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What causes 4JB1 Diesels to stop when cold ?

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What causes 4JB1 Diesels to stop when cold ?

Postby BalkaRoo » Sat Jul 18, 2015 6:38 pm

My old 2.8 Jackaroo has been running fine, but when the weather gets very cold (like it is now) it starts like normal and then after about a minute stops and has to be bled to get going again. I have read somewhere that its a common fault but I cant find the posts that deal with it, so does anyone know what causes it and is there anything that can be done to stop it happening ?

Thanks,
Graham
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BalkaRoo
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Vehicle: 1984 Jackaroo 2 Ltr
1988 Jackaroo 2.8 Ltr Diesel
1887 Jackaroo 2.2 Ltr Diesel

Re: What causes 4JB1 Diesels to stop when cold ?

Postby geeves » Sun Jul 19, 2015 7:09 am

what happens if you just try to restart?
How long is the glow timer glowing for? (this question is to gauge how cold is cold)
When you reprime how many pumps before it goes hard?
4jb1 is direct injection so starts easy but has a crude cold start setup. It temps between 5 and 10C its not unusual for it to start and stop almost straight away It takes a little throttle control to keep it going the first 10 seconds or so. Below 5C and the cold start system advances timing and sets the glow plugs to long glow (30 sec not .5) and it should start normally unless you are talking really cold My old bighorn wasnt bothered about stating with frost on the bonnet and a windscreen that froze back up in the time it took to wind up the hose
Things that cause grief in no particular order
Summer diesel I dont know the Aussi fuel settup but in NZ in winter the diesel sold south of Taupo in a low temperature formulation Quite a few Aucklanders have been caught out driveing down to the Ruapeahu ski fields then finding there car wont start in the morning. Standard advise is to refill as soon as you get there. This can also be a problem in a seldom used car (when did you last fill the tank)
Seals in the fuel filter housing. These are the 2 seals on the filter plus a few inside the primer
Loose or damaged fuel lines
Leaky seals in the injector pump
Inserting a length of clear hose into the fuel line at various places will show bubbles after any leak
Sanding your knuckles before starting work can help. That way you cant skin them
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Re: What causes 4JB1 Diesels to stop when cold ?

Postby BalkaRoo » Sun Jul 19, 2015 12:50 pm

G'day Allan,
It starts and runs fine "most" of the time, but when it fools around in cold weather it will start and you can drive it for about 300 yards after which it will start to falter. Sometimes you can catch it before you completely stop and fiddling with the accelerator eventually it will get its breath and start running properly, just like its pumping a small amount of air through the injection pump. I have checked all the seals and joints and they all "appear" to be ok because I had wondered if it had an air leak somewhere, but it only does it in low temperatures (3 degree or lower) and only when you start from dead cold . If you try to just restart it without bleeding the system it will crank until the battery is flat and as you have done 300 odd yards there should be plenty of heat in the engine to keep it running. As for how many "pumps" the priming handle takes, I gave up on trying to get the priming knob on the water trap to work years ago and carry a fuel pump off my old 2 litre petrol Jackaroo under the bonnet and hook that up to prime it when ever I need to. I fill up most weeks so it won't be waxy fuel and I do drive it quite a lot, I took it on an interstate trip back in April and it never missed a beat (it didn't make enough power but that's another story) It only takes about 5 seconds pumping to bring it back to life again but its very annoying especially in my good cloths.

I have read some postings several years ago that were talking about this problem but cant remember what the cause was and now can't find the relevant posts. I remember that one chap that had trouble on cold days with his was in Port Headland up in the North of West Oz and it would never get as cold in our North as it would in New Zealand so don't know what happens to cause it.

Graham

Editing thought.
The more I think about it the more I think it must be something to do with leaking a small amount of air in through somewhere, either the valves in the priming handle not holding the fuel up to the pump and letting a small amount of air into the pump housing through a dry seal or some such when gravity is trying to pull the fuel back to the tank, but "why" only when its cold. Its been doing this for about 5 years and will go all summer autumn and spring without missing a beat and then periodically on cold days in winter it will do it. Normal temperature days in winter don't worry it only cold ones.
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Vehicle: 1984 Jackaroo 2 Ltr
1988 Jackaroo 2.8 Ltr Diesel
1887 Jackaroo 2.2 Ltr Diesel

Re: What causes 4JB1 Diesels to stop when cold ?

Postby geeves » Sun Jul 19, 2015 3:53 pm

"North of West Oz and it would never get as cold in our North as it would in New Zealand so don't know what happens to cause it."
Funny you should say that. A longstanding member here recently posted a big doom and gloom message on Facebook about the weather in Brisbane where the temperature was going to dip down to 8C overnight. I posted the Wellington forecast for the same day which said we might reach 8. I didnt mention that on that day Wellington was one of the warmest places in NZ (Snow in CHCH and Dunedin on the ground that day but also in Wellington hill suburbs) He admitted that obviously Brisbaneites could be being a bit soft.
I would start by replacing the fuel line between the water separator and pump with clear plastic pvc pipe You should use fuel safe pipe but this is temporary so you can see any bubbles.Normal pvc is ok for a few days but now long runs. I did find a split starting in my hose at one filter change. It didnt leak at that point but this section of pipe is normally under vaccumm
Sanding your knuckles before starting work can help. That way you cant skin them
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Re: What causes 4JB1 Diesels to stop when cold ?

Postby BalkaRoo » Mon Jul 20, 2015 9:32 am

I think I might "bite the bullet" and not only replace the fuel line but also the priming handle ! Its always been a pain and I get sick of having to undo clips ect to bleed it, not that I have to do it all that often as I have never actually run it out of fuel, only bleed it to get over this problem.
I will let you know how I get on.
Graham
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BalkaRoo
Isuzu Baby
 
Posts: 46
Joined: Fri Feb 19, 2010 9:15 pm
Location: Quairading, Western Australia.
Age: 56
Country: Australia
City: Quairading
Vehicle: 1984 Jackaroo 2 Ltr
1988 Jackaroo 2.8 Ltr Diesel
1887 Jackaroo 2.2 Ltr Diesel

Re: What causes 4JB1 Diesels to stop when cold ?

Postby geeves » Mon Jul 20, 2015 3:13 pm

If the electric pump you have now is able to flow through you may be able to plumb it in permanently and wire to a button so when its cold you hold the button and when its warm the fuel just flows through
Sanding your knuckles before starting work can help. That way you cant skin them
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geeves
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Joined: Sun May 10, 2009 1:36 pm
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