Sd22 Runaway and diaphragm hunt

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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IDIDetroit
Posts: 13
Joined: 1 year ago
Location: Vernon, Florida

Sd22 Runaway and diaphragm hunt

#1

Post by IDIDetroit » 1 year ago

Hey, I have a 1982 Nissan 720 with an sd22 in it. I was coming home from work the other day and when I went to slow down for a redlight it wouldnt slow down and when I mashed the clutch in it was as if it were stuck at full fuel. I got it shut down and left it overnight because it was dark and the next day went back to retrieve it with a trailer. Every time you cranked it it would go directly to full fuel without any hesitation and I pulled the inspection cover off the side of the injection pump and there were little pieces of tin everywhere stuck in the plunger springs and the rack. I got all of that out of there and now it idles and throttles with the rack moving but I need to locate a diaphragm for the governor as it had a little tear in it upon removal. Any help in finding a replace for that or explaining what all of the tin was would be very much appreciated.

plenzen
Posts: 829
Joined: 11 years ago
Location: Cochrane Alberta Canada

Re: Sd22 Runaway and diaphragm hunt

#2

Post by plenzen » 1 year ago

Welcome to the forum

I cannot help you very much with your issue as I have different pump on mine and the SD's I worked on back in the day also had a different fuel pump.

Could you maybe post some pictures of what you collected and from where exactly it was you got them.

Those diaphragms are pretty scarce these days so good luck on your quest for one of those.
Retired Pauly
Problem with being retired is that you never get a day off.
1987 D21-J SD25 KC
KJLGD21FN

waynosworld
Posts: 417
Joined: 6 years ago
Location: Vancouver Washington USA

Re: Sd22 Runaway and diaphragm hunt

#3

Post by waynosworld » 1 year ago

IDIDetroit wrote:Hey, I have a 1982 Nissan 720 with an sd22 in it. I was coming home from work the other day and when I went to slow down for a redlight it wouldnt slow down and when I mashed the clutch in it was as if it were stuck at full fuel. I got it shut down and left it overnight because it was dark and the next day went back to retrieve it with a trailer. Every time you cranked it it would go directly to full fuel without any hesitation and I pulled the inspection cover off the side of the injection pump and there were little pieces of tin everywhere stuck in the plunger springs and the rack. I got all of that out of there and now it idles and throttles with the rack moving but I need to locate a diaphragm for the governor as it had a little tear in it upon removal. Any help in finding a replace for that or explaining what all of the tin was would be very much appreciated.

Try reading this thread, it has the part numbers you want in the first post.
http://nissandiesel.dyndns.org/viewtopi ... =1305#1305
I know the voices are not real,
but they have some really good ideas.

IDIDetroit
Posts: 13
Joined: 1 year ago
Location: Vernon, Florida

Re: Sd22 Runaway and diaphragm hunt

#4

Post by IDIDetroit » 1 year ago

I think this is how you post pictures, this is where I retrieved the stuff out of the pump and the largest piece, all of the debris was similar besides being smaller pieces. It was all up in the plunger springs.



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plenzen
Posts: 829
Joined: 11 years ago
Location: Cochrane Alberta Canada

Re: Sd22 Runaway and diaphragm hunt

#5

Post by plenzen » 1 year ago

I'm trying to find an exploded view of your pump to see what the heck that was. I'm thinking a deflector of some kind that directs spray or something like that for lubrication.
Heat shield maybe ??
I know there is a picture on here someplace of the VE style pump that Al did some explaining on the CSD device but not sure if there is an inline pump view.
Retired Pauly
Problem with being retired is that you never get a day off.
1987 D21-J SD25 KC
KJLGD21FN

IDIDetroit
Posts: 13
Joined: 1 year ago
Location: Vernon, Florida

Re: Sd22 Runaway and diaphragm hunt

#6

Post by IDIDetroit » 1 year ago

I didn't even think of it possibly being an oil deflector but whatever it was came apart and stuck the fuel rack open

waynosworld
Posts: 417
Joined: 6 years ago
Location: Vancouver Washington USA

Re: Sd22 Runaway and diaphragm hunt

#7

Post by waynosworld » 1 year ago

Did you have this piece of metal held by the two bolts that hold the cover on?
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I know the voices are not real,
but they have some really good ideas.

IDIDetroit
Posts: 13
Joined: 1 year ago
Location: Vernon, Florida

Re: Sd22 Runaway and diaphragm hunt

#8

Post by IDIDetroit » 1 year ago

No I don't, it wasn't there when I took it apart, that does look like what all of the debris were at one point. Was that an oil deflector?

waynosworld
Posts: 417
Joined: 6 years ago
Location: Vancouver Washington USA

Re: Sd22 Runaway and diaphragm hunt

#9

Post by waynosworld » 1 year ago

Well I am not sure the exact way it mounts, but it is something like this in the photos below.
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I know the voices are not real,
but they have some really good ideas.

IDIDetroit
Posts: 13
Joined: 1 year ago
Location: Vernon, Florida

Re: Sd22 Runaway and diaphragm hunt

#10

Post by IDIDetroit » 1 year ago

Is it necessary for that to be in the pump? If so does anyone know where I could find one?

waynosworld
Posts: 417
Joined: 6 years ago
Location: Vancouver Washington USA

Re: Sd22 Runaway and diaphragm hunt

#11

Post by waynosworld » 1 year ago

I am sure it has some kind of function, hard to say if it is needed/required.
My question would be how it got chewed up in the first place, did someone take it apart and then put it back together wrong?
I know the voices are not real,
but they have some really good ideas.

plenzen
Posts: 829
Joined: 11 years ago
Location: Cochrane Alberta Canada

Re: Sd22 Runaway and diaphragm hunt

#12

Post by plenzen » 1 year ago

I would say that it's there to direct lubrication towards the plungers, or, to keep oil from spraying directly against that cover like a crankshaft slinger does for the front seal. How it became loose and got chewed up by the plungers is another mystery. Finding one may be a "quest". I would suggest visiting a diesel fuel injection rebuild shop and print picture of what Wayne posted and asking. It may be a common part that crosses many 4 cyl inline pumps.
Maybe.
Are you sure you dug all the bits out of there ? If that's the biggest piece you got I would be wondering where the tiny bits have gone ?
Retired Pauly
Problem with being retired is that you never get a day off.
1987 D21-J SD25 KC
KJLGD21FN

IDIDetroit
Posts: 13
Joined: 1 year ago
Location: Vernon, Florida

Re: Sd22 Runaway and diaphragm hunt

#13

Post by IDIDetroit » 1 year ago

I don't think anyones taken it apart before me. I got the truck out of a field for free because they were going to town and it started loosing power and quit. When I got it I had to put an electric transfer pump on it in place of the mechanical one because it wouldn't pump once it got hot and a clutch master cylinder. I've been driving it daily for about a year and it did this without warning. I'll double check and make sure I got all of it out of there before I go back to driving it if I can find a diaphragm for the governor. All in all this just sucks because I had new tires and everything on this rig, I hope I can get it back together pretty soon because 15 mpg is killing me.

plenzen
Posts: 829
Joined: 11 years ago
Location: Cochrane Alberta Canada

Re: Sd22 Runaway and diaphragm hunt

#14

Post by plenzen » 1 year ago

They are cool little trucks for sure. If you can find the bits and pieces you need it will tick along for many years. Depending of course how it was treated in its early life. Just rolled 400,000 kms on my 87. You can reach out via PM to a few of the members on here to see if any of them may have a trashed pump lying around and have a look for that deflector/shield/whatever. Not as much traffic on here as there was a couple years ago, but pretty sure a lot of the email addys still work.
Got a couple of guys in Australia as well.

Al Savage (forum administrator and minor deity ) is also a good source. A PM to him might not hurt. He does not come on the forum that much these days and just checks to see that the magic that keeps this site working is operating.
Fuel injection rebuilders are a pretty good resource as well. There must be lots of them in the Fla. area.
Retired Pauly
Problem with being retired is that you never get a day off.
1987 D21-J SD25 KC
KJLGD21FN

IDIDetroit
Posts: 13
Joined: 1 year ago
Location: Vernon, Florida

Re: Sd22 Runaway and diaphragm hunt

#15

Post by IDIDetroit » 1 year ago

I love the little thing, great fuel mileage and it hasn't used much oil. The last oil sample I run just for kicks said that she was perfectly healthy to have 270000 km on her. I was even going to get some better paint and get the Ac working before all of this happened but oh well, she needs to be right before I do anything else. I'll check around some of these old timey fuel injection places around here to see if they have anything. Thanks for all the help and when I find the stuff I'll update you all if I have anymore problems with it.

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