Injectors

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Sergeant
Jul 27, 2017
361
143
0
Ride
335i
Hi Everyone,
I've recently been seeing LTFT1 at 25% while LTFT2 is often around 5%.
I do need to replace the secondary lambda sensors but having had my car for 10 years now the injectors could well be due.
We didn't have any kind of recall in the UK that I'm aware of.

I can get index 12 injectors for £250. Right before covid I was going to get some injectors as preventative maintenance. Unfortunately I didn't.

I have seen non-index 12 injectors for almost half the price. So I wanted to ask. Have people had any luck long term with refurbished injectors?

One thing I'm very curious about is if the 6 digits on the side will be valid once an injector is refurbished?
Do they retest for flow etc and alter the 6 digits? I would guess not. Does that then make coding the injectors inaccurate.

I'm just wondering if I get the index 12s or go for the cheaper option. More interested in people's experiences than speculation. Thanks :)
 

IQraceworks

Corporal
Jul 7, 2020
217
136
0
Missouri
Ride
07' BMW 335i
If you were here in the US, I would tell you to send them to me so that I could hook them up and check them out, but shipping them here and back from the UK just isn't worth the money. I've been cleaning/flowtesting/high pressure leak testing N54 injectors for a while now....probably gone though close to 40 sets of injectors for people over the last several months. It's amazing how bad some of the injectors can get before people actually know they have issues.

As far as "Refurbishing" them goes.....there are a couple of big injector shops in the US that claim they can "Recharge" the internal piezo crystal stack in the injectors, but even then they will tell you there is no guarantee that it will fix them, or correct any issues that they have....and unless it's an index12 injector, they won't even touch them. I've had decent luck ultrasonic cleaning them, and backflowing them if necessary....but sometimes that still won't correct bad spray patterns or big leaks. I've had some that just flow like a garden hose as soon as you get the pressure to them.

If I were you, I would try to find a low mileage set of index12 injectors.....some that have at least been tested for leaks. That doesn't 100% mean that they are in good working order, but it's a pretty good sign they should be good. That's the main issues with these injectors.....leaks.

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RTA

Private
Jun 17, 2020
47
20
0
Not to be a smart guy, but I have pretty well sourced info that these injectors should not be cleaned by ultrasound, it will cause permanent damage, initially it will look good but the ultrasonic proces triggers a degradation proces of the injector internals, neither the piezo cristal can be regenerated.

This info I have is from two different sources, a Siemens engineer involved in their injector products and a supplier of ultrasound cleansing systems.

This after finding out that injectors these days cost crazy prices compared to the "good days" (75-100 euro a piece) and my research into alternatives, unfortunate you want to replace with new index 11 or 12 injectors (12 ideally). These injectors put a big value hit on these cars as replacing them costs a fortune and could make the car total-loss.

Would be nice if the US trade office or the EU market commission would dive into this :)

PS: if this is wrong Im very keen to hear the best alternative.
 
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IQraceworks

Corporal
Jul 7, 2020
217
136
0
Missouri
Ride
07' BMW 335i
Not to be a smart guy, but I have pretty well sourced info that these injectors should not be cleaned by ultrasound, it will cause permanent damage, initially it will look good but the ultrasonic proces triggers a degradation proces of the injector internals, neither the piezo cristal can be regenerated.

This info I have is from two different sources, a Siemens engineer involved in their injector products and a supplier of ultrasound cleansing systems.

This after finding out that injectors these days cost crazy prices compared to the "good days" (75-100 euro a piece) and my research into alternatives, unfortunate you want to replace with new index 11 or 12 injectors (12 ideally). These injectors put a big value hit on these cars as replacing them costs a fortune and could make the car total-loss.

Would be nice if the US trade office or the EU market commission would dive into this :)

PS: if this is wrong Im very keen to hear the best alternative.
You realize that all the high end GDI injector cleaning systems available on the market come with ultrasonic cleaning equipment as part of the system....right? What makes the N54 injectors different than all of the other types of GDI injectors out there? It's been a well established industry practice for years and years to ultrasonically clean fuel injectors, including GDI piezo type injectors. Just stating the facts.....

Until there is an industry wide announcement stating that ultrasonic cleaning will damage DGI injectors....I'm going to stick with the industry standard process.
 
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carabuser

Lieutenant
Oct 2, 2019
894
1
800
0
UK
Ride
Z4 35i & 335i
You realize that all the high end GDI injector cleaning systems available on the market come with ultrasonic cleaning equipment as part of the system....right? What makes the N54 injectors different than all of the other types of GDI injectors out there? It's been a well established industry practice for years and years to ultrasonically clean fuel injectors, including GDI piezo type injectors. Just stating the facts.....

Until there is an industry wide announcement stating that ultrasonic cleaning with damage DGI injectors....I'm going to stick with the industry standard process.
Do you have any before/after comparisons of the cleaning? Interested to see if you had an improvement in spray pattern after cleaning.

Also if they are leaking under 700psi, do they still leak after cleaning?
 

IQraceworks

Corporal
Jul 7, 2020
217
136
0
Missouri
Ride
07' BMW 335i
Do you have any before/after comparisons of the cleaning? Interested to see if you had an improvement in spray pattern after cleaning.

Also if they are leaking under 700psi, do they still leak after cleaning?

Yes, on every set of injectors I run, I do pre and post-cleaning CC volume tests, and put it on a report. If the injectors are in good shape, they usually don't gain a bunch of CC's after a cleaning, but I've had some pretty nasty ones that gained a bunch. As far as leaks go, it's kind of hit or miss. I run them up to 2,000psi to check them. Sometimes a cleaning (or multiple cleanings) will get them to stop leaking, but sometimes it won't. I've also had some that didn't leak, but had horrible spray patterns, and flowed way to much (or less) than they should compared to the rest in the set. So there are multiple things that can make them "bad". I also run themal imaging on the injectors, just to check for any hot spots of heat anomolies that might indicate some type of internal issue. No other injector shops I know of do that. Shoot me a PM and I can get you more info. Thanks!