81 K10 fuse panel layout

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AuroraGirl

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400(?), 350
crank no start while you wait sounds like ignition components or fuel system.
Id open up the distributor cap and see what your module looks like, if its OEM , basically, and id also ohm your coil

Id also ask for a picture of your carb and the fuel line and the fuel pump
 

RiverRat4

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north coast ohio
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r0d
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1981
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k10
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vortec LS-2 5.3L
Hey folks, its been a few since I last posted regarding my issue on crank no start and a seperate issue of parasitic current draw killing my battery if the truck sets for 2 days.

Today I want to focus on the crank no start issue and what headway I have finally honed in on. I/We were immediately focused on electrical issues thinking there was a possible intermittant wire failure or ignition going bad. I went that way because in the beginning of this issue, I began wiggling wires under the dash around the fuse panel with my foot (gently of course) but I did inadvertenty unplug the green blue #10 Ga. wires at a molex connection right by the steering column. I reconnected it and traced it outside through the firewall and I "think" it goes to the transmission? any input on that would be appreciated. However, I began thinking fuel issues and when in a crank no start situation, I would go under the hood and depress the fuel rail schrader valve till it stopped spraying fuel, then the truck will start immediately without issue and run like a champ. So now I am thinking I have a faulty Fuel Pressure sensor, or possibly a breakdown in the fuel vapor reclamation system which I am uncertain is even connected at all since there is no cannister under the hood anywhere. There is a new fuel tank installed and I had to have the tank internal fuel pump re-installed because the original installation messed up the O ring and it had to be reseated. In line with that internal pump, there is a secondary fuel pump along the frame as the line heads to the engine. Any suggestions on where I should start? I am thinking on adding a take off at the scrader valve on the rail and route it to a T valve where one side is the Oil pressure mechanical guage. The oil pressure guage's range in from 0-120 so switching to the fuel side would accurately read fuel pressure which should in in a range around 40-65 psi? At least that will assure me I have good fuel pressure and not low or high fuel pressure since bleeding off the fuel pressure now allows the truck to start without fail.
 

AuroraGirl

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Joined
Sep 8, 2019
Posts
10,172
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Location
Northern Wisconsin
First Name
Taylor
Truck Year
1978, 1980
Truck Model
K10, K25
Engine Size
400(?), 350
Hey folks, its been a few since I last posted regarding my issue on crank no start and a seperate issue of parasitic current draw killing my battery if the truck sets for 2 days.

Today I want to focus on the crank no start issue and what headway I have finally honed in on. I/We were immediately focused on electrical issues thinking there was a possible intermittant wire failure or ignition going bad. I went that way because in the beginning of this issue, I began wiggling wires under the dash around the fuse panel with my foot (gently of course) but I did inadvertenty unplug the green blue #10 Ga. wires at a molex connection right by the steering column. I reconnected it and traced it outside through the firewall and I "think" it goes to the transmission? any input on that would be appreciated. However, I began thinking fuel issues and when in a crank no start situation, I would go under the hood and depress the fuel rail schrader valve till it stopped spraying fuel, then the truck will start immediately without issue and run like a champ. So now I am thinking I have a faulty Fuel Pressure sensor, or possibly a breakdown in the fuel vapor reclamation system which I am uncertain is even connected at all since there is no cannister under the hood anywhere. There is a new fuel tank installed and I had to have the tank internal fuel pump re-installed because the original installation messed up the O ring and it had to be reseated. In line with that internal pump, there is a secondary fuel pump along the frame as the line heads to the engine. Any suggestions on where I should start? I am thinking on adding a take off at the scrader valve on the rail and route it to a T valve where one side is the Oil pressure mechanical guage. The oil pressure guage's range in from 0-120 so switching to the fuel side would accurately read fuel pressure which should in in a range around 40-65 psi? At least that will assure me I have good fuel pressure and not low or high fuel pressure since bleeding off the fuel pressure now allows the truck to start without fail.
DO NOT USE OIL PRESSURE GAUGE FOR FUEL PRESSURE.

You need a fuel pressure gauge!

Also, crawl under the truck and look at the pipes coming off the fuel tank, there should be 3 hoses. if you only see 2, then there may be a thing on the tank vent blocking the line, which would be problematic for fuel, undoing the fuel cap would fix this tempoprarily.
Fuel pressure sensor only job is to reduce fuel pressure with vacuum. So unhook and block it to eliminate the possibility, the engine will run rich but it will idle
 

RiverRat4

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north coast ohio
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r0d
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1981
Truck Model
k10
Engine Size
vortec LS-2 5.3L
Thank you for your fast and explicit direction. I will examine the truck and report back. It is away for the week but I will get it back next friday. I will pass along the info regarding loosing the fuel cap instead of popping the hood and depressing the schrader valve to relieve pressure. I hope that works as well as the valve, its surely much more convenient.

Thank you again and I will report back
 

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