Author Topic: 1976 K10 stalling at altitude  (Read 560 times)

Offline Ddebroux

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1976 K10 stalling at altitude
« on: November 20, 2020, 02:43:50 PM »
Hello.  When I drive up from the front range (5400 ft) in Colorado to my house at 8400 ft the truck has consistently stalled in the same spot 4 times.  It has a new fuel pump, sending unit and the tank has been cleaned so don’t think it’s a fuel issue. I did notice the evap canister is missing and the second hose from the sending unit runs up near the stock fuel pump and terminates.  Could this be part of the problem? 

Offline VileZambonie

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Re: 1976 K10 stalling at altitude
« Reply #1 on: November 20, 2020, 08:11:45 PM »
Stalls.... idling? Accelerating? Decelerating? More detail
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Offline Ddebroux

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Re: 1976 K10 stalling at altitude
« Reply #2 on: November 23, 2020, 10:04:16 AM »
Thanks for responding.  It stalls when I am accelerating up a hill.  For context I drive up a steep hill for about 20 minutes then downhill and flat for about 5 minutes. When I start to go up hill again it wants to stall about 30 seconds up.  It tends to stall more if I have a load something heavy in the box but it also stalls on an empty load.  If I let it cool for about 20 minutes it will start right up again.

Offline VileZambonie

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Re: 1976 K10 stalling at altitude
« Reply #3 on: November 23, 2020, 06:03:09 PM »
Loosen your gas cap and see if it still does it.
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Offline JohnnyPopper

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Re: 1976 K10 stalling at altitude
« Reply #4 on: November 23, 2020, 08:40:14 PM »
At that altitude it probably cools pretty fast... 8)

VZ do you think the cap is not 'breathing'? Is there a one way valve of sorts? Sounds logical...
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Offline Mike81K10

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Re: 1976 K10 stalling at altitude
« Reply #5 on: November 23, 2020, 10:34:48 PM »
My truck is a Colorado Truck. I use to have the same problem and had to change my carb jets (different size) to fix to problem and then afterwards the shop that changed the jets did some carb adjustments. You may not have the same problem/solution as I had.

Offline Ddebroux

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Re: 1976 K10 stalling at altitude
« Reply #6 on: November 24, 2020, 11:57:05 PM »
I loosened the gas cap today and it didn’t stall!  I ordered a vented gas cap today which will hopefully fix the problem.  Thanks for the advice.  If this doesn’t fix it permanently I’ll look into adjusting the carb jets. Any chance you can share the name of the shop it took it too Mike?