little help with SD23

SD diesels were widely available in the US in the 1981-86 Datsun/Nissan 720 pickups, and in Canada through '87 in the D21 pickup.

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DeadlySD23
Posts: 4
Joined: 7 years ago
Location: Finland

little help with SD23

#1

Post by DeadlySD23 »

Bought me a -83 pickup SD23 here in Finland a month ago. the problem is it loses power when i driving and usually stops on the road, but sometimes you can start again and drive of like nothing has happened.
About once a week you can`t drive it at all until you get back home and start it later during the day.

I have changed the fuelfilter and the primer pump. there is no leak from the tank to the engine and the fuel have no water or dirt in it.
I have new injector nozzle.
The car starts fine when its cold and warm.

Any ideas what it could be??

(sorry for the bad english)
Datsun 720 2.3D 1983
waynosworld
Posts: 525
Joined: 8 years ago
Location: Vancouver Washington USA

Re: little help with SD23

#2

Post by waynosworld »

DeadlySD23 wrote:Bought me a -83 pickup SD23 here in Finland a month ago. the problem is it loses power when i driving and usually stops on the road, but sometimes you can start again and drive of like nothing has happened.
About once a week you can`t drive it at all until you get back home and start it later during the day.

I have changed the fuelfilter and the primer pump. there is no leak from the tank to the engine and the fuel have no water or dirt in it.
I have new injector nozzle.
The car starts fine when its cold and warm.

Any ideas what it could be??

(sorry for the bad english)

Does it have a pre-filter?
If you are not using the correct pre-filter, it sometimes only lasts a few hours, it collapses and cuts the fuel off, once the engine dies and quits trying to pull fuel out of the tank, it releases and allows fuel to flow again for a while till it collapses again.
Does your truck have a lot of rust?
Sometimes if trucks sit a long time, the tanks start to rust, some of the rust flakes that fall on the bottom of the tank float around till they plug up the end of the pickup tube in the tank, fuel then cannot flow, when the engine dies, the fuel pump quits trying to pull fuel into the pick up tube, the rust falls off the end of the tube, and then it will start again once primed.
These are just things I have had happen to me in the past, my engine would start missing and slow down till it stopped, I then could prime the system and start it up again, but it would die again because of the poor quality pre-filter or rust would plug it up again.
I know the voices are not real,
but they have some really good ideas.
DeadlySD23
Posts: 4
Joined: 7 years ago
Location: Finland

#3

Post by DeadlySD23 »

No i dont have a pre-filter. so there is no filter in the tank just a tube that suck fuel?
the car goes pretty god when i have full tank but after a couple of days the things hapened.
I guess the tank don't have a inspection hatch?

does anyone know if there is a filter in the injection pump?

(Thanks for the answers)
Datsun 720 2.3D 1983
plenzen
Posts: 869
Joined: 14 years ago
Location: Cochrane Alberta Canada

#4

Post by plenzen »

No filter in injection pump.

2 things come to mind

1. It may be sucking air from someplace and simply running out of fuel

2. Tank may not be venting and when you get to 1/2 tank or less there is too much vacuum in the tank that wont allow the pump to draw any more fuel.

Next time it quits remove the filler can and see if you cant hear what sounds like hissing. May simply be a bad filler cap where the vent valve is stuck.

Easiest way to rule this out would be to leave the fuel filler cap loose and see if the problem goes away.
With what you say about parking it for a while and then being able to drive it i suspect this may be the case.

It may also be what wayne tells you and the pick up in the tank is collapsing as well. See if you can get that out and inspect it.
I believe there may be a drain plug on the bottom of the tank as well. This may give you and indication as to how much rust and junk is in the tank.

Paul
Last edited by plenzen 7 years ago, edited 1 time in total.
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1987 D21-J SD25 KC
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DeadlySD23
Posts: 4
Joined: 7 years ago
Location: Finland

#5

Post by DeadlySD23 »

Yes i did check the filler cap at one time and didn't here anything. I have also checked the ventvalve and it worked fine.
tomorrow i will tear the tank in smithereens and check it out!
I will let you know how it goes.
Datsun 720 2.3D 1983
elminero67
Posts: 143
Joined: 11 years ago

#6

Post by elminero67 »

I would try running it off a temporary tank with new lines to isolate the problem-just buy some diesel fuel line and a five gallon fuel can. If it runs well the problem is in the fuel tank or lines. If the problem persists it is not. You can even use a clear plastic fuel filter (gasoline) on a temporary basis. You don't want to use one permanently as it does not allow enough diesel fuel to pass at full throttle.
DeadlySD23
Posts: 4
Joined: 7 years ago
Location: Finland

#7

Post by DeadlySD23 »

cleaned the tank today, no rust flakes or anything just a little bit of sand.
but when i have drained the tank about 1/2 from the plug i opened the filler cap and heard a hissing noise so perhaps i should drive with the filler cap off and see.
Datsun 720 2.3D 1983
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asavage
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#8

Post by asavage »

Read Tale of woe about using the wrong inline fuel filter.

Read Amusing fuel system stories.

Read about how to use a vacuum gauge to diagnose fuel system restrictions.
Regards,
Al S.

1982 Maxima diesel wagon, 2nd & 4th owner, 165k miles, rusty & burgundy/grey. Purchased 1996, SOLD 16Feb10
1983 Maxima diesel wagon, 199k miles, rusty, light yellow/light brown. SOLD 14Jul07
1981 720 SD22 (scrapped 04Sep07)
1983 Sentra CD17, 255k, bought 06Jul08, gave it away 22Jun10.
spajetti
Posts: 2
Joined: 7 years ago

Re: little help with SD23

#9

Post by spajetti »

maybe there is air in the fuel lines
JonJon
Posts: 1
Joined: 6 years ago

Re: little help with SD23

#10

Post by JonJon »

Try checking the engine starter/solenoid and alternator connections check it if the screws and wire connections are tightly in place.. because if not.. your pick up will have a hard time starting because of insufficient power/electrical distribution.. Thus, having you the feeling of something is about to breakdown.. Parts unknown :?:
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