SD25 Starting problems

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.

Moderators: plenzen, Nissan_Ranger

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richarddgr
Posts: 11
Joined: 4 years ago

SD25 Starting problems

#1

Post by richarddgr » 3 years ago

I have an old SD25 engine in a nissan forklift. it is very hard to start when it does it takes a long time to run smooth. I have had the injectors rebuilt, replaced the glow plugs, just took the injector pump in to have it checked nothing wrong. If I shut it off fro more than 5 minutes hard to start again. Anybody have any suggestions?
How is the injectors activated to atomize the fuel?

Thanks
Dick Edgar
Wyoming
Dick Edgar
DnJ Creations "in metal"
Cheyenne Wyo

Nissan_Ranger
Posts: 264
Joined: 13 years ago
Location: Canada

Re: SD25 Starting problems

#2

Post by Nissan_Ranger » 3 years ago

Are the glowplugs actually working?
The old 'six gun' was as popular as the cell phone in its time and just as annoying when it went off in the Theater.

richarddgr
Posts: 11
Joined: 4 years ago

Re: SD25 Starting problems

#3

Post by richarddgr » 3 years ago

Thay are all getting power to them.
Dick Edgar
DnJ Creations "in metal"
Cheyenne Wyo

plenzen
Posts: 867
Joined: 12 years ago
Location: Cochrane Alberta Canada

Re: SD25 Starting problems

#4

Post by plenzen » 3 years ago

Did this problem begin all of a sudden?

I ( like Nissan Ranger ) suspect the glow plugs are not heating up, or, the wrong ones were put in and have burnt out already.

Some of them are pretty fragile for burn time. A little too long on the button or the timed cycle and they burn out. There are quite a number of plugs that you can get for these engines. Some are quick glow some are not.
What kind of glow timer, or activation is on the forklift ?

Try removing them again and inspecting them to see that this has not happened. You can even apply 12V to them to see that they get red.

If they all check OK then do a compression test and see what's up there.

The injectors are activated by high pressure from the fuel pump. If the fuel injection shop rebuilt them I assume they tested them and you say that the pump has passed the test as well.
Retired Pauly
Problem with being retired is that you never get a day off.
1987 D21-J SD25 KC
KJLGD21FN

richarddgr
Posts: 11
Joined: 4 years ago

Re: SD25 Starting problems

#5

Post by richarddgr » 3 years ago

I will try all that when i get the pump put back in. The fuel shop said the pump passed all check points and is operating within factory specs. This has been going on since I purchased it. When I tried bleeding the system at the injector the fuel does not come out with any real pressure. Just seemed to dribble out of the line when cracked open. The pump has to pull the fuel out of the filter which was bled first. There is no visible means of assisted tank to filter.
Dick Edgar
DnJ Creations "in metal"
Cheyenne Wyo

plenzen
Posts: 867
Joined: 12 years ago
Location: Cochrane Alberta Canada

Re: SD25 Starting problems

#6

Post by plenzen » 3 years ago

The fuel systems on these trucks do not have to be bled at the injectors. It's a self bleeding system.
You do however that to bleed the filter assembly etc. Can you tell me what fuel pump you have on this ?
Is it the inline pump or a VE style pump. If it's the inline pump it will have to be bled as well.
There are two bleed screws at the top of the main body near where the injector lines come out.
If it's the VE style pump there is no bleeding procedure for it.

Keep us posted
Retired Pauly
Problem with being retired is that you never get a day off.
1987 D21-J SD25 KC
KJLGD21FN

Nissan_Ranger
Posts: 264
Joined: 13 years ago
Location: Canada

Re: SD25 Starting problems

#7

Post by Nissan_Ranger » 3 years ago

A flow volume test should be done to ensure that the fuel line from the tank isn't restricted or the tank sock plugged...

N_R
The old 'six gun' was as popular as the cell phone in its time and just as annoying when it went off in the Theater.

richarddgr
Posts: 11
Joined: 4 years ago

Re: SD25 Starting problems

#8

Post by richarddgr » 3 years ago

Thanks. I'll let you all know what i find out. We have a big snow storm coming in so I probably wont be able to work on it until next Friday.
Dick Edgar
DnJ Creations "in metal"
Cheyenne Wyo

richarddgr
Posts: 11
Joined: 4 years ago

Re: SD25 Starting problems

#9

Post by richarddgr » 3 years ago

I have the fuel pump back in (started to rain). 3 out of 4 Glow plugs would not heat. They were new. Does anyone have a recommendation for a glow plug to use? Im pretty much shut down until i get them in.

Thanks
Dick Edgar
DnJ Creations "in metal"
Cheyenne Wyo

plenzen
Posts: 867
Joined: 12 years ago
Location: Cochrane Alberta Canada

Re: SD25 Starting problems

#10

Post by plenzen » 3 years ago

How are they being cycled ?
Button or factory timer ?

I believe that Al did a whole page posting on glow plugs and their different specs. I will try and find it.
I personally use a Delphi plug and have had them in the truck for 5+ years now. I also have a bit different glow system. I will find the number of the plug I use and post it. It's already on here somewhere.
Edit
Delphi HDS 283 is the part number.
Retired Pauly
Problem with being retired is that you never get a day off.
1987 D21-J SD25 KC
KJLGD21FN

waynosworld
Posts: 502
Joined: 7 years ago
Location: Vancouver Washington USA

Re: SD25 Starting problems

#11

Post by waynosworld » 3 years ago

plenzen wrote:How are they being cycled ?
Button or factory timer ?

I believe that Al did a whole page posting on glow plugs and their different specs. I will try and find it.
I personally use a Delphi plug and have had them in the truck for 5+ years now. I also have a bit different glow system. I will find the number of the plug I use and post it. It's already on here somewhere.
Edit
Delphi HDS 283 is the part number.

What is different about your glow system compared to stock?
I know the voices are not real,
but they have some really good ideas.

plenzen
Posts: 867
Joined: 12 years ago
Location: Cochrane Alberta Canada

Re: SD25 Starting problems

#12

Post by plenzen » 3 years ago

The D21 had a glow system much like the Maxima with a quick glow and after glow feature. It was timed by a timer located under the drivers seat. There was also a temp sensor in the intake manifold to disable the afterglow timer if there was enough heat in the engine. It would also lessen the quick glow time based on engine and residual heat.
Retired Pauly
Problem with being retired is that you never get a day off.
1987 D21-J SD25 KC
KJLGD21FN

richarddgr
Posts: 11
Joined: 4 years ago

Re: SD25 Starting problems

#13

Post by richarddgr » 3 years ago

I finaly was able to work on the forklift. Everything is back together New glow plugs, the pump timing is set in the middle of the slot adjustment. It will crank over and wants to start but wont quite start. As soon as i let off the starter it quits. The fuel will pump through the hand pump to bleed but when cranking it doesn't look like it is flowing very regular through the clear return line. Is it possable that the fuel filter could be clogged up and not letting fuel into the pump even though the filter pump will prime? I havent replaced the fuel filter.

Thanks
Dick Edgar
Dick Edgar
DnJ Creations "in metal"
Cheyenne Wyo

plenzen
Posts: 867
Joined: 12 years ago
Location: Cochrane Alberta Canada

Re: SD25 Starting problems

#14

Post by plenzen » 3 years ago

Look for a scribed line on the casing/plate/cover surface that the pump mounts too. It will radiate out from the hole that the pump mounts into.
It can be a little hard to see and it will almost look like a scratch in the metal.
There will also be a tiny notch on the fuel pump mounting flange. It will look like a small nick like someone hit the edge with a screwdriver.

Line up the notch in the pump with it centered on that scribed line.
This is your ignition timing. ( much like moving a distributor on a gas engine )

What your describing sounds like the timing is late or retarded.
These engines are very sensitive to even 1 or 2 degrees either way.
Too advanced will make for a noisy idle and a kind of nailing sound, too late and makes them hard to start.

Are you sure that you got the pump timing correct, and the timing gear marks on the pump gear and the engine gear lined up correctly ?
Retired Pauly
Problem with being retired is that you never get a day off.
1987 D21-J SD25 KC
KJLGD21FN

Nissan_Ranger
Posts: 264
Joined: 13 years ago
Location: Canada

Re: SD25 Starting problems

#15

Post by Nissan_Ranger » 3 years ago

Yes. You need to check that you have sufficient supply of fuel...
The old 'six gun' was as popular as the cell phone in its time and just as annoying when it went off in the Theater.

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