Thread: An unadvisable diesel additive....

thanks for that info, tho Im more interested in the nozzles, his pumps got some very minor bluing and some scuffing on a couple of sleeves (replaced) but his injector nozzles look like theyve been finished with a bench grinder... We've rebuilt the injectors (no choice) But I dont want to put everything back together untill we have an idea as to whats caused it...

So far we've eliminated..

combustion pressure entering nozzle. (no carbon)
wrong needle/nozzle selection. (rebuilt last year from kits specified in manual)
Mechanical damage (no nozzle nut damage)
Incorrect crack pressure setting (crack pressure ok but bad pattern from wear)

Im not buying into the following as Id have expected the wear to be different across the injectors but they all look like the same kind of damage.

out of spec components
failure of a "weak" part
incorrect assembly of injector
partical contamination.

Even the fuel guru at work is at a loss to explain it other than extended running on the wrong fuel or lots of suspended water in the fuel.


Im open to guesses Daft, brilliant, in or outside the box left or right field...(insert metaphors here as you see fit)

One of our casual hire forklifts was blowing white smoke & not too healthy. I asked the apprentice if he'd put diesel in it. Hell no was his indignant reply. Next day I was checking off the job sheet & sure enough the diesel was booked to it - little $hit got a good flaming not for making a mistake but for lying about it. Once every 2 mths I get a call from a customer who has fueled onsite and done the same or vice-versa. One just on Friday.

Dan

Hi Dave,

Not able to get pics of injectors for you, but don't forget that Tdi ones are a throw away item and at least the toyota ones, especially the Diesel Kiki injectors/ nozzles are a good quality rebuildable unit.
If there is any doubt after startup, these are in the bin.

I pulled a Bosch Tdi one to bits to have a look see, and are very simple and being Bosch, of good quality. They just aren't serviceable. I have however seen some huge KM out of them, and they fail very infrequently. My Isuzu 4BD1 with a Diesel Kiki system has now topped 440,000km, and never had the injectors out. This is I know very neglectful on my part, but the previous owner of this ex county 110 engine had clocked up the first 410K always changed fuel filters every oil change, and had a decent sediment trap fitted. Look after diesel stuff and it should go for a LONG time.

JC

Originally Posted by Blknight.aus

thanks for that info, tho Im more interested in the nozzles, his pumps got some very minor bluing and some scuffing on a couple of sleeves (replaced) but his injector nozzles look like theyve been finished with a bench grinder... We've rebuilt the injectors (no choice) But I dont want to put everything back together untill we have an idea as to whats caused it...

So far we've eliminated..

combustion pressure entering nozzle. (no carbon)
wrong needle/nozzle selection. (rebuilt last year from kits specified in manual)
Mechanical damage (no nozzle nut damage)
Incorrect crack pressure setting (crack pressure ok but bad pattern from wear)

Im not buying into the following as Id have expected the wear to be different across the injectors but they all look like the same kind of damage.

out of spec components
failure of a "weak" part
incorrect assembly of injector
partical contamination.

Even the fuel guru at work is at a loss to explain it other than extended running on the wrong fuel or lots of suspended water in the fuel.


Im open to guesses Daft, brilliant, in or outside the box left or right field...(insert metaphors here as you see fit)

Daft suggestion No. 1

If it was running on a mixture, and obviously it was firing, does petrol burn at a higher temp than deisel (or the mixture of the two) causing the nozzles to 'melt'

I shall shut up now

maybe think of it this way too Dave, fuel gets injected into the precomps or cylinders ( H diesel or 1HZ) under huge pressures, this is enough to actually wear away the nozzle tips over time, effectively eroding them away. If the fuelling has been wound up also, the combustion temps can be enough to cause tip damage. ( unlikely in non turbo engines though) How old are the injectors, and what series toyo engine is it?

JC

pulled a Bosch Tdi one to bits to have a look see, and are very simple and being Bosch, of good quality. They just aren't serviceable. I have however seen some huge KM out of them, and they fail very infrequently

Justin how do the nozzles look with big miles on them ?
I know it's impossible to check the second stage on these, but I'm wondering how far the crack pressures had dropped with big milages on them ?
Have seriously been considering swapping out the injectors on mine (200,000+km) based purely on the km.

Am getting some Patrol ones rebuilt soon (225,000km) and we are increasing (doubling) the OE crack pressure. I asked the shop about increasing them and by how much and their standard rebuild is to double the crack pressure

Interesting thought Rick, crack pressures are really also dependent on pump condition also I would've thought, I can see the atomisation and pattern advantages in increasing this, but the pump also needs to be in good nick too. More pressure also means more wear on the tips, as I mentioned, over long periods they will actually wear away.
What has always been a good indicator for me, and this has been my experience, not science, is that if a Tdi will start quickly and evenly from cold, will use betwen 10 and 13 L/100km of diesel, doesen't blow excessive light coloured (not necessarily black) smoke and produces good power, then generallly I wouldn't recommend an injector change. Obviously at reasonably high Km if you are embarking on a significant trip, fitting new injectors before you leave can be good insurance if you are worried about having to get one in a hurry and paying through the nose...But I haven't struck this problem yet. I have a customer who has serviced his disco regularly and thoroughly, and after 420,oookm still has excellent fuel economy, 9.5 to 10.5 L/100, has heaps of power, and starts/ runs like the day he bought it in 1994.
Its really up to you, but if there is nothing wrong with their operation at the moment, leave well enough alone I say. I have been able to get them for about $220 each locally, 300 Tdi models.

Hope this will help

JC

umm isnt crack pressure set buy the spring that pushes the nozzle needle back into its seat?

I have no idea about what engine it is... its a 4.2l non turbo unit and it was rebuilt/overhauled less than 12 months ago and hasnt been used hard since.

There is no damage external to the nozzle but the needle and seat both look like something Id expect to find on a welding bench...

From the condition of the top half of the injector Im confident he hasnt been ripped by the blokes who did them for him (he prebought all the parts for total rebuilds) and paid to have them rebuilt.

The bluing in the pump is telling me its had something amis lube wise. The only thing I can think of is that the wife has screwed the pooch and that the mix was good enough to save the pump from damage but the extra heat in the combustion chamber has pushed the temp of the nozzle too high, destroyed the lubericating properties of the fuel and the injectors have ground themselvse internally....

Fuel guru at work is saying that its unlikely as there isnt enough damage to the pump or the top of the injectors.

We've just about got it wrapped but I dont want to run it up without being able to say with confidence "Thus is the cause" Hes not in a hurry for it, hes enjoying the fuel savings hes getting from being car pooled to work...