floor.

While I really like Emery's plan with the pumps in the tanks, but it is not a simple mod and would require dropping the tanks (again - says the guy that has had his down four times). (Neither was all metal, but I did that one.) Two pumps, two filters, two check valves and a T has a lot of charm. With the pumps low and close to the tank, it should reduce the chance of vapor lock and give you a comforting redundancy.

I still want to find out how you get to 28 ohms with the tank near full.

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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Re: [GMCnet] Fuel Solenoid [message #225818 is a reply to message #225799]

Wed, 16 October 2013 08:57

USAussie

Messages: 15912
Registered: July 2007
Location: Sydney, Australia

Karma: 6

Senior Member

Mickey,

Three years ago as Helen and I were about to leave John Sharpe's home for our yearly tour when all the gages in Double Trouble died;
no gas, no oil pressure, no water temp indications. We discovered that the TELL TALE fuse (IIRC) had blown. When we replaced it the
instruments came back. Hooray! As I let the engine warm up a bit - bang - they died again. Yep fuse again. We had a quick look at
the wiring diagram and decided that the circuitry was too complicated to try and trouble shoot it in the dark so we went o an
AutoZone and bought a mechanical oil pressure gage and plumbed it in. I decided I could live without the rest as Double Trouble had
never overheated and I could just stop every couple hundred miles and fill up.

We made the trip without incidence and when I got to the COOP we did some more troubleshooting and found the selector valve solenoid
burned out. We replaced it and JimB installed one of his little 1-4 psi Facet fuel pumps that comes on when you switch to AUX to
pressurize the line to the mechanical fuel pump. That's when we discovered the root cause of the problem. Believe it or not the MAIN
/ AUX switch in Double Trouble was installed UP side DOWN. When it is in MAIN it is actually in AUX and vice versa; therefore most
of the time the selector valve was powered. It was the original selector valve so it appeared the switch was installed at the
factory that way. I thought I could fix it by turning the connector on the switch over but you can't do that it only goes on one
way. To fix it you have to remove the wood grain fascia plate and turn the whole switch over. I took the easy way out and put some
Dymo labels over the OEM labels. I'm going to make a new dash and use toggle switches for the MAIN / AUX and BAT NORMAL / BAT BOOST
switches.

Regards,
Rob M.
USAussie - Downunder
AUS '75 Avion - The Blue Streak TZE365V100428
USA '75 Avion - Double Trouble TZE365V100426

-----Original Message-----
From: Mickey Szilagyi

Thank you. Has anyone had or heard of a fuel solenoid failure? The auxiliary tank and the gas in it won't do much good if the
solenoid is or goes bad. There probably isn't anyway of knowing it's bad until you need the auxiliary gas and can't get it. You'd
have to get to it and test it some how.

Thanks again,
--
Mickey

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Regards, Rob M. (USAussie) The Pedantic Mechanic Sydney, Australia '75 Avion - AUS - The Blue Streak TZE365V100428 '75 Avion - USA - Double Trouble TZE365V100426

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Re: [GMCnet] Fuel Solenoid [message #225825 is a reply to message #225818]

Wed, 16 October 2013 10:38

jim kanomata

Messages: 257
Registered: March 2007
Location: fremont,ca

Karma: 12

Senior Member

For those that are going to use the High pressure pump for Fuel injection, that valve rated for only 7 psi, so a one for EFI units should not use.

Jim Kanomata Applied/GMC, Fremont,CA jimk@appliedairfilters.com http://www.appliedgmc.com 1-800-752-7502

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Re: [GMCnet] Fuel Solenoid [message #225826 is a reply to message #225814]

Wed, 16 October 2013 10:37

sgltrac

Messages: 2797
Registered: April 2011

Karma: 1

Senior Member

Ken h has his on the outside o the drivers frame rail. The pump on The Pig is on the xmember forward of the tanks as is the in line fuel filter. There has been much talk of installing outside the frame rail for ease of access or inside for safety/ protection of the fuel system. Since I throw a jack under the bogie whichever side I'm working anyway the access point is moot. I prefer all fuel/electrical inside the frame rails. I had my pump off in the Dalles on my way home from Coos bay when I pulled the filter and it took me no more time than Ken H to pull his in front of my shop.

Todd Sullivan

Sully
77 royale
Seattle

Sully
77 royale
Seattle

> On Oct 16, 2013, at 4:26 AM, Mickey Szilagyi <mickey@apex-internet.com> wrote:
>
>
>
> Ken and others,
>
> Are the electric fuel pumps in the tanks or exterior so they are easy to install and get to? If not in the tanks where did you put them? Side by side up in the engine compartment or back perhaps where the current fuel solenoid is now on our coach? Does the manual fuel pump on the engine stay put as well with the electric pumps?
>
> I believe all this info has already been discussed on the forum as I recall reading about fuel pumps in the past. The solenoid was my biggest concern, sorry.
>
> Can't beat this forum, thanks everyone.
> --
> Mickey
> 1977 Kingsley, 403, Lansing, MI
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
_______________________________________________
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Unsubscribe or Change List Options:
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Sully 77 Royale basket case. Future motorhome land speed record holder(bucket list) Seattle, Wa.

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