Bj73 3b cranking won't start (2 Viewers)

[Newzealandbj]

Hi Guys I am reaching here as I'm a bit lost.

I have a 1986 3b-II BJ73 255,000ks

Just have problems with it cranking and won't start, need to put a little brake cleaner in the intake just to get it to fire, which is far from ideal

Just replaced glow computer, 15second glow, glow plugs all good, new primer and just replaced seals on diesel injection pump as was leaking diesel when cold

First thing in the morning it will just crank and crank and won't fire. Once started and warm it runs like a dream until the next morning when it is cold..

I'm so stumped

 

[Squash]

Either fuel is leaking down overnight or you don't have good glow.
Check your primer in the morning, an airtight system will have almost immediate pressure, a leaky system will require some priming.
As for the glow system, you could try unplugging the temp sensor for the glow system. My 3b would easily start to -20C.

 

[Eurasiaoverland]

Have you checked that you're getting voltage at the plugs?

Running a clear fuel hoae from filter to pump will let you see if fuel is draining overnight.

If it's a 1986 engine it won't be a 3Bii, not that it makes any difference to the issue.

 

[CRZR45]

Make sure you replace or have new fuel lines. Mine had a pin hole leak on the return line at the back of the head and would loose pressure overnight. If your primer pump has to be pumped then you have air getting into the system. My2c good luck

 

[Tanner H]

Going to piggyback onto this topic as I'm running into the same issues and want to follow the outcome.

Question: will the hand pump start to get firm once pressure is achieved? the hand pump on my 13b-t has no change in firmness after about 30 or pumps.

My old 1hdt's primer got very firm once pressure was good, so im assuming i have some air in my current 13bt setup.

 

[coldtaco]

Going to piggyback onto this topic as I'm running into the same issues and want to follow the outcome.

Question: will the hand pump start to get firm once pressure is achieved? the hand pump on my 13b-t has no change in firmness after about 30 or pumps.

My old 1hdt's primer got very firm once pressure was good, so im assuming i have some air in my current 13bt setup.

Yeah the hand pump should get hard, but definitely before 30 pumps. How old is it? Might be a good time to change with a new Bosch unit

 

[Tanner H]

@coldtaco it has a Bosch on it I want to say from 2018/2019 maybe.

I eventually got it to firm up. I would do ten pump intervals, hold down, crack the bleeder on the filter and repeat. Did that maybe 5-6 times. I did hear air come out on the first couple bleeds. After it firmed up she fired up immediately and I ran a bunch of errands.

I can see some weeping at two injectors so I think I found my culprit.

 

[Squash]

Going to piggyback onto this topic as I'm running into the same issues and want to follow the outcome.

Question: will the hand pump start to get firm once pressure is achieved? the hand pump on my 13b-t has no change in firmness after about 30 or pumps.

My old 1hdt's primer got very firm once pressure was good, so im assuming i have some air in my current 13bt setup.

An airtight system will get tight within pumps!
30 is definitely a problem.

 

[Felde]

Any tiny leak in the fuel lines makes the fuel run back into the tank.
The feed line to the priming pump often has just enough fuel left to prime the fuel filter and IP. But on start, it just runs a few sec and dies, once the next bubble from the main line comes trough. And you repeat again ...
Most likely it is air in the main fuel line.
Disconnect the main fuel line from the priming pump inlet. Suck trough a gallon of fuel with an external pump, unless it runs free of bubbles.
It needs to be that much, because it's a long way to the tank ...
Reconnect without letting too much air in.
Prime fuel filter. Should fire right up.
You can also keep the bleeder open and use the priming pump. But that's very hard on the pump and it might start leaking. Also the flow is not high enough to really move the bubbles, so it takes even longer.
You can also just keep on starting the truck and prime in between. Eventually the duration of it running will increase. But that's hard on the engine components.
Just waiting a bit (or having a beer) might also help for the bubbles to unite and surface to the bleeder.
I have been there just 2 days ago.
Good Luck Ralf

 

[Tanner H]

OK back in here to see where I should start next.

went outside this morning to work. before i did anything, i popped the hood and felt the primer pump. It was firm already without even a single pump. ok sweet.

-started the truck up no problem. let it idle a bit.
-went to drive off and it died on me after a few feet.

-went to do the primer trick and would not get firmed up for the life of me. I must have pumped 100 times before I put my tail between my legs. (aftermarket pump, unsure if its bosch but has a black plastic cap)


Tomorrow I'm going to try and trouble shoot. let me know if what you guys think about this:

-buy transparent diesel-safe line
-run this from the inlet on the pump to a small jug with diesel
-prime the pump until firm


if this firms up quick...we can assume I have a bad line from the tank to the pump?


if this works, I will then replace all soft lines from tank to pump.



I believe the line circled in this photo is the line that comes from the tank, is this correct? If so, does anyone know the ID of the line? I would assume 8mm but maybe someone can confirm.

 

[Felde]

Hi
From what you describe: Definitely sir in the main feed line from the tank.
I'd agree to the approach .
Assumptions are correct.
Yes, fuelline on the 3B is 8mm.
If the pump was still firm and dry this morning, you can tick off the pump to be good (at least it was before your 100 strokes...).
You might want to check or replace the soft lines, and also the sedimenter (probably bypass it for the time being).
But there is unfortunately one suspect item that's notorious for leaking: The pickup pipe on the tank. It has a bend that has a tendency to rust a hole in it.

(Ask me how I know).
Unfortunately, that sucker is on top of the tank, so you would need to drop the tank ...
(Anyways a good opportunity to check & paint it.)
I'd recommend to first try replacing the soft lines. Use my method described above to bleed the line from the tank. This type drill pump...

If it then still fails, the pickup pipe would be my next move.
Good Luck Ralf

 

[Tanner H]

@Felde Thank you for your expertise.

I did buy an amazon electric pump with 8mm inlets to make sure it fits during the bleed process.

 

[LJRay]

…as someone who also replaced all 35-year old lines throughout, 3x pumps plus 2x filters and the pickup on an LJ, I feel your pain.

Bite the bullet to make your next 30-years a breeze, and replace it all from pickup to injection pump.