95 c1500 4.3 TBI has fuel and spark, cranks, no start

[thinger2]

I think I'm getting closer - question, try new cap and rotor or whole new distributor? It is still technically sending spark...

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Damn that cap is crusty crispy fried and so are the plugs and rotor.
I bet the plug wires are also bad.
Do a normal plug cap rotor wire tune up
Set the timing to 0 tdc
clean the battery cables and put a new fuel filter in.
Those parts are smoked.

 

[unpredictable1]

Damn that cap is crusty crispy fried and so are the plugs and rotor.
I bet the plug wires are also bad.
Do a normal plug cap rotor wire tune up
Set the timing to 0 tdc
clean the battery cables and put a new fuel filter in.
Those parts are smoked.

Yup - in a later post I mentioned I already changed all that and she fired up, they definitely made a difference. Seems to be a remaining fuel issue right now from what I can tell so far.

 

[thinger2]

Yup - in a later post I mentioned I already changed all that and she fired up, they definitely made a difference. Seems to be a remaining fuel issue right now from what I can tell so far.

Did you replace the fuel filter?
You can get a look at what your injectors are doing by hooking up a timing light in the usual way and aiming that light at the injector spray.
After dark is best.
You should see a steady spray pattern.
What you are looking for is drips.
You should not see any drips of fuel while that strobe light is on.
Your injectors have a tiny little filter screen on the side of them.
A plastic piece with a wire screen smaller in diameter than a pencil eraser.
Pretty common for that to have disintegrated and the crud backs up into the injector body.
So a tbi rebuild might be a good next step.
Trottle shaft bushing is another subject.
The number one mistake that you will see on youtube is using the screws to pull the top plate down.
That top plate is weak pot metal.
When you pull that top plate check it for flatness and look for cracks.
Push it back on with palm of your hand and seat it before you put the screws in.
Otherwise it will often kink and leak gas.

 

[unpredictable1]

Forgive me - not sure what you mean about a top plate?

I did replace the fuel filter, got fuel pressure gauge set up, my pump isn't even priming anymore (stays at 0 psi) and even under hard cranking, stays at 0 psi. Fuse is good - I tested the relay earlier this week and it was good. (the truck was idling after I did some ignition items but really labored with throttle input)

So now I'm wondering if the fuel pump finally gave up the ghost for what little it had left.

 

[Schurkey]

The number one mistake that you will see on youtube is using the screws to pull the top plate down.
That top plate is weak pot metal.
When you pull that top plate check it for flatness and look for cracks.
Push it back on with palm of your hand and seat it before you put the screws in.
Otherwise it will often kink and leak gas.

Forgive me - not sure what you mean about a top plate?

Glass plate for flatness, sandpaper, "top plate".

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Starting out.

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Partway there.

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Progress.

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Good enough. Has been working for a few years, but looking back, I probably should have gone a little more.

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I did replace the fuel filter, got fuel pressure gauge set up,

I'm not a big fan of using a 100 psi max gauge to read a system that spec's at 9--13 psi. A ~30 psi gauge would be nice.

my pump isn't even priming anymore (stays at 0 psi) and even under hard cranking, stays at 0 psi.

Yup. That's a problem no matter what gauge is on the fuel pressure tester.

Verify the power and ground to the pump.

So now I'm wondering if the fuel pump finally gave up the ghost for what little it had left.

You'll know when you check the power and ground, and make sure that the gas tank isn't empty.

 

[unpredictable1]

Glass plate for flatness, sandpaper, "top plate".

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Starting out.

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Partway there.

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Progress.

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Good enough. Has been working for a few years, but looking back, I probably should have gone a little more.

You must be registered for see images attach

I'm not a big fan of using a 100 psi max gauge to read a system that spec's at 9--13 psi. A ~30 psi gauge would be nice.


Yup. That's a problem no matter what gauge is on the fuel pressure tester.

Verify the power and ground to the pump.


You'll know when you check the power and ground, and make sure that the gas tank isn't empty.

Yeah she has about 3/8ths of a tank in her. I reached my hands up around the top of the pump and the ground seems secure and in good shape.

Of course with everything getting packed up with the move there's no test light around but I do have this multimeter below if I can figure out how to use to check power to the pump. I'll look up the pump's hot wire with ignition on - I thought I previously read is was the grey wire in the harness along the frame rail.

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[Schurkey]

Yeah she has about 3/8ths of a tank in her.

OK.

I reached my hands up around the top of the pump and the ground seems secure and in good shape.

Well, you know where it is. But "feeling" it is not a proper test of it's resistance.

I do have this multimeter below if I can figure out how to use to check power to the pump. I'll look up the pump's hot wire with ignition on - I thought I previously read is was the grey wire in the harness along the frame rail.

Three clicks to the left--20 volts DC. AT MINIMUM, check the voltage to the pump WITH THE PUMP RUNNING, or at least potentially running--wires connected, power and ground supplied. You need to check for voltage as close to the pump as practical--probably the rearmost connector before the harness goes up 'n' over the tank. You're looking for as close to battery voltage as practical. Realistically, you're gonna be a volt or two below battery voltage. THEN, verify that there's little or no voltage on the ground wire WITH THE PUMP RUNNING, or at least potentially running--wires connected, power and ground connected. AGAIN, you need to test for voltage as close to the pump as practical. ONE volt might be acceptable, less is better.

 

[unpredictable1]

OK.


Well, you know where it is. But "feeling" it is not a proper test of it's resistance.

Three clicks to the left--20 volts DC. AT MINIMUM, check the voltage to the pump WITH THE PUMP RUNNING, or at least potentially running--wires connected, power and ground supplied. You need to check for voltage as close to the pump as practical--probably the rearmost connector before the harness goes up 'n' over the tank. You're looking for as close to battery voltage as practical. Realistically, you're gonna be a volt or two below battery voltage. THEN, verify that there's little or no voltage on the ground wire WITH THE PUMP RUNNING, or at least potentially running--wires connected, power and ground connected. AGAIN, you need to test for voltage as close to the pump as practical. ONE volt might be acceptable, less is better.

Awesome, thank you. I'll try to check this tomorrow.

 

[unpredictable1]

Did you replace the fuel filter?
You can get a look at what your injectors are doing by hooking up a timing light in the usual way and aiming that light at the injector spray.
After dark is best.
You should see a steady spray pattern.
What you are looking for is drips.
You should not see any drips of fuel while that strobe light is on.
Your injectors have a tiny little filter screen on the side of them.
A plastic piece with a wire screen smaller in diameter than a pencil eraser.
Pretty common for that to have disintegrated and the crud backs up into the injector body.
So a tbi rebuild might be a good next step.
Trottle shaft bushing is another subject.
The number one mistake that you will see on youtube is using the screws to pull the top plate down.
That top plate is weak pot metal.
When you pull that top plate check it for flatness and look for cracks.
Push it back on with palm of your hand and seat it before you put the screws in.
Otherwise it will often kink and leak gas.

That's a neat trick with the timing light on the injector during the night, I don't have a timing light here unfortunately but I will check this top plate in the near future.

 

[unpredictable1]

I have damn near 12 volts to the pump (11.XX), I can even hear it turn on with accessories for a few seconds, PSI still shows 0.