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'97 Suburban 6.5 turbo diesel dies

When this first started, it happened only every two or three weeks. It just dies while driving. No warning. No bucking or coughing. Always when it’s warmed up. It will not start again. Then, 10 minutes later, it starts up fine, runs great for a few minutes and dies again. The dealer has had it three times. The last time they ran every test known to man, couldn’t find anything wrong with it and gave it back. It’s been with a diesel mechanic for over a month now. He’s replaced the fuel cap (I had put on a locking cap), fuel lines, and lifter pump. He also replaced the fuel injector pump, but that didn’t help, so he took it back off. Took out all of the fuel injectors, found one bad, replaced it and put them all back in. It will run for hours sitting in the lot. When he drives it a couple of blocks, it dies again. He’s at his wits end and so am I. Anyone have any ideas?

I am going to assume some one changed out all of the filters??? Some diesels have a water remover that needs to be drained every now and then as well… Not sure about your truck…

The only thing left is to drop the fuel tank and see if anything is growing in there.

Tester

This seems like it would be relatively easy to diagnose for a diesel mechanic. I mean, because it is a diesel. It it was a gasoline engine, it would be more tricky. But if it has a supply of fuel being injected into the cylinders, it pretty much has to run. With a diesel, you’d expect theproblem would be that it won’t turn off, not that it won’t continue to run.

It seems sort of strange to me that what they have done is replace the gas cap and the fuel lines and the injection pump with little to no justification. It could be any of those things, but a diagnotic test should point to what it is before making parts replacements. How much experience do you have with this shop and them fixing diesel engines? Are you certain the mechanic has a lot of diesel experience? It may be they simply are not tooled up to diagnose problems of this type, and a shop with a lot of diesel experience could find out what is wrong straight away. Not because the other shop has smarter mechanics, but that they have the diagnostic test tooling to figure it out. Just saying is all …

Follow Testers lead…There is probably a “sock” (fuel intake filter" inside the fuel tank which is getting plugged up with “things” floating around inside the tank…Your locking tank cap may have allowed moisture to enter the tank and that can lead to algae growth in diesel fuel tanks…Marine diesels are plagued by this…

Perhaps a funky intermittent injection pump issue? Or the fuel system is sucking in air somewhere under load? I know that anytime the fuel system is opened or worked on, it needs to be purged thoroughly. I own an '86 CUCV with the 6.2 diesel (same engine family) and they are not too forgiving with even the slightest amount of air in the fuel system.