D7-3T Starting problem

I would say the head gaskets are ok, bleed the inj pump and lines, check the valve adj, and make sure the decompression linkage works as should, and im sure you will get more info on here.

If all you say is working right then most likely it is a tuckered out engine. Just not making the compression pressures needed to get ignition without long cranking periods.

Look at the blowby coming out of the crankcase breather. Probably is increased over what it was a few years ago. Just another sign of a well worn engine or sticking rings.

Could also have the injectors checked so you know they are in good shape and time the injection pump lifters to account for the wear that inevitably occurs which delays the injection timing.

Check the connections from the air cleaner to the engine, look inside the manifold for dirt...if the starting behavior has changed fairly quickly, these are classic symptoms of a dusted engine.

Those are some good check list items.

If it runs good once you get it going I wouldn't suspect the injectors. Usually if it's a compression related issue the starting effort becomes more noticable with time....and change in ambient temperature.

These engines are huge heat sinks and unless you can make ignition temperature (requires about 750 deg. F. cylinder temp) they will not start at all. You need good compression and heat transfer (no carboned up heat exchanger) from the pony to get er going.

When mine was like that, it was a porous cast head seeping a tiny, tiny bit of water into the cylinders which corroded the sleeves and caused compression loss. I hope your problem is a lot simpler than that.

Thanks to all of you for your ideas.
I hope that it is only a problem with the fuel supply side and I will check the injectors. If not than I've got some major work to do.
Here is a couple shots from last weekend after I got it going

I have a D7-17A that had a similar problem last year. When the main engine was started with the starting engine the main engine would fire on three cylinders and the fourth cylinder would start firing about 30 seconds after the engine was running. This problem had been going on for several years and I though nothing of it until one day I was running the dozer and it started to knock like a rod was coming loose. It turned out to be a problem with one of the individual cylinder diesel injection pumps. After replacing the defective injection pump the main engine now fires right up on all four cylinders without missing. This might be your same problem. Get a new cylinder injection pump and install on one of the cylinders that is missing or swap places with one of the pumps on a good cylinder with one that you know is missing and see if the missing problem changes cylinders.