potential death rattle

Update in case anyone is following this for info: all 8 injectors out and I just wanted to add a tip for anyone who has struggled to get these things out.

I did this with both engines cold and without using any of the specialist tools you can buy. However, what I did use was something not related to car mechanics at all - a stone carving gouge chisel. This is a forged chisel with a scoop or curved profile and it just happened to sit perfectly under the arm of the injector that connects to the common rail. The base of it is smooth and broad enough to be levered against the casing without damaging it, while the rounded upper part sits perfectly under the injector arm. It's made to take persistent punishment as it is hammered into stone, so strong enough for this job anyway.
First I undid the nuts holding collar down.
Then I got another flat stone chisel to begin the process of levering the injector from side to side. Once that was loose enough to turn by hand I got the gouge profile in place and gently began to lever the injectors out. Doing it this way even the two that were really not keen on coming out eventually did.

The most force I used was a couple of light taps on the chisel shaft for the two most reluctant injectors.

Both vehicles 20 years old, so those injectors had been in there for quite a while.

Also, two of the injectors on my daily - the one having the problems Im trying to resolve - had the 0 rings missing from them. The well where these two were seated were full of crap. I thought maybe the 0 rings had disintegrated or broken off and fallen in, but there's no sign of them down there.

Obviously they are there for a reason and I'm wondering what sort of difference not have them in place would make.

Well, they needed doing. Remains to be seen whether it was a good idea to do it this way because the parts are still soaking.

I took the ends of the injectors to bits and blew carb cleaner through the nozzle. Numbers two and four were blocked pretty badly.

Then I soaked them for around an hour (not timing it) in a mix of carb cleaner and diesel. Then I blew them through again and got a much better spray pattern. Still not spot on on two and four so have put back into soak in a mix of injector cleaner and diesel. There were black bits in the solution after only an hour.

TBH I wasn't sure diesel and carb cleaner was a good idea (just what I had to hand), so opted for the injector cleaner in the mix for second soak.

MGT said:

I thought maybe the 0 rings had disintegrated or broken off and fallen in, but there's no sign of them down there.
Obviously they are there for a reason and I'm wondering what sort of difference not have them in place would make.

Click to expand...

~~~~~~~
from ..
https://www.yourmechanic.com/article/how-to-replace-fuel-injector-o-rings-by-marvin-sunderland

''
Fuel systems are always maintained under pressure whether the engine is running or not. The O-rings on injectors are designed to seal all fuel and fuel vapors from escaping into the engine compartment. These rings are made of a type of rubber that is petroleum and hydrocarbon resistant.

It is very important to have an effective O-ring that can seal fuel vapors in and keep them from escaping. The exhaust temperature on the exhaust manifold where it connects to the cylinder head can reach temperatures up to 1,250 degrees fahrenheit. Fuel vapors will ignite at a minimum temperature of 850 degrees fahrenheit. If the vapors were to come in contact with the manifolds with a temperature of 850 degrees fahrenheit or higher, the fuel vapors will ignite.

The O-rings for fuel injectors are designed to hold pressures up to 750 pounds per square inch (psi). Most fuel operating systems have between 60 psi to 125 psi while the engine is running.
"
~~~
( that were 1st on google search .. "why do diesel injectors have o rings" )
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Here is a link to injector removal and disassembly. I didn't;t do the engine warming thing but the rest is very useful for the cleaning and taking to bits.


Especially useful if you take it to bits then notice a really tiny small washer thing and wonder where it is supposed to go.

hd3 said:

~~~~~~~
from ..
https://www.yourmechanic.com/article/how-to-replace-fuel-injector-o-rings-by-marvin-sunderland

''
Fuel systems are always maintained under pressure whether the engine is running or not. The O-rings on injectors are designed to seal all fuel and fuel vapors from escaping into the engine compartment. These rings are made of a type of rubber that is petroleum and hydrocarbon resistant.

It is very important to have an effective O-ring that can seal fuel vapors in and keep them from escaping. The exhaust temperature on the exhaust manifold where it connects to the cylinder head can reach temperatures up to 1,250 degrees fahrenheit. Fuel vapors will ignite at a minimum temperature of 850 degrees fahrenheit. If the vapors were to come in contact with the manifolds with a temperature of 850 degrees fahrenheit or higher, the fuel vapors will ignite.

The O-rings for fuel injectors are designed to hold pressures up to 750 pounds per square inch (psi). Most fuel operating systems have between 60 psi to 125 psi while the engine is running.
"
~~~
( that were 1st on google search .. "why do diesel injectors have o rings" )
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Click to expand...

Maybe that's why I was getting smell of diesel in the cab when I couldn't see a leak anywhere and couldn't find a hole in the exhaust.

While I am waiting for new washers and 0 rings, is there anything else worth doing while I am in there? I've cleaned out the egr and tested it's working, replaced a bit of hose that was collecting crap on its surface and I've already got newish filters in there. Course, it may never go again when I get the injectors back in, but I may as well hope for the best.

I don't; know that there is anything wrong with the high pressure pump. Before I took the injectors out I had a look on start up and there's nothing leaking out of it. There was a kind of swishing 'filling' noise as it primed, but I assume (and hope) I only heard that because I was so close to it.

Are there any tell-tell signs I should be looking for re. the high pressure fuel pump. apart from leakage?

Again, if anyone picks this up - tomorrow putting everything back together. I've read the system is set priming, so presumably air is automatically purged. Are there any known issues with this?

MGT said:

I've read the system is set priming, so presumably air is automatically purged. Are there any known issues with this?

Click to expand...

It's self priming, so just let the electric fuel pump do it's thing for a minute or so, then fire her up.

Nodge68 said:

It's self priming, so just let the electric fuel pump do it's thing for a minute or so, then fire her up.

Click to expand...

Thanks once again Nodge.

Should the injectors rotate fairly easily when put back in? I'm a bit suspicious given how tight they were to rotate when taking them out. Back in they all rotate freely . . They have new copper washers and 0 rings, and the nuts on the collars are are tightened down. just a bit concerned that there is a proper seal with the copper washer when the body of the injector is able to pivot so easily. Not being lazy - couldn't find a straight answer when googling for the answer.

Solved. In the unlikely event someone else is as daft as me, I will leave the above post. Warning: do not put the injector collars in upside down, because then you will get free movement. I imagine if you then start the motor you will get four lovely fountains of diesel all over the inside of the engine compartment.

MGT said:

Should the injectors rotate fairly easily when put back in? I'm a bit suspicious given how tight they were to rotate when taking them out. Back in they all rotate freely .

Click to expand...

No, they should be locked tight in position. If they rotate, then the copper washer isn't being compressed, so it won't seal.
Have you put the clamp forks on the correct way, so they're pressing down hard on the injector register?

Nodge68 said:

No, they should be locked tight in position. If they rotate, then the copper washer isn't being compressed, so it won't seal.
Have you put the clamp forks on the correct way, so they're pressing down hard on the injector register?

Click to expand...

I have now (see above). I put all four on the wrong way, so at least I was consistent. Fortunately I had a 'that can't be right, surely' moment.

Now they are well seated with no play at all.

Only niggle left (I hope) is not being able to find torque values for the nuts on the feed pipes from the common rail to the injectors. Mind you, I don't have a torque spanner, only a wrench, so I will have to go by feel. I'm concerned not to strip any threads.

MGT said:

Only niggle left (I hope) is not being able to find torque values for the nuts on the feed pipes from the common rail to the injectors. Mind you, I don't have a torque spanner, only a wrench, so I will have to go by feel. I'm concerned not to strip any threads.

Click to expand...

fuel pipe union nuts .. are 20nm / 15lb.ft ..
[ fuel injector nuts are at 10nm / 7lbs.ft ]
i.e. easy to overtighten .. more or less ..

hd3 said:

fuel pipe union nuts .. are 20nm / 15lb.ft ..
[ fuel injector nuts are at 10nm / 7lbs.ft ]
i.e. easy to overtighten .. more or less ..

Click to expand...

Thanks very much. I'll check those in the morning.

MGT said:

Are there any tell-tell signs I should be looking for re. the high pressure fuel pump. apart from leakage?

Click to expand...

they can leak inside .. whereas the leaked fuel ends up in the oil sump .. so note oil level

if the internal pistons wear excessively.. the pump can't supply what's demanded of it ..
especially at lower rpm .. and warm ambient temps ..
symptoms: .. may start fine when cold .. but needs excessive cranking when warm ..
and engine might go into limp-mode if the go-pedal is pressed too sharpish ..
and the fault code '' P1190 Governor / fuel plausibility deviation at high (engine) speed ''
would be logged ..

``````````

hd3 said:

they can leak inside .. whereas the leaked fuel ends up in the oil sump .. so note oil level

if the internal pistons wear excessively.. the pump can't supply what's demanded of it ..
especially at lower rpm .. and warm ambient temps ..
symptoms: .. may start fine when cold .. but needs excessive cranking when warm ..
and engine might go into limp-mode if the go-pedal is pressed too sharpish ..
and the fault code '' P1190 Governor / fuel plausibility deviation at high (engine) speed ''
would be logged ..

``````````

Click to expand...

That's very interesting, thanks. Also interesting is your thread on why injectors fail, which also has relevance to the breakdown of my oil boiler. I shall mine that for useful information.

All back together but won't start. Engine turns over but no firing. Taken return hoses off to make sure diesel reaching injectors, and it is reaching all four.
Made sure injectors seated properly as far as I can tell.

Aside from obvious - that I messed up the injectors when cleaning them - any ideas what it could be?

It is turning over but not even giving the smallest hint of catching.

Battery strength reads 12.56 after a few attempts at starting it.

It looks as if clogged injectors were not the issue, since this is more or less what I was experiencing before I took them out to clean them.

The sump does not seem to have more volume in it.

I've unscrewed the nuts on the feed pipes to the injectors to make sure no airlock and diesel getting through.

To see if diesel getting through from the common rail- injectors pipes I unscrewed the nuts and turned ignition to prime. Fuel came out but no indication it was under pressure. I do not know whether it should blast out or not or whether the high pressure only kicks in when engine turned over.

There is sometimes an odd grumbling noise when you turn the key coming from somewhere on the right of the engine bay as you see it from the driver's seat. I really couldn't describe it except to say it's almost like a low grumbling boiling noise. It goes with the swooshing or swishing noice which I took to be fuel in the pipes moving when ignition turned prior to engine starting. not always audible.

I realise I'm asking for a lot of advice here, and I appreciate it might get irksome, but if I could trouble y'all for just a little while longer - took the injectors I cleaned out to replace them with ones from donor vehicle (which should be ok) and found them in a lake of diesel as I pulled them out. Ie, the pump had been delivering fuel but it was just accumulating instead of igniting. Is that lack of sufficient compression from the high pressure pump?

Where was the diesel accumulated?