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My question would be is were is the trash be coming from? Are you measuring the low pressure with a mechanical gauge and where are you checking it.
 

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Discussion Starter · #22 ·
My question would be is were is the trash be coming from? Are you measuring the low pressure with a mechanical gauge and where are you checking it.
Trash is maybe not the right word. There was some white lithium grease floating in there from the first time I replaced that filter. Cleaned it all out, “primed” with no filter and paper towels to make sure none of the grease had backflowed toward the lift pump, and put a new filter in with a tiny coat of aviation o ring lube (Parker o lube, good stuff) I had around. I am watching the fuel pressure via a scanner, fuel feed pressure signal.
 

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Discussion Starter · #23 ·
Image 9f0... is the high pressure real vs high pressure command. The second down is real, third down is command.
 

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Because you have a low pressure fault code stored that will cause an issue on the high pressure side. So you need to determine the source of that code first. In order to do that you really need to use a manual gauge to monitor the pressure to verify whether or not the fuel pressure is dropping off or the sensor is not reading correctly.
 

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Discussion Starter · #25 ·
No fuel gauge yet. However, this thing stalled decelerating down hill with no load whatsoever yesterday. Completely different from the previous requirements for failure. And the lift pump was screaming, the longest restart I have dealt with yet. Today it failed (I disconnected egr this morning for s***’s and giggles but no difference). When I removed the fuel tank cap out of curiosity on the side of the road it hissed something awful at me. Could it be this tank is going into vacuum and I (we) have been chasing my tail over a faulty tank cap not venting properly?!? 🤦🏽 Testing to commence, cap ordered for the fact it is cheap.
 

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No fuel gauge yet. However, this thing stalled decelerating down hill with no load whatsoever yesterday. Completely different from the previous requirements for failure. And the lift pump was screaming, the longest restart I have dealt with yet. Today it failed (I disconnected egr this morning for s***’s and giggles but no difference). When I removed the fuel tank cap out of curiosity on the side of the road it hissed something awful at me. Could it be this tank is going into vacuum and I (we) have been chasing my tail over a faulty tank cap not venting properly?!? Testing to commence, cap ordered for the fact it is cheap.
Tank going in to vacuum would certainly be a plausible explanation for the symptoms. More fuel it demanded the more vacuum it would develop even if it wasn't completely tight and after shutting down or a short break enough air would seep back in to allow it to run again. In fact, a higher flow lift pump would be more likely to manifest the problem. There most certainly should NOT be the sound of a vacuum release when you take off the gas cap.

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Discussion Starter · #27 ·
Towed around 250miles today with ZERO issues whatsoever. Fuel tank not venting properly seems to have been the cause. Took the tank down to 40-ish miles thinking maybe I cut the straw too short when installing the fass but not a hiccup.
46419
 
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