Why does my Nissan Datsun fail to pull when ascending a hill even in low gears?

USA cars? or not? learn that cars are not the same world wide. ok?
will if you had shopped for the part the seller shows all cars it fits.
so why not learn to at least shop and learn that, for free
or at the dealer that sells it, oops TOO OLD (most parts are from them even 10 years old)
gee and fit is not the ONLY factor, the pressure it regulates must be in PSI spec, or injections will be wrong for sure. out of spec.
what car is the target car, the post is contradictory, sorry./
what car is busted.
89 to 92
93 to 89
then a 90 is told,????
off hand I SAY NO.
AND FOUR SURE NO USED FPR THAT IS GOOD, EVER
THE intenral diapharm is no good now. 33years old new is best
my wild guess is
the car TO RUN is (target runner) is 89 D21 PU.

D21 ,centric answers. OLD old old 1989
The D21 generation was the successor to the Datsun 720, sold as the Nissan Datsun Truck in Japan
this model was available worldwide !!!!!
The D21 series were called Nissan Hardbody in the United States/
so NO D21 here so said the wiki,
are you here
Nissan D21 (Chile)
12 engines used world wide.
The Nissan Pathfinder was derived from the Hardbody Truck and started in the same model year with chassis code WD21.
so AGAIN,what country is this 1989
and what engine is there, D21 list
the parts are NOt THE SAME, for sure FUELing. parts.

1.6 L Z16 I4
1.6 L NA16 I4[37]
1.8 L Z18 I4
2.0 L NA20 I4
2.0 L Z20 I4
2.4 L Z24 I4
2.4 L KA24E I4 (1990-1997)
3.0 L VG30i V6 (1986-1989)
3.0 L VG30E V6 (1990-1997) (no)
2.3 L TD23 I4 diesel (1987-1992)
2.5 L TD25 I4 diesel (1988-1996)
2.7 L TD27 I4 diesel (1988-1996)

Why change the engine for a transmission issue I wonder. .....

Check the engine codes for an idea of what the issue is.

The Datsun 1200 car was made by Nissan motor company limited. Why 1200 because it had an engine size of approximately 1200 cc. in Japan it was known as datsun sunny 1200. The car was Nissan chassis code B110. It was sold in Japan from 1970 to 1972, North America in Model years 1971 to 1973, New Zealand to 1974 and south Africa to 1976.
This information is from Wikipedia from datsun 1200 club page. Hope this was the information you were looking for

the rpm limiter will pull back the rpm to limp mode
select low range 1st gear or if automatic select manual 1st gear That will allow higher rpm at low speed

Pull the distributor and check if the gear on end of dist. shaft is attached. The roll pin holding the gear may have sheared off.

If it is not the distributor, check the timing chain still works.

This is normal if you are going up hill but if you go down hill there should be very little work for the engine and transmission to do.
Going up hill as the engine starts to pull it is normal to kick into a lower gear to give the car more pulling power. If it does it in the down hill mode you should get it checked like low fluid or something.

you can put any engine (and) transmission into your pickup you will need to
make the motor mounts and trans mounts and the drive shaft
but if you are trying to bolt the datsun motor to the nissan i dont belive'
this is coing to work i hope this helps you bob...

Is fuel pump working properly ?- sounds like you may have a case of fuel starvation under certain situations. Check for pressure being within specs.

Congrats on owning a Datsun 210. Okay back on topic. Here is a link I just found, I'm not sure how reliable they might be, 210 parts are rare since they are old. http://www.sunfor.com/nissan_inquiry/210_inquiry.html