3b diesel white smoke/misfire (1 Viewer)

[bj70cruzer]

I have a bj70 with a 3b diesel which has 505000km running 20psi of boost.

It always had alittle bit of white smoke on start up but wpuld clear up realy quick. But recently i have rebuild the injectors with new denso nozzles pop tested at 1650psi and good spray pattern.

After installing these new injectors the engine is very rough on first start up sounds like engine is missing and plumes of white smoke which is unburnt fuel.

It take about 5 mins of idling for the smoke to go away but theres still abit of a miss at idle which was never there before the injertor rebuild.

I have taken the injectors out and re tested the spray patrern and pressured and all seems good.

 

[gerg]

Have they been leak tested? Did you swap a different set of injectors in to see if the symptoms go away? Makes me wonder if your timing is being retarded by your pop pressure. The higher the pressure the more time it takes to crack the injector open and the more delayed the injection event is. Might want to try advancing your timing a tad. If your running that much boost spill timing it to get an accurate reading might be a good idea.

 

[gerg]

Are all your glow plugs good? If you have one bad one you might be seeing one cylinder not catching.

 

[bj70cruzer]

I had the exact same thoughts about the pressures effecting the timing but didnt think it would make such a drastic change.

And yes the glow plugs are brand new and they all heat up.

I glownit for 5 seconds and it starts straight away then starts running rough blowing white smoke.

 

[gerg]

Does smoke go away with more cow bell....erm I mean glow? I usually glow for 10 sec and give it a bit more after its started every now and then. Might be a combo of one cylinder lower on compression and retarded injection from new crack pressure. What's your injection marks set to? Pretty crude measurement but easy to check.

 

[NicaNorth]

I’ve experienced this very issue on one of my BJ70 LCs. Turned out to be a hair-line crack on the head, right at the third cylinder.

Mine was producing a good amount of white smoke and had a mis-fire/ staggering idle. It drove, but definitely lower on power than the usual (which isn’t much to begin).

My issue literally developed over night as the day before I drove it a good 70 miles (highway and backroads) without a hiccup.

How did yours run prior to the injectors being rebuilt?

 

[gerg]

Could check for bubbling in the radiator I guess. Never hurts to check that.

 

[roscoFJ73]

After installing these new injectors the engine is very rough on first start up sounds like engine is missing and plumes of white smoke which is unburnt fuel.

It can be a symptom of the injectors cracking too early. This means the fuel is going in before the air has been compressed to its optimum temperature and the fuel hits the cylinder walls. The white in the smoke is condensation.

 

[lumpy70]

White smoke is not enough fuel, adjust timing first ,then play with fuel

After my rebuild I had boatloads of white smoke until I adjusted timing ...problem solved

 

[gerg]

Wow lots of varying opinions here.

 

[lumpy70]

Yes, but timing takes literally minutes to adjust!

 

[gerg]

I agree on the timing, just not the white smoke and lack of fuel.

 

[bj70cruzer]

Ok so bit of an update.

I have done a compression test with the results below from cyl 1-4

400psi
380psi
320psi
300psi

Wet test
Last two cylinders

360psi
340psi

As we see the last two cylinders are low and theres a large variation between 400 and 300psi whic is what im asuming is giving the misfire sensation.

And yes i checked valve clearences and all are good.

Im thinking along the lines of what gerg mentions with the timing change due to higher pop pressure effecting the lower pressure cylinders.

I dont r ealy want to mess with the timing to try and cover up the issue so i will try to pour some solvent into the cylinders and see if its carbon in the ring land causing these issues if it dosnt help it will be getting a full rebuild.

I also think this may explain my bad fuel economy 15litres per 100km or around 550km max out of 90 litres of fuel.

 

[bj70cruzer]

I have a video of a cold start which i will upload once i figure out how to

 

[bj70cruzer]

So i had atf sitting in the cylinder overnight i cleared it all out and went for a drive came back let it cool down and compression is up now.

415psi
400psi
390psi
380psi

I did try another cold start still smoke allitle and slight miss but cleared up within 1minute compared to over 5minutes before and way less smoke.

I have put another round of atf in the cylinder this time mixed with acetone.

After this round if the compression is still good and it still smoke alittle i will spill time the pump and see what results iget.

So far it looks promesing...

 

[roscoFJ73]

White smoke is not enough fuel,

It can be, but it can also be from fuel that is burning at too lower temperature according to my diesel trainee text book

 

[brownbear]

I'm sure you are bleeding the injectors. But I have found the symptoms you are describing with air locks, and air issues on my injectors. They take a lot of bleeding while running.
I found mine engine running quite rough, bled them, and then had to do it again after a few drives. I found you need to bleed them multiple times. As the air circulates from the pump back to the injectors and around again.

 

[gerg]

Iv often found chronic air problems stem from that pesky short section of rubber hose at the rear of the head for the fuel return. If its old and no longer seals on the metal pipe the lift pump suction will pull small bits of air in. A simple 5 cent piece of hose can do you major headaches.

 

[bj70cruzer]

Since adding oil to the cylinders to free up the rings it no longer misfires just a constant white smoke kind of like a cold petrol car in the morning but alot less then before.

I will be checking timing tommorow aswell as air leaks.

 

[bj70cruzer]

So i did the timing check last week and it was dead on specifications at 14 degrees.

I still have the white smoke issue but not as bad as before.

One thing i did realise when i turn of the engine sometimes i get a high pitch squeel very faint.. im thinking it is sucking in air from somewhere but it dosnt last long maybe a few seconds so its very hard to pin point.

On previous suggestions i did replace the 5.5mm bleeder return line with new hose and clamps but that made no difference.

Also the primer pump plunger is abrand new bosch unit changed 2 weeks ago as the old one was leaking which made no difference either.

So far the only difference has come from the compression coming up abit.

Is there a good way to check for air leaks?
Iwas thinking to remove the line from the tank and pressurise the injector pump with say 10psi? From my compressor and see if i can get any air leak from anywhere?

Besides air leak causing issue im stumped.