Did you have 3 fall apart when you pulled them out our you found 3 were bad.
The biggest issues with the different injectors is how they will flow in relationship to the other injectors you have. That will be a big issue.
They came out just fine. 2 of them were still flowing at a lower rate after the cleaning and one of them had a slight problem with the electrical connector, so better safe than sorry.
I’m only asking because I found a set of 4 Hitachis in stock online - but they seem to be priced like the RS4 injectors @ $50 ea, even though they were listed for the 5.2L, which are normally $120 ea. Maybe it’s too good to be true…
The Hitachis work fine. If you want to be extra sure, take them to a local injector testing shop and have them flow tested.
I read somewhere that the hitichis had a few injectors that had the same part number but appeared to flow differently. Have you herd of this. From the post you made it sounds like you might.
Kind of different because it is an V8 S5 but I wanted to share something that happened recently because this can help with diagnosis.
A guy that I know with a V8 S5 had a flashing check engine light and misfires. I looked at it to find that cylinder 8 had a dead cylinder with constant misfires. Just to double check things I looked at the fuel pressure mvbs (103, 106, and 140) to find that the engine had low fuel pressure before starting the engine, once the engine started the low side and high side rail pressures got up to what they should be after a second with the rail pressure just slightly hovering below specified at times, and then once I shut off the engine the fuel pressure would bleed down to like 1 bar. Pulled the cylinder 8 spark plug to find it was flooded with gas.
Took all eight injectors out and had them mailed off to be cleaned, rebuilt, and flow matched. Apparently the injectors for cylinder 1 and 6 were dripping at first with only like 70 some PSI put to them. The cylinder 8 injector just had a steady stream of fluid going through it. The shop tried cleaning that cylinder 8 injector multiple times both forwards and backwards with no luck so they recommended replacing it. I had already ordered a new injector just in case but I was curious to see if it could be saved.
All of this was on a 2010 V8 S5 with 70Kish miles that has never been carbon cleaned. Just figured that I should post this info to give some insight that it isn’t always possible to save an injector by sending it out to be serviced.
Great post jimmy. I think we really need information like that. These injectors are just getting to the age where we are just starting to see failures and I dont think enough people know about them and the issues that they have
What’s your gentlemen take on injector cleaning on B6/7 S4s?
No real need. You can do it but the FSI injectors really get messed up and get carbon in them. That causes all kinds of issues. Generally you dont see the same issues with the SI injectors. It cant hurt to have them cleaned if your over 100k but usually we dont see the same kinds of issues or changes the FSI guys see with a cleaning.
Some great info here
After a little help if possible
My B7 RS4 is on 113k miles and I have just completed a carbon clean, new gaskets, intake manifold clean etc
Before this I am experiencing a lot of hesitation and jerking under light throttle and the car seems to bog sometimes under WOT, but other times pulls hard.
After reading this I have taken some logs with VCDS and I will post the log later when on the laptop but for now I have noticed the following
My long term fuel trim at idle on both banks is slightly negative, around -1.5 and long term fuel trim at load was around +7.4% on bank 1 and +6.6% on bank 2
I then completed a few 3rd gear pullS from 3k to 8k
After this my long term fuel trims at load on both banks have gone up to +9.9%
whilst doing this I was monitoring MAF readings and only reached a maximum of 135 g/s
Car is stage 1 tuned with the following modifications
BMC air filter
Forge oil cooler
Aux rad removed and cold air feed fitted
Carbon cleaned less than 500 miles ago
Pre cats removed
Miltek res cat back exhaust
As far as I am aware injectors are originals, so thinking of changing them first, would I be correct in thinking the low MAF reading is a result of the engine not getting enough fuel and therefore not achieving full power or could the MAF be the cause of the fuelling problem?
Any help would be 
Honestly. So many people have hurt motors on these cars. And if you follow the injectors that are available in the RS4 and all of the other cars they come in. You find one common thread. These injectors either need to be serviced… And when I say serviced. You have to do it right. A lot of the injector places just do low pressure cleaning and that ends up being only kinda helpful.
Getting new injectors is always a good way to go but those are not generally flow matched like the serviced ones. But I would 100% tell you to either replace or service the injectors. Even if you wre not having these issues. Anything over 85k… It is injector clean or replace time on most of these cars
PS welcome to the forum.