Failing injectors

[Kimovitzh]

So over the two + years that I have had my car, the injectors has been an occasional annoyance to me.
The first injector that started acting up was just changed without me thing about it.
But when I had more misfires two weeks later I pulled them all and back flushed them and to great success.
Then a year later, a couple of more started acting up. Replaced one and flusshed the rest.
But again this summer, cylinder 7 started acting up on our way to Switzerland, and on our way home cylinder 3 and 10 joined the party - 7 was good again, well sort of.
So, new injectors again.

I have 4 new injectors, and 6 old and original.
The new ons have filters, the old ones doesn’t.

So today I tidied up my workshop and when I was done I took the 4 old injectors that I had replaced and looked at them, thinking “why?” -it’s such a simpel design.

Then I looked at the inlet side where there’s a brass ring and some plastic. Where the new ones have filters.
I then took out that brass ring and saw how the plastic just crumbled with no effort.

You can even see how crusty and cracked the plastic are.

Last year when I back flushed the injectors a noticed some small hard black beads, but thought that maybe they were walnut shells, but looking at what I found today I now realize that it’s the injectors them selv that supply their own failure.

So, next weekend I’ll pull the six old injectors and remove this thing and see how long I’ll be able to go before my next misfire/injector error occurs.

Do you guys think that this could be the remaining of a filter that have been dissolved over the 15 years that this engine has been running?

[Kimovitzh]

Looks like they could have been that type?

[laketahoequattro]

Damn I have not seen that yet. Nice quality! That is why I went with 10 new ones to be safe for a nice $83 a piece on sale.

Sorry to hear about your issues but good find

[Kimovitzh]

Good price!
If I’m lucky I can get them to 140$ per piece, otherwise they are 240$.
Can’t imagine what they would cost over at Audi

[Kimovitzh]

So on the 26 of July I flushed all the injectors.
14 days later with driving this is what was inside the six injectors with the failing filters.

Debris of plastic.

So I removed the brass fittings.
Pay attention to the plastic rods.
There’s two on each filter. And well … there’s six brass rings so there should have been 12, only five rods were left.

I hope to see no more misfires due to this failing filter!

[eng92]

I had my share of injector woes during my first year of ownership.

I took them to a place that does DI injector cleaning and they found the filters in the condition shown in the picture below. The owner of the company said that this is something he sees in vehicles that people have run a lot of oncar injector cleaners through.

The car ran great for several months and then I had a single injector stick open.

Below is a picture of my injector collection in late 2018 when I was doing an engine re-build.

Check the date codes on your injectors. My car is an 07 and I purchased it in 15. One injector was likely replaced in 08/09. Another six were done in 14/15 (probably the original owner trying to get the engine to run properly before trading it in to the place I purchased it from). I replaced the one that stuck open in 2016. I replaced the remaining three original ones in 2018 when I had the engine apart.

[Kimovitzh]

All my problems seems to be related to the debris. If new injectors wasn’t so expensive I would have replaced them all.
But hunting down stuff like this is also fun and rewarding.

I would guess that cleaners do stuff like this and it would be a loop.
Misfires -> injector cleaner -> trashed filters -> misfires -> repeat.

I think that the injectors that I haven’t replaced is the original ones. So four new Hitachi and six original. I’ll see what date the four I have replaced has on them tomorrow.

And thanks for the picture, it really shows what has gone through my injectors since

[laketahoequattro]

I still have my original 10 if there is ever a good rebuild solution

[eng92]

I guess it depends on your definition of rebuild. Mine is completely disassembling something down to its individual components, cleaning and checking everything against factory spec, replacing all wear parts and then reassembling. You will never see that offered for our injectors as it would not be cost effective.

If you Google rebuild kit for our injectors, all that comes up is the replaceable external parts (ie filter, teflon ring, o-ring, etc.

If I had to do it all over again. I would have replaced all of my injectors as soon as the injector cleaning service informed me that the filters had disintegrated inside of them.

Ultrasonic cleaning is ideal for removing the fuel deposits and carbon from the injector. However, it does not necessarily break down all of the pieces of broken up filter materials that may have found their way deep inside the injector.

I found this out the hard way after after having an injector stick open about 5K after getting them cleaned. I was completely misfire free up until that point.

Below is a picture of an old injector I just cut apart to give people an idea of what is inside them.

[Kimovitzh]

Just serviced my dads C6 A6 3.2 V6.
Same case with the injector filters.
Mesh was gone and left was the fragile plastic causing misfires.