1hd t smokes at idle

[Jason Read]

Hello, My 1992 80 series with 1hd t smokes at idle. There is not much at all once warm but when it idles from cold its really smokey. It is fuel not oil going by the smell. Engine starts like a switch! No starting issues at all, misses and farts for 3-4 seconds then runs fine. Does not blow much black smoke and burns about 1/2 litre of oil between changes. Oil stays clean for a few thousand ks after an oil change. Does not fume at all from the oil cap and very little if you remove the breather hose. I have thought about changing the glow plugs a the previous owner gave me a set but had heard that they don't really need them! Could it be the 2 stage injectors? Thanks

 

[AndycruiserguyLomas]

Have the injectors overhauled. I did mine at 150K and it certainly made a difference at tickover then cold. ( same engine).

 

[StarCruiser]

As above but also check valve clearances and if it doesn’t correct it consider looking at your delivery valves.

Does it get a little lumpy around 900 rpm?

 

[Dave2000]

Before doing anything have you removed the ACSD? If so your injection timing will be wrong for a cold engine, the fact it clears when warm this may be the cause?

Mine does the same for a mile or two, over 260,000 miles on injectors thus far, passed MOT smoke and emissions three days ago.

Regards

Dave

 

[Mike Clark]

Hello, My 1992 80 series with 1hd t smokes at idle. There is not much at all once warm but when it idles from cold its really smokey. It is fuel not oil going by the smell. Engine starts like a switch! No starting issues at all, misses and farts for 3-4 seconds then runs fine. Does not blow much black smoke and burns about 1/2 litre of oil between changes. Oil stays clean for a few thousand ks after an oil change. Does not fume at all from the oil cap and very little if you remove the breather hose. I have thought about changing the glow plugs a the previous owner gave me a set but had heard that they don't really need them! Could it be the 2 stage injectors? Thanks

Hi Jason how did you get on identifying this problem as mine does this also. It uses no oil but blue smoke at idle and puff when taking off but looks clean enough when driving as like yours I'm guessing

Thanks Mike

 

[frank rabbets]

Unburnt fuel is almost defo injection timing retarded.

 

[Grimbo]

If the glow plugs come out OK then change them .....although both the 12 V and 24v engines will start without heat either from glow plugs or in the 1HD FT case the grid heater certainly the 24V keeps the grid energised for a good time after start to help stop exactly what you are seeing ........it may even use the water temp sender for info .

I get involved with a lot of diesels that use mechanical injection and also remember them when they were new in the 90's .Most are 8 litres plus but the same apply s.

They all smoked when cold.......even with a cold start device of varying types fitted that would alter injection timing..... a cold start particularly in the winter was blue smokey for a bit .
If it stops when the temp gauge starts to move off it's stop and certainly when it's up to temp then nothing wrong with it .
It's got a big cold engine block to warm up and what you are seeing is unburnt fuel because the combustion chambers are not warm enough yet

Enjoy the fact you have a proper engine that will outlast most common rail engines .
Modern diesels run so clean and quiet that we tend to forget an 80 series engine is 1970/1980's tech and as such is set up to run at it's best when at correct running temp ( a good reason to never just remove the thermostat if it fails)

Bung a high dose of proper injector cleaner in the tank ( even remove the fuel filter and fill it with neat cleaner before refitting ) and then go and drive it like you stole it for an hour before you take injectors out or worry about anything else......it's probably fine .

 

[StarCruiser]

@Grimbo , have you got any idea why mine is a little lumpy just up from idle, worse cold and worse with the auto box in gear, but goes like a train once it’s going? I’ve had injectors out and refurbed and there’s no engine mount issue or balancer. Valves are a tiny bit out but not much. Compression is all good within 20 psi. Does it hot or cold.

 

[Grimbo]

@Grimbo , have you got any idea why mine is a little lumpy just up from idle, worse cold and worse with the auto box in gear, but goes like a train once it’s going? I’ve had injectors out and refurbed and there’s no engine mount issue or balancer. Valves are a tiny bit out but not much. Compression is all good within 20 psi. Does it hot or cold.

Only things I can think of are -

The injection pump is a little worn so at low idle and under load it's uneven . A pusher pump can help and would be my first option before a pump rebuild . (Try feeding the pump from a can mounted well above the pump ....ie roof height ....see if that makes any difference......if so then pusher pump should sort it) although this is only masking the original wear but may well do so for many years .

Slightly pitted or worn valve seat . ( would have thought comp test would show this though )

Auto box in gear is just putting the engine under a little more load so shows the symptom more.

On your engine it's easy to undo each pipe at the injector one at a time @ tickover and see if any one injector has less of an affect on the engine .....this could at least show you which cylinder is slightly lazy @ tickover .....maybe this is the one down 20 psi .

 

[StarCruiser]

Thanks for this Grimbo. A while back I teed into the main fuel line for an Eberspacher heater I’m beginning to think that may have something to do with it despite having a shut off valve in Line.

I did try cracking each injector but the engine just seemed equally (very) lumpy with each one I undid.

The other suspect was pump Delivery valves. Thinking if one lets by a tiny bit it would give a slight delay to injection timing but not show at higher revs. Coupled with Toyota saying in the FSM ‘the pump won’t give trouble but any issues could be Delivery valves’ or something like.

I’ll try the can first.
Pressures were
520
480
480
480
490
500
It wasn’t especially hot when I did it which could have skewed the readings.

 

[frank rabbets]

The old diesels do have auto advance to burn the fuel at cold temperatures but they are only partially effective so they smoke whatever.