I just got my hands on an 89 Nissan PU with the 2.4L 4cyl.
When starting cold it will tourn over then abruptly stop...groan slowly....and turn over again a few more times.....groan slowly....turn over again a few more times till it fires up.
Is this a compression issue? Its almost as if the motor is locked up.
Once it starts it runs fine. And starts back up again very easily after its warmed up.
The issue only happens when the engine is cold.

Probably a bad starter, bad battery, or combination therof, if you ask me.

sounds like what happens when a battery is not quite dead but not too alive. I would check the obvious like oil level and maybe swap a known good battery in there for a test when its cold one morning. When i read your post again it sounds like the battery is very low but when turning over the alt gives a bit more juice and the power to the starter goes up then its quickly used up again and then it wants to rely on the weak battery and starts the cycle over again. Or it could be a bunk starter. I think.

Just make sure you dont fry your alt from trying to charge a bad battery if it is bad. You could also remove each power connections one at a time and clean the contacts up then install nice and clean and tight. The ones at the starter are the ones that usually give the trouble.

I dont know if your truck has a solenoid external relay for the starter like my truck but that thing could give problems like you describe.

If any of that changes the symptoms but doesnt cure them you can either test or replace the battery and starter cables. I would check the connections on the back of the alt just to make sure. Your already there.

I hope you can figure out the problem easily cause it could be next to impossible sometimes. The older vehicles always need their terminals and connections attended to in some form or another cause of metal corrosion and deterioration from vibration or other sources. keep us posted.

The starter is brand new. But the battery terminals need a good cleaning....they are extremely corroded.

Its very consistant...turn, turn, turn, slow grooaaaaning turn, turn turn turn slow grooaaaaning turn, etc... Exact pattern. Thats why I was wondering about compression or maybe even a leaky injector.
But I will try cleaning the terminals, and maybe a new battery. But the starter is definately new.

Brand new or new rebuild...big difference.

Actually I had a starter die in my ford so I went and got a (NEW) one at my auto parts place and slapped it in. It was about a week and the starter died. So i took it back and got a new, new one. Before I put it in I went on my ford forum and looked around a bit at the battery issues. Ford didnt put in a thick enough cable for the battery and starter circuit so the wires could short or whatever and cause huge resistance and kill starters. So i slapped a few extra larger guage grounding wires and a new huge starter cable. I then put my new, new starter in and it has been good ever since. It even rotated quicker when cranking with the new cables so i know they were a little too small. Now for the question "did my cables fry my starter or did I get a bad one?" 300,000km and nobody changed the origional cables until me. It could not have been a problem before and was it a problem now? I could not tell you But I may have gotten a bad new starter.

What you describe is low current to the starter motor, possible causes include weak battery, corroded terminals, bad cables, bad ground (check this in an older car/truck), weak solenoid, shot brushes/armature in starter (should not be with rebuild/new...but seen bad armatures before...).

Start by cleaning terminals and checking battery and ground cables, bet they're corroded out...and checking them costs little...

I couldn't tell you if its a rebuild or a new starter. It was replaced about a month ago. But I like the idea of the battery cables for the Pos and Neg and cleaning my terminals up. Like I said before...the terminals are really really coroded.
If I can find a good deal on a new battery, I may even replace it. But I'll clean the old one first.

I only paid $300 for the truck. Really don't want to sink a bunch of $$ into it. Its just going to be my powered wheelbarrow for mulch, lumber, firewood, trips to the dump, etc. Its not a daily driver. Will stay parked most of the time.

Clean up the corrosion then have the battery tested at Advance, AutoZone, etc for free.

Also, make sure the cables are good after cleaning the terminals... sometimes the corrosion can get into the actual copper wire itself, especially if the OE terminals have been replaced with those repair terminals sold at automotive supply stores for a few dollars.

Also, as stated earlier, the starter is still suspect especially if it was rebuilt.

Is this Hardbody automatic? D21/WD21 vehicles with automatic trans didn't have a starter relay so the current had to travel through a considerable length of wire. This can be rectified by installing your own relay. See this thread - unfortunately the wiring diagram seems to be missing, but the description should help get the point across.

No, its a stick shift.
I may go this weekend if I have time and look into new cables and clean up the batt really good.
Oh yeah....and some new oil and a filter! LOL!!

OK. If this manual truck is 4WD, you need to overfill the transmission due to improper placement of the fill hole in the transmission casing. See here for more info.

Nope, just a 2 wheel drive, base xtended cab. Stick shift with 200k miles.

Okay, no need to overfill then. Good luck with getting it to run!