* Cold Weather Starting Difficulty *

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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asavage
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* Cold Weather Starting Difficulty *

#1

Post by asavage » 14 years ago

EvergreenSD wrote: This concern is being forced onto the back burner by another problem. The cooler weather here has resurrected my cold-starting woes with a pronounced miss and a bunch of smoke.
If it runs OK after a minute or so, that's usually GP or GP system related, not injectors. A lot has been written about that here.
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.

EvergreenSD
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#2

Post by EvergreenSD » 14 years ago

I have already replaced the Glow plugs and checked the voltage supplied. I really think that they are working since the engine always lights right off when they are warm, it just misses while it tries to warm up. This definitely lasts longer than a minute if it is cold out. My theory is that it is an injector that no longer sprays a decent pattern when the fuel is cold. I think I 'm going to pull the injectors to see what they look like. I've definitely been wrong before . . .
'82 SD22 720 Kingcab with flatbed

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#3

Post by asavage » 14 years ago

EvergreenSD wrote:I have already replaced the Glow plugs and checked the voltage supplied. I really think that they are working since the engine always lights right off when they are warm . . .
Are the glows staying energized long enough? On a 45° morning,

Image

The dash Glow light goes out when -minimum- glow time has been met. This is an estimate based on coolant temperature. The Type I system glow plugs take about 15-20 seconds minimum glow time regardless of engine temperature. It's just that with a warm engine, the glow plug is not the only source of heat in the combustion chamber. The glows stay ON until you hear the duty solenoid "thunk" OFF some 10-30 seconds later depending on coolant temperature.

Twenty seconds is a long time, when you're sitting in a cold cab and want to be somewhere else.
Last edited by asavage 12 years ago, edited 2 times in total.
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.

EvergreenSD
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#4

Post by EvergreenSD » 14 years ago

I don't think that I explained myself very well in the last post. Given the way it is tempermental in cooler temps, I wait for the GP to cycle off on a cold start, then turn the key off and back on to start. You're right it does seem like a long time but I have definitely been waiting for longer than 20 seconds, more like a minute. Also, what I meant to say is that after the plugs are warmed the engine starts immediately on the first couple of cranks, then it settles into a rough idle with a pronounced miss. Also, the miss persists after the plugs cycle off sometimes.
'82 SD22 720 Kingcab with flatbed

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#5

Post by moose60 » 14 years ago

I have very similar symptoms. When I have the time, I plan to inspect the afterglow system. My understanding is that it glows after startup for a period of time (30 sec? a minute?) to reduce smoke and smooth out cold starts. When the engine is COLD, I hear the afterglow relay click off one or two seconds after startup. When the engine is warm, and I let it idle slowly, I will not hear the relay 'clunk' for 15 to 30 seconds. I have cleaned the thermo switch that threads in to the thermostat housing, but with no change.
Good luck with yours Evergreen.
Byron

82 Datsun 720 KC SD22

MPG Machine

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asavage
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#6

Post by asavage » 14 years ago

EvergreenSD wrote:what I meant to say is that after the plugs are warmed the engine starts immediately on the first couple of cranks, then it settles into a rough idle with a pronounced miss.
That's air in the pressure lines or a bad injector, yup. Since injector overhaul is a scheduled maintenance kind of thing anyway, I agree that having them tested etc. is a good next step.
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.

EvergreenSD
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#7

Post by EvergreenSD » 14 years ago

Fortunately, my afterglow system seems to be consistent and functional as well, I would guess it clicks off after about 15-20 after starting. I would be happy to be talked out of an injector rebuild I can't really afford but I kind of feel like I've been through everything else: new GP's, adjusted valve lash, new filters and fuel lines etc . . .
Does nobody like me theory that one or more injectors is spraying a mariginal pattern that doesn't burn adequately until the engine warms up? Also remember that I'm not getting the most phenomenal mileage either (about 32 on the last long trip).
'82 SD22 720 Kingcab with flatbed

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#8

Post by zen » 14 years ago

ok..

i have had cured this problem on my sd33..(inlne kiki bosh mz rbd pump)i will give details of what i did,and hopefuly it will be of some use to you..??

IF THIS IS COLD WEATHER related only and not all the time then...

its unlikey to be air in fuel..would do it all the time..

check if not replace glow plugs..just take them out and wire them across a battery and see what happens..beware they reach nearly 1000 degrees C in 15 seconds ... a bright orange/yellow glow so dont touch then! Dooh :wink:

check injectors..at a pump shop..(unlikley but well worth doing anyway,get them serviced at same time)

but formost check ip timing..mine was as simple as needing a slight tweek on pump ADVANCE it a degree or two..mine acording to lines on pump was correct,but on advancing almost completly removed start up smoke(none at all on first start up above 0c (32f)1-5 secs below it(and hardly visable)
miss fire removed...

hope this helps..do ip first cos it costs nothing..

oh could be low compression,but we dont want to go there :cry:
turbo it

(sd33t home turbo set up if anyone is interested..)

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#9

Post by asavage » 14 years ago

zen wrote:check if not replace glow plugs..just take them out and wire them across a battery and see what happens..beware they get f***ing hot, infact the glow.so dont touch them..dooh

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#10

Post by philip » 14 years ago

A little earlier in this thread, Al provided a scan from the FSM showing how temperature affects the AutoAfter Glow timer.

NOTICE the word "minimum" is used twice in that image. BUT ... what is not mentioned is that when the dash light goes out, the glow plugs are still ON until ... the duty relay under the hood goes "CLUNK."

I did not find a distinction between California vs. "Non-CA" AutoAfterGlow timers (surely that could be an undocumented CA concession for smog) but mine (CA model) does not discontinue operation above 140 degrees F as is shown on the chart. With a hot engine, the dash light goes out after 5 seconds but the glow plug duty relay stays ON for 30 seconds if you care to wait it out before starting.

AND, the glow plugs are run for an additional 30 seconds after the engine is running regardless of engine temperature.

Glow Plug Experience
Combustion Cackle with Cold Engine

Image
Last edited by philip 14 years ago, edited 2 times in total.
-Philip
Passed 08May2008
My friend, you are missed . . .

1982 Datsun 720KC SD-22

"Im slow and I'm ahead of you"

zen
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#11

Post by zen » 14 years ago

asavage wrote:
zen wrote:check if not replace glow plugs..just take them out and wire them across a battery and see what happens..beware they get f***ing hot, infact the glow.so dont touch them..dooh

and you have SEEN them working?? cos i have replaced glow plugs before,to still have probs..reason faulty new glow plug...

so it dont hurt(unless your me) to check em..does it?? :wink:
turbo it

(sd33t home turbo set up if anyone is interested..)

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#12

Post by philip » 14 years ago

zen wrote: And you have SEEN them working?? cos i have replaced glow plugs before,to still have probs..reason faulty new glow plug...

so it dont hurt(unless your me) to check em..does it?? :wink:
IF by chance glow plugs for the Type II AutoAfter Glow system are used in the Type I AutoAfter Glow system, the Type I system will keep them ON at full system voltage much longer than the Type II glows are designed for so .... early failures.
-Philip
Passed 08May2008
My friend, you are missed . . .

1982 Datsun 720KC SD-22

"Im slow and I'm ahead of you"

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#13

Post by Knucklehead » 14 years ago

I think I 'm going to pull the injectors to see what they look like.
Please let it be clear for posterity and the uninitiated that when we say "see", we mean see the spray pattern. Wasted injectors can still pass visual inspection. These things defy eyeball engineering. A bench test should cost nothing, takes less than a minute per injector, and you get to watch!
'82 standard cab 3 axle SD22 turbo
'89 int'l 9700 Cummins 444 (855 ci)
'29 HD FD export model

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#14

Post by EvergreenSD » 14 years ago

But if they look bad they are bad, right? I spoke with a person at the diesel injection shop and asked about testing and he told me to just check the nozzles for signs of wear. Maybe he just didn't want to volunteer to bench test?

Is there anything I need to know before pulling an injector or two? We are down to one car now so having the injectors done will mean downtime. Will I be able to reuse the sealing washers for a short time if I pull them to have a look and then need to drive somewhere?
'82 SD22 720 Kingcab with flatbed

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#15

Post by philip » 14 years ago

EvergreenSD wrote:But if they look bad they are bad, right? I spoke with a person at the diesel injection shop and asked about testing and he told me to just check the nozzles for signs of wear. Maybe he just didn't want to volunteer to bench test?
There is no short cut here. The "wear" or "damage" is NOT visible until you completely disassemble the injector and ... remove the pintle valve from the nozzle and examine the pintle under high magnification.

Fuel Injectors
EvergreenSD wrote:Is there anything I need to know before pulling an injector or two? We are down to one car now so having the injectors done will mean downtime. Will I be able to reuse the sealing washers for a short time if I pull them to have a look and then need to drive somewhere?
The above link has all that information. Your rebuilder needs to supply those nozzel tip sealing washers. Use ONLY the tip washer ... the ones you dug out of the head. Yes, digging the original flat copper washers out of the head is a pain. The FSM requires replacement everytime injectors are removed. You could ask for the SD25 style crush washers. Again, refer to the above link.
-Philip
Passed 08May2008
My friend, you are missed . . .

1982 Datsun 720KC SD-22

"Im slow and I'm ahead of you"

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