SD25 doesn't stop and some other small issues :)

Dealing with all subsystems specific to the diesel powered Datsun-Nissan 720 pickup trucks.

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Posts: 5
Joined: 8 years ago
Location: Ankara / TR

SD25 doesn't stop and some other small issues :)


Post by nakturk »

(short intro: Turkish guy @41)

I've a '86 SD25 4x4 Crew Cab, 209k kms on odo.

Most mechanics around here have newer saw a 720, not even a SD25. Not much parts accessible if not usable from newer Nissans.

Here are my biggest headaches nowadays, very eager to hear suggestions:

1. Most of the time I can't stop the engine. Even I remove the key it takes around 2-3 minutes till it stop. What could be wrong ?

2. Black smoke, It used have almost none, but after an oil change, it smokes at low rpms on high gears. If I drop down one gear then no more smoke. But on this lower gear I then have to go very close to redline.

3. My tach needle, it shakes like crazy. Almost 90% of the time, for some reason it works ok on the rest, very annoying. Any ideas about what to check ?

thx for any comments, suggestions.
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Location: Cochrane Alberta Canada


Post by plenzen »

Good day and welcome to the forum

First need to know what fuel pump is on your Nissan.

If it has the VE style pump then I suggest that perhaps the fuel shut off solenoid my be sticking partially open when the power is cut from it and taking some time to seat and shut off the fuel

If it does not have the VE style pump and has the inline type then there are some threads on this forum about the DPC controller and how to go about fixing it.
A lot of people have just done away with it and put a cable on it to shut down. This lever may have some affect on your smoking as well.

Have you had the injectors serviced? Leaky injectors will cause smoking at idle as well.

Tach needle jumping,
Is it an electronic tach or cable driven ?
Low RPM shake may have something to do with the tach pick-up in the alternator.
Cable driven may be a burr or busted wire on the inner drive cable.

Those are all the suggestions that I have for you and I am sure that there will be some other fellows here offer some suggestions.

Retired Pauly
Problem with being retired is that you never get a day off.
1987 D21-J SD25 KC
Posts: 5
Joined: 8 years ago
Location: Ankara / TR


Post by nakturk »

Thank you, I'll try to figure out my pump type and tach type.
1986 Double Cab 4x4 SD25
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