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Old 02-05-2019, 06:12 AM
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DmaxMaverick DmaxMaverick is offline
Join Date: Apr 2001
Location: CA
Posts: 12,568

Welcome aboard!

I think you're on the right track, chasing the bubbles. If it runs and dies after priming, and runs longer when you pump the primer, it's likely you've identified a problem. A couple simple things come to mind: fuel filler cap and fuel filter. Wild temperature swings will exaggerate fuel expansion and contraction in the system, and will exploit any weakness.

The Diesel fuel filler cap vents in both directions, and they fail over time. They are cheap, and should be replaced early in the diagnostic process. A failed cap vent can cause loss of prime as the fuel system volume contracts, usually during an overnight sit, and is exaggerated as the temperature drops from operating to very cold. You can leave it loose to mitigate any effects in the meanwhile.

The fuel filter may have lost it's seal, and is usually easily restored by a removal and reinstall (often just a loosen-tighten). If you're using the plastic can model filter, all bets are off. Good luck with that one. I suggest replacing it with the steel can model, at least during this process. In most cases, the plastic filter does not cause issues, but can be problematic with some. Just a bad idea that adds potential point of failure, IMO.

Adding a fuel lift pump and controller system will do 2 things. One is, it will absolutely prevent air intrusion while it's running. The other is, it will help identify fuel system leaks between the lift pump and engine-driven high pressure pump. While it is recommended, the OEM system should not prevent running though, in any case, if the system is otherwise healthy.

Do this to identify air intrusion (even if you've already done it):
Open the fuel filter bleed screw on top of the fuel filter assy, and pump the primer until fuel is present. Close the bleeder screw. Pump the primer until you can't. This will push fuel through the high pressure pump. It may take 30-50+ pump cycles, so just keep going until it's very hard to push. Start. If there are no significant fuel system leaks, the engine should remain running. If it starts, then dies, repeat the bleed process. If you bleed air during this, the problem is not the high pressure pump. You'll need to identify the air leak source.

This may not be the end of your issues, but it must be eliminated early if you have any chance of success. Let us know where this gets you.
1985 Blazer 6.2
2001 GMC 2500HD D/A
2014 Chevy Cruze Diesel - Fabulous car, no problems at all, but sold Nov. 2016 @ 55K miles.
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