BJ73 3B - Stuttering and stalling on start up, running fine once going. (1 Viewer)

[tpcrane]

Hi All,

I have a 1985 BJ73 that is giving me (and my mechanic) quite a headache at the moment, hoping someone can help. I've driven it about 50000kms since I have had it with no issues at all.

I first noticed the car hesitating a little when first starting and getting going in low gears, once up and running it drove as always. This happened infrequently until one day it stalled while driving at low speed a couple minutes into a drive. It took a few cranks to get it started again but it drove fine after that. It was good for a week or so and then I noticed the similar stuttering again, it ran fine for about an hour and then I stopped for 30 minutes and it wouldn't start again. The next morning I hand primed the the engine, and bled the line through the air filter and then she started and drove without issue. I got it booked into the mechanic and he has had it starting and running without issue, until I go to pick it up. The same issue had occurred twice since, and he is holding onto it again and is wanting to change the glow plugs to see if that helps.

- I've noticed that the primer pump is pretty soft and leaks a bit when I hand pump it. Not sure if this could be the issue, however the mechanic doesn't seem concerned.
- The brake fluid was pretty low, however the mechanic has pressure tested and topped up without issue. I feel like this is most likely not connected, but thought mentioning as I've read somewhere while troubleshooting a person having a similar issue with brake fluid getting somewhere that it shouldn't.
- The mechanic has just completed a major service and everything is looking good.

I am really hoping someone out there has seen this issue and might be able to help. I am stumped and my mechanic doesn't seem sure what to do next either. Any thoughts or ideas will be much appreciated.

Thanks and talk soon,
Travis

 

[Behemoth60]

It's probably a fuel problem. It's almost always a fuel problem.
Start with the easy things... the fuel filter. Change that.
Is your truck infected? algae can grow in diesel fuel, and really screw with fuel systems. There's a treatment for that.
A leaking fuel pump could be the problem too, letting air in, but they are very reliable and rarely go.
I once had a partially clogged pickup in my fuel tank that was impeding flow of fuel. Truck would run fine for a while then sputter and stutter as it became starved for fuel. That was a hard one to diagnose. I blew compressed air backwards through the fuel line and into the tank and that cleared up that problem.

The other thing could be a failing hard line between the injector and injection pump. If it has a pinhole leak that is just developing and only occasionally leaking, that could explain it. There would be evidence of a leak somewhere though.
Could also be a problem with a clogged up fuel return rail, but that is a long shot.

If it starts and runs fine sometimes, then we can assume things like compression is good and injectors are good and the injection pump is all working. But if it is occasionally stuttering, but otherwise working, then there is something wrong in the fuel system.

 

[Behemoth60]

One other thought... it could be low oil pressure. There is a safety feature where low oil pressure signal will try to shut off the engine. However, there's this weird thing that sometimes happens when the oil pressure switch is right at the triggering oil pressure, the contacts kind of flutter and send intermittent signals to the EDIC to shut down the engine, which could cause a stuttering response. That's pretty easy to see though, as you can usually hear the EDIC relay fluttering and actually see the EDIC motor and actuator arm actually trying to turn off fuel to the injection pump.

 

[tpcrane]

Thanks for your thoughts Behemoth!

The car is with the mechanic and he has changed the fuel filter and sediment filter, neither were in particularly bad shape. Reading through some other threads I am starting to think it could be an issue with the diaphragm. I had noticed it starting to idle a little higher than normal, but hadn't joined the dots until reading other posts. Does this seem likely to you?

The mechanic has just done an oil change and tested pressures so I'd rue that out.

Also if the primer pump is dodgy would this lead to the issue? It is very soft to pump and spills a fair bit of diesel when I pump it. It pulls diesel through without an issue however with very few pumps.

I haven't checked the condition of the fuel tank but will ask the mechanic to take a look at that too while he has it.

Thanks again for your help. Much appreciated!

 

[ceebs87BJ]

If it's the original primer pump, I'd replace with an aftermarket Bosch one. Mine leaked, though the truck ran fine. They are like $40 and are a really easy swap.

 

[coldtaco]

your primer should not be leaking when you are priming, at least not around the body. don't know on a 3B but the 2H there is a bleeder at the fuel filter that I open when ever I need to use the primer pump.

 

[OGBeno]

your primer should not be leaking when you are priming, at least not around the body. don't know on a 3B but the 2H there is a bleeder at the fuel filter that I open when ever I need to use the primer pump.

The bleeder at the fuel filter is only applicable to B series engines with a Zexel inline pump. The rotary VE style pumps did not get this style fuel filter assembly.

 

[Irish11]

The bleeder at the fuel filter is only applicable to B series engines with a Zexel inline pump. The rotary VE style pumps did not get this style fuel filter assembly.

x2, and if its a 3bii with the rotary pump instead of the 3b with the inline pump, the primer is going to be on the top of the fuel filter built into the housing. If that is failing you need a new housing, or to rebuild the pump I believe.