Trouble starting

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.

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cseger1
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Trouble starting

#1

Post by cseger1 »

I have just finished replacing the motor in my truck with one from a lower mile truck. I got the injectors rebuilt and installed with some crush washers from McMaster Carr. Nissan was no help. They had the incorrect diagram from this thread and no washer for the end of the injector.

Once I had the fuel system put back together I bled the system. I pumped the lifter pump until fuel came out the 10 mm bleeder bolts on the IP. The pump never got firm like I expected. Does this indicate air trapped somewhere? Then I turned the motor over with the fuel line cracked open at each injector until fuel came out from there. Then I tried to start her. No dice.

I think it's a glow plug issue. I hot wired the plugs and only two of them warmed up. I think its time to replace them.
Christian
1981 720 SD22
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#2

Post by Nissan_Ranger »

Even when the fuel has started to squirt out of the loose nut, the injector itself still has to fill up and bleed out. That will take some more cranking. When it does fire up, don't be shocked if a few very loud knocks are heard; that is caused by small residual air bubbles in the pintle. It will straighten itself out and smooth up as the residual air bleeds out.

As far as the glowplugs are concerned, make absolutely sure that the connections are clean. This necessitates removal and checking of both the wire ends and the glowplug terminals. Some glowplug terminals have knurled aluminum nuts. Those are renowned for causing connection difficulties.

Let us know how it works out...

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.
cseger1
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#3

Post by cseger1 »

All of mine have the knurled nuts. I am going to bench test all of them and replace the wire loom from the timer. Good tip on the injector refill ranger. When I get the GP's tested and replaced I'll keep that in mind. Hopefully I'll have some time to work on it this week.
Christian
1981 720 SD22
cseger1
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#4

Post by cseger1 »

How about the hand pump never getting firm? Is that a problem?
Christian
1981 720 SD22
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asavage
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#5

Post by asavage »

cseger1 wrote:How about the hand pump never getting firm? Is that a problem?
On the SD's Inline IP: no.
Regards,
Al S.

1982 Maxima diesel wagon, 2nd & 4th owner, 165k miles, rusty & burgundy/grey. Purchased 1996, SOLD 16Feb10
1983 Maxima diesel wagon, 199k miles, rusty, light yellow/light brown. SOLD 14Jul07
1981 720 SD22 (scrapped 04Sep07)
1983 Sentra CD17, 255k, bought 06Jul08, gave it away 22Jun10.
cseger1
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#6

Post by cseger1 »

AAAAAAaaargh! I put two fresh Gps in and bench tested the others and no starting. I cranked a lot too, sprayed WD40 in it. No dice. I need to do a compression check but I don't have the tools.
Christian
1981 720 SD22
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asavage
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#7

Post by asavage »

Do this: pull all the GPs. Get an oil can (pump-type lubricating tool) for under $10. Don't use a funnel & hose!

Put four full squirts of motor oil in each GP -- more is NOT better, you can bend a rod if you put too much in. Reinstall the GPs, clean off the oil you spilled when you missed the GP holes, glow, crank as usual.

I have had several diesels that have sat and develop too little compression to start after sitting. One recent Toyota sat 3+ years, prelim test (a little light oil sprayed in, cranked with GPs out, then tested) was something like 410/300/0/130. After I got it fired up using the method above, ran it for a few minutes, retested, and it is now 440/430/440/440.

I've seen this kind of behaviour on several old diesels.

So I've come to want to do the lube-in-the-GP-hole for most of the old diesels I come across that have sat for more than a year.

I've found that even if you have a fuel injection problem, at the least it will fire up and run briefly on the oil you squirted in the GP hole.

Bear in mind that a GOOD battery is a must. If you can't crank it fast enough, there are no tricks that will work other than a steep hill or a tailgate-damaging push.
Regards,
Al S.

1982 Maxima diesel wagon, 2nd & 4th owner, 165k miles, rusty & burgundy/grey. Purchased 1996, SOLD 16Feb10
1983 Maxima diesel wagon, 199k miles, rusty, light yellow/light brown. SOLD 14Jul07
1981 720 SD22 (scrapped 04Sep07)
1983 Sentra CD17, 255k, bought 06Jul08, gave it away 22Jun10.
cseger1
Posts: 116
Joined: 14 years ago
Location: Houston TX

#8

Post by cseger1 »

asavage wrote:Do this: pull all the GPs. Get an oil can (pump-type lubricating tool) for under $10. Don't use a funnel & hose!

Put four full squirts of motor oil in each GP -- more is NOT better, you can bend a rod if you put too much in. Reinstall the GPs, clean off the oil you spilled when you missed the GP holes, glow, crank as usual.

I have had several diesels that have sat and develop too little compression to start after sitting. One recent Toyota sat 3+ years, prelim test (a little light oil sprayed in, cranked with GPs out, then tested) was something like 410/300/0/130. After I got it fired up using the method above, ran it for a few minutes, retested, and it is now 440/430/440/440.

I've seen this kind of behaviour on several old diesels.

So I've come to want to do the lube-in-the-GP-hole for most of the old diesels I come across that have sat for more than a year.

I've found that even if you have a fuel injection problem, at the least it will fire up and run briefly on the oil you squirted in the GP hole.

Bear in mind that a GOOD battery is a must. If you can't crank it fast enough, there are no tricks that will work other than a steep hill or a tailgate-damaging push.
Awesome tip Al. I'll give this a shot. I definitely have the cranking speed, today I did all my cranking through a 750 CCA battery while my tractor was jumping it. It spins very freely in a way thats not good. Freely, like there's no compression.
Christian
1981 720 SD22
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kassim503
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#9

Post by kassim503 »

Try a thumb compression check if its spinning really freely, it should blow your thumb right off the hole with good force.

Thatll only tell you that the rod is intact, valves are closing somewhat, and the rings are there, but may not be sealing well.
'83 maxima sedan, l24e, a/t, black

227K SOLD 6/7/2012
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asavage
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#10

Post by asavage »

kassim503 wrote:Try a thumb compression check if its spinning really freely, it should blow your thumb right off the hole with good force.
That's a recipe for embedding crap in your thumb, which then gangrenizes and has to be cut off. Don't put your thumb over the GP hole and crank with the starter. Use your kid brother's thumb instead!







j/k
cseger1
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#11

Post by cseger1 »

No dice. I tried the oil in the pre-chamber and got a small chuff from one of the cyls. Otherwise no real difference. The oil I squeezed in with my can did not ignite and run the motor. I did manage to break a brand new glow plug though. At least they said it was brand new. It was from B and A and it looks like it was spray painted silver. Very weird.

I think this leaky head may be more serious than I thought.
Christian
1981 720 SD22
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asavage
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#12

Post by asavage »

cseger1
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#13

Post by cseger1 »

Thanks for the offer but borrowing tools makes me nervous. I have the head off my old engine and it looks really good. I also have a spare head gasket so I think I am going to swap heads and do a visual inspection of the cyls. Hopefully if I need a new top end I can tell by looking.
Christian
1981 720 SD22
redmondjp
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#14

Post by redmondjp »

You should take Al up on his offer to rent his compression tester first, before pulling the head. Right now you need more information in order to figure out what is going on, and a compression test will certainly help.

If you have really low compression in one or more cylinders, it could be a ring issue (I'd WAG stuck rings, where the rings are gummed up and stuck into the pistons). And you may not be able to tell this by visual inspection when the head is off (unless it's REALLY bad and the piston has worn the cylinder bore on one side) unless you pop the pistons out (basically an in-chassis rebuild at that point).

I've been where you are at, except it was with a VW rabbit diesel. We had the head on and off three times (arrrgggh!), and we could have avoided two of the three if I had done a compression test before pulling the head the first time. My friend and I talked about it, but we convinced ourselves that "it was the head" and off we went!
1982 Datsun 720 King Cab, SD22, 86K miles (sold)
1981 Rabbit LS 4-door, 1.6D, 130K miles (sold)
1996 Passat TDI 4-door sedan, 197K miles
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asavage
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#15

Post by asavage »

I think that the four-squirts-of-oil-in-the-GP-holes would have overcome stuck rings -- at least, it has for me, more than twice. This is assuming that the cranking speed is OK (ie good battery and decent starter).
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