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Discussion Starter · #1 ·
Hi all, I actually have a 1980 Scout II with the Nissan Diesel but the Scout forums arent super helpful. I recently started having an issue where after a short time of driving the engine would become very sluggish and lose all power. I have had to limp it home at 10mph in 2nd gear with the pedal to the floor for several miles, and had to keep the accelerator pressed in just to keep it from dying even in neutral. It sounds like it is down 2 or even 3 cylinders. When I got to my street it died completely, wouldn't re-start, and I had to push it home. I tried starting it again a few hours later and it just coughed and sputtered so I drained the tank, flushed the lines, changed the fuel filter, ran some injector cleaner through it, and put in some fresh diesel and it started right back up again and after a few minutes of running seemed to be normal again, so I chocked it all up to bad fuel.

I took it on several very short trips, dropping kids off at school, etc and had no trouble for the next few days. It died again today in almost exactly the same spot as I was leaving my house and again I had to limp it home at 10-15 mph. This time I didn't have to push it the last leg, and in fact when I got to my house it seemed to get a bit of a second wind and I got it into the garage. I went out a couple hours later and without doing anything to it, it started up and revved smooth like nothing ever happened so I drove it around the block and it seemed completely fine. Engine temp and oil pressure are all normal and nothing is leaking out of it anywhere (other than a slow drip from the oil pan gasket that I haven't fixed yet).

So my question is does anybody have any idea what the hell is going on? Why would I be losing cylinders once the engine is fully warmed up, or is that even what is triggering it? I am very comfortable around old gas engines, especially chevy but I am extremely hesitant to tear into the SD-33 considering how expensive a mistake could be, and no diesel shops in Austin will touch it. Thanks!
 

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Rust is just natural weight reduction.
1986 SD33T SWB
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Sounds like you're on the right track with the fuel system. When you replaced the fuel filter, did you clean out the banjo filter? Its in the banjo bolt of the fuel inlet line to the lift pump.
Do you know the internal condition of the fuel tank? If the car hasn't sat for a long period of time with no fuel, it should be ok, but that does not mean it will be. Did any rust or crap come out when you drained it? If so there may still be stuff in there.

I'd also go through and check all rubber lines for degradation and all connections and clamps - ensure they are tight and cannot suck air

When it loses power, does it happen under the same circumstances? I.E high boost, foot to the floor etc? Is there any smoke?


Pretty cool to have a Scout with an SD33T too, pretty rare cars, and very cool.
 

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nissan patrol y61 td4.2tdi
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Hi Kenny01,
first check for the old bugbear of a blocked fuel tank breather whether it be in the filler cap or an external line to somewhere on the chassis--mud daubers love open holes to nest in.
Another issue could be that a rubber fuel suction or supply line could be de-laminating inside where you cannot see--remove and check for such.

From memory there should be a banjo bolt at the fuel supply banjo fitting coming in to underneath the transfer pump----remove that and check if a screen there is blocked.

A couple more things to check like something floating around in the fuel tank that gets sucked onto the fuel transfer pump pickup tube or wraps around or clogs the sock type filter often used on fuel tank pickup tube ends in the Scouts time frame.

I have had crud block the sock on my just converted to Diesel GM Holden gasoline powered car that I re-powered with a Nissan ED33 truck engine--With Diesel in the tank it loosened all the accumulated crud and it blocked the sock halfway up a mountain--took all the blow I could muster by mouth to get some reverse flow into the tank and part clear the crud from the sock. Had about six shudder to a stop issues on the way to our campground.
During my stay I removed and cleaned the sock about 8 times before I could get a stop free run--never touched it again after that.
The clue was that the priming pump, on the side of the fuel transfer pump on the injection pump, that when I tried to pump the pump plunger it was sucked back down by the suction created in the supply line--the knurled knob unscrews to allow pump to pump--be sure to re-screw it down or air can get in the system and cause rough running.

Pieces of clear plastic or even lenses from torches have been found floating about in fuel tanks and so are very hard to spot and get out and so are easily missed.
You could also check the check valves in the transfer pump--some are steel and some are nylon which can get sand or such embedded in them causing low transfer pump pressure. Both types of valves and their seats can be gently rubbed on/with fine emery to clean up the seats.

Lets know how you go and we can maybe help more if these simple first stage trouble shooting checks prove to be OK.

Cheers,
Eddie B.
 

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Discussion Starter · #4 ·
Sounds like you're on the right track with the fuel system. When you replaced the fuel filter, did you clean out the banjo filter? Its in the banjo bolt of the fuel inlet line to the lift pump.
Do you know the internal condition of the fuel tank? If the car hasn't sat for a long period of time with no fuel, it should be ok, but that does not mean it will be. Did any rust or crap come out when you drained it? If so there may still be stuff in there.

I'd also go through and check all rubber lines for degradation and all connections and clamps - ensure they are tight and cannot suck air

When it loses power, does it happen under the same circumstances? I.E high boost, foot to the floor etc? Is there any smoke?


Pretty cool to have a Scout with an SD33T too, pretty rare cars, and very cool.
Thanks for the reply, you are right about Rare which is cool but makes it very hard to find help or parts. When my alternator died I bought one for a 1988-1997 Nissan Patrol off E-bay and cut the brackets to make it fit because a rebuilt one for a Scout SD-33 was $700. I did not clean or know about the banjo filter, I will go look into that tonight. My borescope is too short to reach all the way into the fuel tank but the fuel I pumped out (while a little cloudy) did not have any debris in it. In fact the color was a nice greenish yellow still. It smelled a little off but that may have been the diesel clean additive I put in. I probably should have dropped the tank completely but my wife gets migraines and is very sensitive to the diesel smell so was trying not to make her sick.

Both times it has happened I was driving about 50-55 mph in 4th gear, maybe 2500 rpm with very little boost, 1 or 2 psi tops. I often hit 4-6psi during acceleration without an issue. I didnt see any smoke, the engine just starts slowing down and shaking quite a bit, hence my suspicion that a few cylinders are not firing. Temp and oil pressure don't change. Been taking the kids to school in it for several days but its just a 2.5 mile round trip and very slow speeds so I doubt the engine gets up to temp. So the only thing I can think of is higher engine load in 4th gear and the engine fully warmed up. The part that is the most crazy is that an hour later I started it up and drove around the neighborhood like nothing ever happened, it was smooth as a baby's butt... or at least as close to that as an SD-33T will ever get.
 

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Discussion Starter · #5 · (Edited)
The clue was that the priming pump, on the side of the fuel transfer pump on the injection pump, that when I tried to pump the pump plunger it was sucked back down by the suction created in the supply line--the knurled knob unscrews to allow pump to pump--be sure to re-screw it down or air can get in the system and cause rough running.
I think you may be on to something there, the first time I am pretty sure it was bad diesel because it refused to start again the next day, (and the priming pump worked just fine) but today when I pulled over I checked the priming pump to see if I could get it to come back by pumping it a few times and when I pulled the knob out it was sucked back in. I am really glad you said that, guess I am dropping the tank after all, good thing I only put 10gallons in it. The photo shows what I assumed was the pick up pump and I see a banjo fitting on the top with something underneath it, would that be the screen? Thanks for the suggestion!
Motor vehicle Hood Automotive exterior Electrical wiring Gas
 

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Pass the Popcorn
Nissan Datsun Patrol
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Even though I know your in good hands with knowledgeable advice from the two previous members, I came across this link below with service manuals for an SD33T, which could help given there’s not much info in the states.

 
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nissan patrol y61 td4.2tdi
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Hi Kenny01,
the lower circled fitting should be where the filter is in /on the banjo bolt.
The type of supply hose fitting I see is a screw together re-useable fitting and have been known to grab the inner hose lining when assembling and part clog the opening--I would suggest checking any supply hoses with those fittings for flow rate--alas, with the 90# elbow it does not allow you to look into the fitting but you should be able to get some wire or weed wacker (grass trimmer) line to go in and check for lining failure as well as blowing some air thru the hose from the tank end (after draining the hose of course) may tell something.
Keep at it --"man made it so man can fix it"

Cheers,
Eddie B.
 

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Rust is just natural weight reduction.
1986 SD33T SWB
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I think you may be on to something there, the first time I am pretty sure it was bad diesel because it refused to start again the next day, (and the priming pump worked just fine) but today when I pulled over I checked the priming pump to see if I could get it to come back by pumping it a few times and when I pulled the knob out it was sucked back in. I am really glad you said that, guess I am dropping the tank after all, good thing I only put 10gallons in it. The photo shows what I assumed was the pick up pump and I see a banjo fitting on the top with something underneath it, would that be the screen? Thanks for the suggestion!
View attachment 535739
As edb has said, we usually see a banjo fitting where you have a 90 degree elbow.
From what I can see it seems Scouts originally had the banjo that we do, so I would hazard a guess that someone has been into that fuel supply system before.

Right where that 90 degree elbow goes into the lift pump there is a fitting, I would guess and imperial to metric or maybe a filter fitting. Perhaps it worth a look.

I would trust Eddie's judgement, he has a more extensive knowledge of these old fuel and injection systems than I do.
 

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Discussion Starter · #9 ·
Thanks so much to everybody for your very helpful suggestions. Sadly I have to go out of town this weekend so I cant work on it until next week but I will definitely post updates once I get the tank dropped and cleaned and check out the lift pump screen.
 

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nissan patrol y61 td4.2tdi
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Hi Team,
scan for Diesel Kiki transfer pump showing one possible location for inlet screen or screen can be around the outside of the banjo bolt and may stay in the banjo if badly clogged--look and see if screen is there if not in the centre of the bolt.
Cheers,
Eddie B.
 

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