Up hill hesitation

W

wardhillarch

New member
May 23, 2019
59
0
0
I'm getting a hesitation /stall situation when going up steep hills. Unfortunately I live up one. I,ve replaced the carb filter and checked vacuum
line connections.. today I,ll give the whole thing a sea foam treatment hopefully that will help. Hoping to get to the nor'easter chapter rally in
Vermont this weekend. Its a 2 1/2 hour trip any tips to check would be most appreciated
Thank,
Jeff
--
Jeffrey Fleming
1976 edgemonte
Living in Maine
 
Full tank of gas.

--
1977 Kingsley 455 as stock as it gets except lots of Ragusa parts
 
Sea Foam might help, but check your ignition timing and make sure your
distributor Mechanical advance is free.
Have you replaced your fuel lines?

On Wed, Aug 14, 2019 at 6:18 AM Mike Hamm via Gmclist <

> Full tank of gas.
>
> --
> 1977 Kingsley 455 as stock as it gets except lots of Ragusa parts
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>
--
Jim Kanomata
Applied/GMC, Newark,CA
jimk
http://www.appliedgmc.com
1-800-752-7502
 
Sir: possibly the pickup socks in the tanks are clogged up. Maybe try switching tanks. I have had some success removing gas cap and blowing shop
air back thru the rubber hose coming out of the switching valve then switching the valve and doing the other tank pick up.

> I'm getting a hesitation /stall situation when going up steep hills. Unfortunately I live up one. I,ve replaced the carb filter and checked vacuum
> line connections.. today I,ll give the whole thing a sea foam treatment hopefully that will help. Hoping to get to the nor'easter chapter rally in
> Vermont this weekend. Its a 2 1/2 hour trip any tips to check would be most appreciated
> Thank,
> Jeff

--
C. Boyd
76 Crestmont
East Tennessee
 
I have not replaced my fuel lines only had the coach since June hoping to get it looked over by mike at New England rv but something always comes up
where I can't make my appointment. Had no problems driving this from Wisconsin to maine although I do remember experiencing some hesitation coming out
of Detroit but that was a one time thing. This seems to occur only under load. Idles great
--
Jeffrey Fleming
1976 edgemonte
Living in Maine
 
Idles great, only stagger was under load? Look tofuel lines and filters. If the lines arebn't barrier hose, drop the tanks and replace ALL the
rubber. This is one that isn't particularly hard, but it is time consuming. Do it yourself for a hundred or less in hoses and a couple of ratchet
straps. Hire it done and you're going to buy several hours of labor at a hundred an hour more or less. Let your pocket be your guide.

--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
 
What Johnny said...lines are probably soft, collapsing under high fuel flow. And Chuck is probably right about the filter socks being partially
clogged causing more suction on the hoses than normal that will definitely collapse weakened hose.
--
Terry Kelpien

ASE Master Technician

73 Glacier 260

Smithfield, Va.
 
Fuel hoses could also be cracked and sucking air. This fuel starvation is a common problem with this fuel system. It's not truly "vapor Lock" but
similar as the gas vaporizes in the lines and the carburetor runs out of gas. An electric fuel pump near the tanks usually clears it up.

I fought this for years and finally remedied it by moving my fuel hoses to the outside of the frame and added a carter 4070 fuel pump, along with a
cartridge filter, on my aux tank. Even on my last two mid Summer trips (in Arizona heat) I didn't have a problem.
--
Carl Stouffer
'75 ex Palm Beach
Tucson, AZ.
Chuck Aulgur Reaction Arm Disc Brakes, Quadrabags, 3.70 LSD final drive, Lenzi knuckles/hubs, Dodge Truck 16" X 8" front wheels, Rear American Eagles,
Solar battery charging. GMCSJ and GMCMI member
 
Sure sounds like fuel starvation. If it does it every time you go up that hill then it probably is not vapor lock. If it is only occasionally, then
do not rule out the vapor lock problem.

Since the coach is new to you look for an added fuel filter somewhere. Usually POs install then in the rubber line on the input to the fuel pump, or
by the selector valve, or in the pick up lines to both tanks.

Also could be a weak fuel pump. If it doubt, replace it. They are cheap.
--
Ken Burton - N9KB
76 Palm Beach
Hebron, Indiana
 
I get about two calls a day on fuel issue.
They ALL have not replaced the fuel lines, tank selector valve, vapor
separator and mechanical pump.
They ALL have Old rubber, so they need to be replaced.

On Wed, Aug 14, 2019 at 9:42 AM Ken Burton via Gmclist <

> Sure sounds like fuel starvation. If it does it every time you go up that
> hill then it probably is not vapor lock. If it is only occasionally, then
> do not rule out the vapor lock problem.
>
> Since the coach is new to you look for an added fuel filter somewhere.
> Usually POs install then in the rubber line on the input to the fuel pump,
> or
> by the selector valve, or in the pick up lines to both tanks.
>
> Also could be a weak fuel pump. If it doubt, replace it. They are
> cheap.
> --
> Ken Burton - N9KB
> 76 Palm Beach
> Hebron, Indiana
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>

--
Jim Kanomata
Applied/GMC, Newark,CA
jimk
http://www.appliedgmc.com
1-800-752-7502
 
> I'm getting a hesitation /stall situation when going up steep hills. […] This seems to occur only under load. Idles great

I completely agree with what everyone else has said regarding fuel delivery and the importance of good hoses and filtering.

I will, however, also point out that these same exact symptoms can occur if there are one or more things in the ignition system that are spongy. As fuel mixture and cylinder pressures increase during steep hill climbs and other high load events (like aggressive acceleration) the dielectric characteristic of the fuel/air mix in the cylinders will change and higher voltages are necessary to ionize the gap between the spark plug electrodes. If something is compromised in the ignition system such as a tired coil, dirty rotor or cap contacts or even wires that have developed high resistance then strong sparks may not reliably occur on every power stroke during the conditions described.

It would be interesting to know if the hesitation and stumbling occurs immediately upon application of increased load (pointing to an ignition problem) versus some non-trivial amount of time after the load is applied which would indicate fuel starvation.

—Jim

Jim Miller
1977 Eleganza
1977 Royale
Hamilton, OH
 
Moving the fuel lines to the outside of the frame rails is fine till you get T boned. Then you have a potential emulation of the Crown Vic/ Pinto rear
ended fire after crash.
--
John Lebetski
Woodstock, IL
77 Eleganza II
 
No the hesitation happens at some point during the ascent. I'll try changing out the fuel filter before redoing all of the lines. Last trip around the
block it made it up the hill. But there was still some hesitation just prior. It was then I noticed the filter spring sitting on top of the block.
Duh! This was after replacing carb filter. All back together correctly now. This engine was supposedly rebuilt 40,000 miles ago . I,ll look to see
if fuel line replacement were mentioned in any of the paper work I have . They don't look 45 years old from what I can see but have yet to find any
markings on them.
Thanks everyone
--
Jeffrey Fleming
1976 edgemonte
Living in Maine
 
It doesn't take long for Ethanol to eat the fuel hose. In 2009 while the engine was being rebuilt, I dropped the tanks and replaced all the line with
30R7 hose which is suppose to be Ethanol rated. By 2014 the supply hose over one tank was sucking air, so the next winter I dropped the tanks and
replaced the rubber hose with steel lines and replaced the what rubber hose there was with 30R9 and 30R14.

The 30R7 hose had become hard, brittle and porous in 5 years!

--
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
 
"I'll try changing out the fuel filter before redoing all of the lines."

If they are older, you're riding for a fall and a chance of setting the woods on fire. Change EVERY rubber hose on the coach which isn't barrier
hose.

--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
 
Jeffery,

I (unfortunately) wrote here about the fuel system twice.
Do a search for "Lifting fuel tanks" because that outlines how to get the tanks up and down (more accurately, down and back up) with a very minimum of
stress and stain.
Also search for "Recommending High T" because this is a cure for one of the causes of fueling problems.

Or, if you choose, send me a PM with a @ddress and I will return with both as flat email text as part of the response.

Matt - Who had his tanks down fixing problems one at a time.

--
Matt & Mary Colie - '73 Glacier 23 - Members GMCMI, GMCGL, GMCES
Electronically Controlled Quiet Engine Cooling Fan
OE Rear Drum Brakes with Applied Control Arms
SE Michigan - Twixt A2 and Detroit
 
Guess it should be done regardless. Who sells the correct hose? Is there a diy write up someplace on this topic?
Thanks
--
Jeffrey Fleming
1976 edgemonte
Living in Maine
 
the next time I change my fuel lines, because mine are now 10 years old, I will be using nylon and push lock connects.
This will solve 2 problems:

1. it's a ton easier to use than steel lines, bending is a non issue
2. It will eliminate all rubber connections between the steel lines however short
3. It makes it easy to remove and replace the tanks

________________________________
From: Gmclist on behalf of Johnny Bridges via Gmclist
Sent: Thursday, August 15, 2019 8:18 AM
To: gmclist
Cc: Johnny Bridges
Subject: Re: [GMCnet] Up hill hesitation

"I'll try changing out the fuel filter before redoing all of the lines."

If they are older, you're riding for a fall and a chance of setting the woods on fire. Change EVERY rubber hose on the coach which isn't barrier
hose.

--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

_______________________________________________
GMCnet mailing list
Unsubscribe or Change List Options:
http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
 
If you really want bulletproof fuel lines, the best is metal. Properly
bent, secured, and flared. Use DOT approved fittings, of coarse.
Next is braided covered fuel lines that are Alcohol Resistant, AN
fittings and exacting workmanship. Secure them properly, protect them from
heat and collision damage.
Next would be Gates "Barricade" fuel hoses. Use full circle fuel
injection hose clamps. There again, protect it from heat and collision
damage. Check this every spring, and replace it at the first sight of any
age related issues.
Never, never, never any rubber hose between the mechanical fuel pump and
carb. No in-line filters here either, that is what the carb filter is for.
Jim Hupy
Salem, Or

On Thu, Aug 15, 2019, 11:19 AM Keith V via Gmclist
wrote:

> the next time I change my fuel lines, because mine are now 10 years old, I
> will be using nylon and push lock connects.
> This will solve 2 problems:
>
> 1. it's a ton easier to use than steel lines, bending is a non issue
> 2. It will eliminate all rubber connections between the steel lines
> however short
> 3. It makes it easy to remove and replace the tanks
>
> ________________________________
> From: Gmclist on behalf of Johnny
> Bridges via Gmclist
> Sent: Thursday, August 15, 2019 8:18 AM
> To: gmclist
> Cc: Johnny Bridges
> Subject: Re: [GMCnet] Up hill hesitation
>
> "I'll try changing out the fuel filter before redoing all of the lines."
>
> If they are older, you're riding for a fall and a chance of setting the
> woods on fire. Change EVERY rubber hose on the coach which isn't barrier
> hose.
>
> --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
>
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>
 
You must log in or register to reply here.
GMCMI Fall 2026 Rally
Applied GMC

Share this page

Share this page
Top Bottom
Back