3B Diesel running rough on idle

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MarzBj42LX

MarzBj42LX

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Hi all, I posted this same thread in a different section, so thought I’d post it in this section for some assistance.
My bj42 3b diesel is running really rough on idle...basically when I’m at a red light the car vibrates a lot. I know these cars do vibrate a little being a diesel but this is noticeably not normal...though it smoothes out when I take off and revs are up. It’s currently idling around 650-700. Also notice it a little more sluggish than usual.
All thoughts and advice is welcome. That’s all.
 
OTBT

OTBT

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Sounds like its not running on all four - have you changed fuel filters or had bad fuel in the last little while ?

My suggestion is that you disconnect the fuel lines as if you would be bleeding the air out of the system and check how much comes out of each line when you crank the starter (make sure you remove the glow plugs first).
 
GTSSportCoupe

GTSSportCoupe

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Things I'd check are:

- Air leaks into the injection system
- Injectors worn out and out of balance (shows up at idle mostly in my experience)
- Compression issues related to engine wear or maybe a head gasket failure

If it fires up fine when cold, it's unlikely to be an air problem.
 
MarzBj42LX

MarzBj42LX

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Hey guys thanks for the advice...This is my first diesel and first bj42(3b) so I’m not very familiar with all these things. I ended up taking it to a place in Melb called Turbo Engineering apparently they know their stuff, I pick it up tomorrow and will let you know what the outcome is 😬 fingers crossed nothing bad.

I’m also enquiring about them putting a turbo on it for a bit more get up and go. But I’ve heard mixed reviews...what do you think?
 
plink01

plink01

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Is that the turbo shop in Thomastown?? I always heard mixed reviews from that place.
They did talk me out or turbo'ing my 2H 75 series landcruiser which I thought was pretty impressive. I had saved the money and was ready to have them do it but they talked some sense in to me.

I have a bj42lx as well and I personally wouldn't turbo it, you hear a lot of horror stories. If you ran low boost im sure it would be fine. But then it sort of defeats the purpose of turboing it in the first place if its gonna make little difference.
The LX is pretty rare as well, if yours is original I would be pretty hesitant to start modifying it. I love the 3B. It's really smooth for a little diesel and makes enough power for me off road. It's like a little tractor and I think that's what makes it awesome.
Hopefully you just have air in the system and it's just not firing properly.
 
lowenbrau

lowenbrau

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A few things...
  • The scavenger line is prone to cracking and letting air into the system.
  • Valves need to be adjusted periodically
  • IP diaphragm is a mtc item, most people forget.
  • Water separator can crack in cold weather, if not drained and let air in.
 
MarzBj42LX

MarzBj42LX

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Is that the turbo shop in Thomastown?? I always heard mixed reviews from that place.
They did talk me out or turbo'ing my 2H 75 series landcruiser which I thought was pretty impressive. I had saved the money and was ready to have them do it but they talked some sense in to me.

I have a bj42lx as well and I personally wouldn't turbo it, you hear a lot of horror stories. If you ran low boost im sure it would be fine. But then it sort of defeats the purpose of turboing it in the first place if its gonna make little difference.
The LX is pretty rare as well, if yours is original I would be pretty hesitant to start modifying it. I love the 3B. It's really smooth for a little diesel and makes enough power for me off road. It's like a little tractor and I think that's what makes it awesome.
Hopefully you just have air in the system and it's just not firing properly.
Hey mate..thanks for the reply. Yeah I’ll soon find out what they are like. They seem pretty knowledgeable...but you know what it’s like, they all trying to make a dollar.
Oh nice..yeah I have two of them and both original..one is a 83 and I’m in the middle of restoring , but I came across this 82 model which is pretty clean and just going to use it for touring and camping..so just gonna keep it as it is. I just got the dyno report and apparently it’s only making 23kw to the wheels lol. I know they are sluggish but didn’t know it was that bad. I wonder what could be wrong 🤔..they were meant to do a health check and didn’t even check compression. A little annoyed. All they did was a dyno.
 
plink01

plink01

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Haha 23kw is a bit s***. Going off my poster it should have 63kw at the crank. So take off 15% for driveline loss and you should have about 53kw at the wheels if everything is working well. Your running at less than half it's total power.

I rekon your not running on all 4 cylinders. I'd start by replacing all hoses in the fuel system that look old and bleed the whole fuel system. If the manual fuel hand pump looks old replace that as well.
Check and clean out the sedimenter.

That's pretty easy and cheap and would explain why it's running so slow. If its getting fuel to all 4 cylinders as intended and still running like ass then things will start getting more serious.

That's pretty ordinary they didn't check anything else out while the car was there. Like it's pretty obvious it's running like s***, you don't need a dyno to tell you that!

20211125 175506
 
MarzBj42LX

MarzBj42LX

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Haha 23kw is a bit s***. Going off my poster it should have 63kw at the crank. So take off 15% for driveline loss and you should have about 53kw at the wheels if everything is working well. Your running at less than half it's total power.

I rekon your not running on all 4 cylinders. I'd start by replacing all hoses in the fuel system that look old and bleed the whole fuel system. If the manual fuel hand pump looks old replace that as well.
Check and clean out the sedimenter.

That's pretty easy and cheap and would explain why it's running so slow. If its getting fuel to all 4 cylinders as intended and still running like ass then things will start getting more serious.

That's pretty ordinary they didn't check anything else out while the car was there. Like it's pretty obvious it's running like s***, you don't need a dyno to tell you that!

View attachment 2847672
Haha yeah that’s what I thought. So just got it back from a fuel specialist and injectors where terrible so got a new set put in, also hd the valve clearance reset. He did a compression test and these are the results:
Cyl 1 = 370psi
Cyl 2 = 350psi
Cyl 3 = 320psi
Cyl 4 = 350psi

Sooo any advice on this? I know it’s not a brand you car but is this ok considering the age? Or what should acceptable compression be?
 
GTSSportCoupe

GTSSportCoupe

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Haha yeah that’s what I thought. So just got it back from a fuel specialist and injectors where terrible so got a new set put in, also hd the valve clearance reset. He did a compression test and these are the results:
Cyl 1 = 370psi
Cyl 2 = 350psi
Cyl 3 = 320psi
Cyl 4 = 350psi

Sooo any advice on this? I know it’s not a brand you car but is this ok considering the age? Or what should acceptable compression be?

Testers can vary a bit. Your numbers are expected for a tired 3b, but it's good they are even. But honestly, if it starts clean/easy, and idles smooth now, I would just keep running it. How is the blow-by on it?
 
lowenbrau

lowenbrau

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Haha yeah that’s what I thought. So just got it back from a fuel specialist and injectors where terrible so got a new set put in, also hd the valve clearance reset. He did a compression test and these are the results:
Cyl 1 = 370psi
Cyl 2 = 350psi
Cyl 3 = 320psi
Cyl 4 = 350psi

Sooo any advice on this? I know it’s not a brand you car but is this ok considering the age? Or what should acceptable compression be?
I trust that was measured hot and after the valve-set? If so then it isn't ideal (ie over 425) but well about the recommendation for rebuild. (sub 300) How is the power now? Any significant tailpipe smoke?
 
MarzBj42LX

MarzBj42LX

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Testers can vary a bit. Your numbers are expected for a tired 3b, but it's good they are even. But honestly, if it starts clean/easy, and idles smooth now, I would just keep running it. How is the blow-by on it?
Well it always started perfectly, it seems to run a little better now they have done the injectors, though it’s still idling slightly rough..it’s strange..when I touch the accelerator a tiny bit it smooths out. And it still lacks a bit of power when going up hill. In terms of blow by...there’s no smoke at all from exhaust or the crank case breAther under the car...though I drove it about 60k’s today and when it was hot there was some smoke comming out of the breather. So not sure if that’s normal.
 
MarzBj42LX

MarzBj42LX

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I trust that was measured hot and after the valve-set? If so then it isn't ideal (ie over 425) but well about the recommendation for rebuild. (sub 300) How is the power now? Any significant tailpipe smoke?
I think they did it when it was cold in the morning. Power is slightly better but still struggles a bit going up hill. No smoke at all from exhaust not even under load. Pretty clean
 
lowenbrau

lowenbrau

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I think they did it when it was cold in the morning. Power is slightly better but still struggles a bit going up hill. No smoke at all from exhaust not even under load. Pretty clean
I think it's probably fine for its age. Even in the 80s when a Corvette had less than 200HP they were pretty slow. If it was me I'd bump up the fuel a bit until the tailpipe smokes a little under max throttle.

I forgot to ask if the air filter was clean.
 
MarzBj42LX

MarzBj42LX

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I think it's probably fine for its age. Even in the 80s when a Corvette had less than 200HP they were pretty slow. If it was me I'd bump up the fuel a bit until the tailpipe smokes a little under max throttle.

I forgot to ask if the air filter was clean.
Yeah maybe I’m just not familiar with this engine or car to know what they are meant to be like. Yeah air filter looks pretty clean..I might just give it a full service and see how it goes..maybe I’ll up the idle a little too. Is the engine breather meant to blow a little smoke when she’s hot?
Also if anyone is in Victoria and knows these cars I’m happy to pay to come check it out. I need someone that’s use to this car/engine.
 
lowenbrau

lowenbrau

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A little blowby and a few drips of oil from the tube are normal. There are 147 places named Victoria and at least one person in this thread is from near Victoria BC Canada. With the cost of diesel, you’d best be specific. :flipoff2:
 
MarzBj42LX

MarzBj42LX

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A little blowby and a few drips of oil from the tube are normal. There are 147 places named Victoria and at least one person in this thread is from near Victoria BC Canada. With the cost of diesel, you’d best be specific. :flipoff2:
Ok well I guess its normal then.
Haha lol...Australia, Melbourne, Victoria.
 
plink01

plink01

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I live in East Gippsland if you wanna come up and test drive one.
There is definitely something wrong with it. The 3b definitely isn't fast but it moves along a bit quicker than most people expect.
 
MarzBj42LX

MarzBj42LX

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I live in East Gippsland if you wanna come up and test drive one.
There is definitely something wrong with it. The 3b definitely isn't fast but it moves along a bit quicker than most people expect.
That would be amazing..maybe I’ll drive my one up and you could check it out and see what you think. This is my mobile 0402777054..feel free to text me.
 

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