Bongo Fury

I was originally only removing them to take to a specialist for cleaning, but one unscrewed whilst I was removing the 18 mm nut that holds the banjo union for the return fuel. As it came apart so easily, I thought I would give it a go, and am glad I did. This resolved a slowly worsening lumpy cold start issue I had been putting up with. I have regularly used injector cleaner, but there was a good dose of carbon on the needle and injector head. It isn’t a hard job so long as you note how it came apart (hence the photos) and keep everything scrupulously clean.

Remove the injectors.

Give them a good clean externally with fuel and a lint free cloth in order to get the worst off.



Injector before.





Using Spanner and socket to unscrew injector body

Using a spanner (18 mm I think) and the same socket used to remove the injector (21 mm double depth), carefully loosen the injector body from the union housing. Unscrew them over a white sheet/piece of paper and noting the order and orientation of assembly remove the:

Shim
Spring
Top-hat
Slotted Disc
Needle
Injector Head



Complete assembly reduced to components

Again, using fuel and a lint free cloth, make sure everything is perfectly clean. I used a pin, a scalpel, a parts washer, a plastic scourer and an airline to remove any carbon from the needle tip and injector head. Be careful not to score or scuff any parts, particularly the sides of the needle as this is a moving part. Give the whole lot a wash out and blast with an air line before reassembly.

Note: Do them one at a time as you don’t want to muddle any parts. The shim is matched to the injector assembly. The injectors work on fine tolerances, so keep everything clean.

Put everything back together in the correct order and do up again with the spanner/socket combination. Don’t strip the threads! I didn’t use a torque wrench, I just tightened to about two white knuckles!

Refit, crank until engine starts and then be pleased you have saved yourself £15 per injector.

Good to know they're relatively easy to do, good work. Word of caution, these work at very high pressure, get it wrong & you'll wipe out that saving & then some in no time. Only tackle this if you're really sure what you're doing.

missfixit70 wrote:Good to know they're relatively easy to do, good work. Word of caution, these work at very high pressure, get it wrong & you'll wipe out that saving & then some in no time. Only tackle this if you're really sure what you're doing.

Toally agree with that. I just cannot help my curiosity!

I used to do these onboard tankers (slight size difference ) We used to have ultrasonic cleaning kit, heavy duty chemicals & proper pressure testing cabinets, half the time you'd have to redo them if the spray pattern isn't quite right, doesn't lift at the right pressure etc.
I must admit, I think I'd probably pay the money on this one, or at least find someone with testing gear, if you're having issues, you still don't know if they're working right or it's something else.

BongoMTBer wrote:I was originally only removing them to take to a specialist for cleaning, but one unscrewed whilst I was removing the 18 mm nut that holds the banjo union for the return fuel. As it came apart so easily, I thought I would give it a go, and am glad I did. This resolved a slowly worsening lumpy cold start issue I had been putting up with. I have regularly used injector cleaner, but there was a good dose of carbon on the needle and injector head. It isn’t a hard job so long as you note how it came apart (hence the photos) and keep everything scrupulously clean.

Remove the injectors.

Give them a good clean externally with fuel and a lint free cloth in order to get the worst off.



Injector before.





Using Spanner and socket to unscrew injector body

Using a spanner (18 mm I think) and the same socket used to remove the injector (21 mm double depth), carefully loosen the injector body from the union housing. Unscrew them over a white sheet/piece of paper and noting the order and orientation of assembly remove the:

Shim
Spring
Top-hat
Slotted Disc
Needle
Injector Head



Complete assembly reduced to components

Again, using fuel and a lint free cloth, make sure everything is perfectly clean. I used a pin, a scalpel, a parts washer, a plastic scourer and an airline to remove any carbon from the needle tip and injector head. Be careful not to score or scuff any parts, particularly the sides of the needle as this is a moving part. Give the whole lot a wash out and blast with an air line before reassembly.

Note: Do them one at a time as you don’t want to muddle any parts. The shim is matched to the injector assembly. The injectors work on fine tolerances, so keep everything clean.

Put everything back together in the correct order and do up again with the spanner/socket combination. Don’t strip the threads! I didn’t use a torque wrench, I just tightened to about two white knuckles!

Refit, crank until engine starts and then be pleased you have saved yourself £15 per injector.

Brave man! And brilliant write-up/pics!

missfixit70 wrote:I used to do these onboard tankers (slight size difference ) We used to have ultrasonic cleaning kit, heavy duty chemicals & proper pressure testing cabinets, half the time you'd have to redo them if the spray pattern isn't quite wrong, doesn't lift at the right pressure etc.
I must admit, I think I'd probably pay the money on this one, or at least find someone with testing gear, if you're having issues, you still don't know if they're working right or it's something else.

As a get out of jail card, strip and clean has worked here........................But have to agree with Kirsty. Injectors need servicing as parts wear. Spray pattern needs testing and pressure setting. Great info though.

Yep, pleased it worked out ok for me.

I reckon 1.5 hrs of enjoyable fettling is worth saving a few £££. Must admit, I expected it to have not made a jot of difference when I put it together, but fixing the lumpy stat has demonstrated a satisfactory result. With hindsight, I cannot see what could really have gone wrong, apart from it not fixing anything and me having to remove the injectors again and taking them to a grown-up!

My original problem was still there, but I am now confident the injectors are not the problem. They are not complicated and the symptoms remain the same even with the improved cold starting. Also, I have just had info from one member of this forum who had the same symptoms and for him it turned out to be the pump or ECU. Since mine isn't a drive-by-wire system, my money is now on the pump.

The issue with high pressure is you get some diesel injected into your skin whilst dismantling, that would not be good! How does the amateur/DIY mechanic ensure there is no pressure at the injectors before dismantling?

miker wrote:How does the amateur/DIY mechanic ensure there is no pressure at the injectors before dismantling?

By making sure they are not attached to a running engine.

Fair one!

Damn damn double damned!!

I can't get the injector apart (have only tried one so far but have really pushed it and it isn't budging!)

They were rebuilt in October by a specialist but they appear gunked up again. 3 injectors were black and one was wonderfully clean.



Will try the others

All done, one injector was a swine but a bit of brute force (me and step-son) and ingenuity (my wife) we managed to get it apart.

All straight forwards.

Some observations...

The shim doesn't always come out

The copper washer at the bottom of the injector may need persuading off with pliers

The injector head may need tapping out of the bottom of the injector body

Cotton buds and carb cleaner work wonders (although I am now high as a kite!)

Whilst removing injectors it is worth removing the inlet manifold and cleaning it with degreaser and hot soapy water, mine was full of gunge so I am making up some EGR blanking plates. Part of my EGR was cracked and leaking!



Russ

Remember to either anneal the old copper washers or fit new ones