OK, finally the combination of owning a compression tester, a warm day and some free time came together and I checked the compression.

Cylinder #1 and #2 are great at around 330 and 340 PSI, respectively.

The compression tester then started to leak (the quality!) so the needle would fall slowly. The pressure still went well above 300 PSI, I'd estimate around 320 PSI.

Cylinder #5 measured around 280 PSI, which isn't as good as the others but should still be ok. It's also probably higher since the leak of the compression tester seemed to get worse.

The verdict is that it's not the compression that is keeping the engine from starting.

I also noticed quite some layer of carbon on the injectors. I imagine some is normal (we all know these engines produce smoke) but since I have never pulled injectors before I don't know how much is normal.

The next thing I will try it to put everything back together and change the seal washers on the banjo nut at the inlet of the injection pump (see previouse post).

To be continued...

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84 300SD with Greasecar vegetable oil kit. Boston, MA