'01 F-150 4.6L, complaining that the truck wouldn't start for three days straight. Felt like starting on the fourth and immediately brought it to us. No start, no fuel pressure.
Scoping the fuel pump current with a fuel pump relay jumper installed so I can field the pump on my own. This is what I find:
I'm pretty sure the pump motor is seizing up. :huh: It's not like the brushes are worn or the motor segments are open - there's current flow every time I close the relay. I sold a pump assembly and time to investigate the tank for water/debris/sugar/whatever.
The spike followed by hash events look like the pump running and the two tall ones do look like locked rotor. It is a bit weird that once the pump gets moving it's current draw is normal.
Any chance of zooming in to see individual commutator humps? I'm wondering if there is a "sticky spot" that has, slightly, higher current on a single, repeating commutator.
"Knowledge is a weapon. Arm yourself, well, before going to do battle."
"Understanding a question is half an answer." I have learned more by being wrong, than I have by being right.
Matt T wrote: It is a bit weird that once the pump gets moving it's current draw is normal.
Agreed. Once it gets moving, it's happy-ish. It even produces some fuel pressure! :silly:
Any chance of zooming in to see individual commutator humps? I'm wondering if there is a "sticky spot" that has, slightly, higher current on a single, repeating commutator.
You know, I actually wondered the same thing? Which is why I went back to these captures in the first place. Turns out, the Triton didn't save the capture correctly. Again.
This was my screenshot:
And this is the exact same capture when viewed in ShopStream Connect:
All the current values are off by one decimal point. :blink: So all of the detail in the pump waveform is gone. If it helps, this is about the most coherent detail I could get out of it:
This is a good place for AC coupling. Who cares what the actual current draw is (we already know). We want to see detail. Set the scope to a low Volts DC setting and turn on AC coupling. This will "filter out" the base current and zoom in on the detail of the current.
"Knowledge is a weapon. Arm yourself, well, before going to do battle."
"Understanding a question is half an answer." I have learned more by being wrong, than I have by being right.
Apparently there is a new version of Shopstream. If you haven't already upgraded that might fix the problem viewing Triton files. I'm installing it right now if you want to post the VSM and I'll try viewing it.
Matt T wrote: Apparently there is a new version of Shopstream. If you haven't already upgraded that might fix the problem viewing Triton files. I'm installing it right now if you want to post the VSM and I'll try viewing it.
And ever since the update to 20.4, the scope file formats are now .LSM.
