Bloody Hard start SD25

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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nissy720
Posts:7
Joined:12 years ago
Location:Perth, Western Australia
Bloody Hard start SD25

#1

Post by nissy720 » 12 years ago

hey all.

This morning it was 2-3 degrees here (Celsius) ... it took me probably about 30 tries before the car actually ran... it would start and run ONLY if i kept the key turned to ignition - the moment i let it go, it dies...

I checked the glow plugs - they are new and get power, im sure im getting fuel because there is some smoke from the exhaust when trying to start...

during normal time and normal temperature - its also not easy.. sometimes it will start on the 1st go, sometimes on the 3rd or 4th.

any ideas??
many thanks guys!
83 Nissan 720 SD25 Diesel 4x4 Dual Cab Ute
Twin tip baffled muffler | Wheel Arch Extensions | TJM Bull Bar | Spotties| Fibreglass Canopy | intermittent knock in engine bay - its a real 4x4 now...

rlaggren
Posts:541
Joined:13 years ago
Location:San Francisco

#2

Post by rlaggren » 12 years ago

> power to the glow plugs...

How do you know? All of them? Do they all get warm? How long do they "run"? Details, details, details.

Assuming the GP's are all good soldiers, Does it crank nice and fast?

Assuming it cranks OK, is the the compression good?

If I understand your post, you had to keep the starter cranking in order to keep the engine firing. That sounds like you were firing on one or at most two cylinders for several seconds. That sounds like bad GP's or bad compression in two or more cylinders, assuming fuel delivery is OK. Compression can go bad because of cylinder/ring wear or valve train wear amoung other problems. You do a very basic check of fuel delivery by cracking loose the nut at the injectors (one at a time) and seeing if fuel squirts out when cranking the engine; that will NOT tell you if the injector is bad.

The above is just a generic punch list to get the ball rolling, garnered from years of fixing my own car problems and, recently, from reviewing the extensive info found here; I don't own this type vehicle. Others with more direct experience will have better specific suggestions.

Rufus
82 Maxima wagon

nissy720
Posts:7
Joined:12 years ago
Location:Perth, Western Australia

#3

Post by nissy720 » 12 years ago

Hi Rufus,

Thanks for that!

I've got the problem sorted out yesterday. I dropped the car off at an auto electricians place on tuesday night so he's got a nice cold start on wednesday.

Faults found were the glow plug relay turning on and off intermittently and relay for the injectors/pump also intermittently on/off.

Both were bypassed and it cranks and starts on the first go :)

when i first tested the relay for the glow plugs it didn't show power, then when one auto electrician tested it - it had power - he said its fine. Obviously it was being temperamental and worked then.

I have a button on the dash now to press for 10-15 seconds - manual glow plug heater button...
83 Nissan 720 SD25 Diesel 4x4 Dual Cab Ute
Twin tip baffled muffler | Wheel Arch Extensions | TJM Bull Bar | Spotties| Fibreglass Canopy | intermittent knock in engine bay - its a real 4x4 now...

rlaggren
Posts:541
Joined:13 years ago
Location:San Francisco

#4

Post by rlaggren » 12 years ago

Good to hear the problem was peripheral. Be careful how long you hold the GP button cuz some GP's get damaged after 12-15 secs or so - depends on the vehicle and I'm afraid I can't tell what type you have.

Rufus
82 Maxima wagon

chrwei
Posts:13
Joined:12 years ago

#5

Post by chrwei » 12 years ago

how intermittently? could you see it with a volt meter?

I have similar symptoms on my SD22, was hard to start when 80-90 degrees out, easy to start when 95+, and nearly impossible now that it's below 70. Once started, it runs OK though. I test the plugs a couple months ago by following the FSM instructions they got bright red in the time stated in the manual. This was direct using a battery, so I guess the relay could be an issue, but I can hear it clunk on when starting and off after several seconds
1981 Datsun 720KC SD22

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asavage
Site Admin
Posts:5351
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Location:Duvall, Wash.
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#6

Post by asavage » 12 years ago

The SD25 has a different glow control system, different glow plugs, and different IP (and has an IP fuel cut solenoid) than your SD22.

For the SD22, look closely at the fusible link on the battery terminal that feeds teh GP relay, it is very troublesome, as are the (three?) oversize spade terminals on that bus feed. This is covered very well in another thread.
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.

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