Help nissan 720 sd22 diesel

[waynosworld]

Having the relay is the most important to me, maybe this person has the stock glow plug timer on the passenger side kick panel, it all depends on what the former owner of the truck jury rigged in the past.

The good news it starts and runs flawlessly which was the battle when the thread was started, the rest is bells and whistles.

I use the relays for other things like the intake air warmer, I wish it was on a timer instead of a toggle switch, but it has a light to remind me to turn it off, a buzzer or something loud would be better but likely would get annoying.

I also used the same relay to force the starter motor to run when it would engage the flywheel but would not run, aftermarket solenoids are garbage.

[plenzen]

I had my air heater hooked to come on with the GP timer and also had it hooked to a push button on the dash so I could run it separately.
I could pre-heat the air heater for 20 seconds and then turn the key on and it would come on again with the glow plugs. My glow system it had an afterglow feature that would keep the GPs on at reduced power ( 8 or 9V) after the engine started for a varying amount of time depending on ambient temp.
I had the air heater stay on at full 12V while that happened. It would smooth out quite nicely on -15C days and even on the -25's.
It had of course been plugged in with the in block frost plug heater as well as an inline heater in the lower rad hose.
Once it ran it would start easily the rest of the day, however would complain if it sat for 4 hours in that kind of cold.
It was also equipped with dual batteries which help for cranking as well.

I recall some threads on here about the DPC controller and fixes, problems, work arounds etc.
As I recall it was kind of complex in its workings and settings etc.

Glad mine didn't have that.

Good he got it started.

[Raptor6717]

The glow plug timer is completely gone. It's just switch on the dash, which I believe has gone bad. When I jump the gp wire straight to the battery, the engine starts.

I needed some glow plugs so I could fill another engine with the old ones. I just bought some cheap ones.

I changed the alternator and it charges, but one of the bolts broke and the vacuum pump leaks oil. I will have to fix that.

[plenzen]

Likely the O rings as they get hard and crack from heat cycles etc.

There are 2 of them. One where the pump mounts to the alternator and one in between the vein body and pump body.

Nissan Part numbers that I have in a book that I still have, (I don't know why)
15056-2W203 Nissan number for the bigger of the o rings.
The kit that had both was 38531051.
It was not a Nissan part and I cannot recall the mfg,
I got it from my alternator rebuild guy.

That may be a resource for you there if you can find a rebuild shop that does diesel engines etc. The vacuum pump is pretty common.

I would get a push button and ensure that you use a good relay for the glow plugs.
Be cautious of glowing them for too long as the newer ones, like Wayne said are a bit fragile.

[waynosworld]

Do you still have the other alternator with the vacuum pump on it, maybe change out the vacuum pump, try to transfer it complete without the pump coming apart into more than one piece.

[Raptor6717]

That's what I did. The spline is too big. If I would have left it alone I wouldn't have broken the bolt. It doesn't matter, the bolt is still stuck in the alternator anyway

[Raptor6717]

*Update*

The bolt us out. The alternator is back on with the original vacuum pump. Now the brakes don't work. The vacuum pump is not working. The top hose is loose with the bolt tight. I don't know how to get it tight. I have tried using washers, but the hose still isn't tight. How do I get it tight?

[Raptor6717]

It just squeaks the belt when I press the brakes and the pedal is rock hard

[plenzen]

If you could post a picture of the "hose(s)" you refer to and the fittings you are using it would be handy.

The pump spins freely yes ?

The shaft/splines on the new alternator are the correct size/length ? or did you reinstall the original alternator ?

Did you take the pump apart at all ?

With the engine running and the "hoses" removed can you feel vacuum where the hose attaches ?

[Raptor6717]

20260814_163357.mp4

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[plenzen]

I've watched that a number of times and the "squealing" is because that belt is way too loose in my opinion.
You should not be able to free wheel that fan on the alternator that easily.
The the hose fitting appears to be missing the washers from the banjo bolt.
They are typically a copper washer but aluminium crush washers will work as well.
Do not crank too hard on the banjo bolt because if you break it I would think it will be very difficult to find.
I think once you tighten the belt and get that fitting sealed it will work.
The belt is so loose that the load from the vacuum pump is causing it to slip and your brake pedal is rock hard because there is no vacuum getting to the booster.
There is supposed to be a crush washer to go on both sides of that banjo bolt as well.
It's meant to be sealed much the same as a brake hose to a caliper.
You can get the crush washers if you need them from a parts store. ( standard flat washers wont work )
I cant tell if you have stacked fittings on the pump or just the one, but if you have stacked fittings then a crush washer between each side of each fitting is required.

[waynosworld]

I have always had an issue with finding the belts for the alternator for the diesel engines, so have others as more than one time I have bought a Diesel truck with an extended alternator bracket.
There is not a lot of adjustment room either, if the belt is much smaller/shorter one cannot get the belt on, generally I just buy the next smaller size of the belt you have and call it good, maybe buy the two next smaller belts and take back the one that did not work.

[Raptor6717]

Yeah the belt is maxed out. It's old. I fixed the vacuum hose, I just forgot the washer. I replaced a couple fuel lines, hopefully that helps with the long cranking time.

[plenzen]

I wish I still had the part number for them.
They were a weird size/configuration.
I want to say 13mm and they were hard to find.
Dayco I believe was the name I had.
They also had some odd angle for the pulley as well. Different from an automotive type "V" The shallower V allowed them to sit higher in the pulley and then it made them a titch shorter for the same length of belt if that makes sense.
IIRCC I went to a truck outfitters place rather than a auto parts place like NAPA etc to find them.