Fuel Injectors questions

[mrgreen387]

I've see some people take their fuel injectors to injectors cleaning services. But why not just buy new one from the shop? Would it make any difference? Is stock fuel injectors better than from Bosch or what? https://www.ecstuning.com/b-assemble...3647830975kt2/

Please let me know. I plan to replace with fuel filter too.

[terra]

Once upon a time the Bosch injectors were a lot more expensive. Now it makes sense to just buy new vs getting them cleaned IMO.

[ATB88]

How timely: I just ordered a fresh set of Bosch injectors from FCP. I strongly recommend that you do, too While some fuel injection places might do a great job at cleaning/flow testing old injectors, if your car experiences any fueling related issues down the road it'll be hard to be 100% sure that your injectors aren't the problem. New injectors cost only $130 than having your injectors cleaned and I think that's well worth the cost for such a critical component

My personal anecdote on how injector cleaning went wrong for me: just an hour ago I finally discovered that a longterm fuel trim issue that I had been chasing for over a year and a half now was being caused by my fuel injectors that had been "cleaned". I had ruled them out as being the cause of the problem because a year ago they were only 50k miles old *AND* I got them cleaned and flow tested at a reputable fuel injector specialist in socal (RC Fuel Injection). They gave me graphs and data showing their worse flow characteristics before and how perfect and balanced they all were after. Sure enough, after putting them back into the car, my issue persisted so I said okay, well the injectors are good, so it's something else. Turns out that was wrong. Today I got creative and spent some time swapping injectors between bank 1 and bank 2 and found that you could create large differences between the bank 1 and bank 2 fuel trims depending on which injectors were where -- obviously the injectors were not balanced and achieving the same 259cc/min flow rate across all 6 injectors that the graphs and datasheets they gave me said they did. Really makes me question whether or not the "after cleaning" data they gave me for the injectors was completely fabricated? Their "expertise" had me so convinced that my issue wasn't my injectors that I've spent a lot of time over the last year diagnosing and refreshing parts needlessly. I'll make a thread about this once I get new injectors installed and confirm, but I'm pretty sure I'm right.

[mrgizmo04]

How timely: just an hour ago I finally discovered that a longterm fuel trim issue that I had been chasing for over a year and a half now was being caused by my fuel injectors. I had ruled them out as being the cause of the problem because a year ago they were only 50k miles old *AND* I got them cleaned and flow tested at a reputable fuel injector specialist in socal (RC Fuel Injection). They gave me graphs and data showing their worse flow characteristics before and how perfect and balanced they all were after. Sure enough, after putting them back into the car, my issue persisted so I said okay, well the injectors are good, so it's something else. Turns out that was wrong. Today I got creative and spent some time swapping injectors between bank 1 and bank 2 and found that you could create large differences between the bank 1 and bank 2 fuel trims depending on which injectors were where -- obviously the injectors were not balanced and achieving the same 259cc/min flow rate across all 6 injectors that the graphs and datasheets they gave me said they did. Really makes me question whether or not the "after cleaning" data they gave me for the injectors was completely fabricated? Their "expertise" had me so convinced that my issue wasn't my injectors that I've spent a lot of time over the last year diagnosing and refreshing parts needlessly. I'll make a thread about this once I get new injectors installed and confirm, but I'm pretty sure I'm right.

In any case, I just ordered a fresh set of Bosch injectors from FCP. I strongly recommend that you do, too

Did you also reset adaptations after swapping?

[ATB88]

Did you also reset adaptations after swapping?

Yeah, so, eventually yes, here's what I did: with the injectors in their "default" positions (these positions were the same before and after I took them out and brought them to RC for cleaning), what I was seeing was high LTFTs in both banks (ranging from 7-12 depending on conditions), but, one thing that was always consistent was that bank 1's LTFT was *always* a consistent 60%-70% higher than bank 2's. So, say, if bank 2 was at 7.8%, then bank 1 was at 12%.

My hypothesis was if the reason for the large difference in bank 1 and bank 2 was due to the injectors, then, if I swap bank 1s injectors to bank 2 and vice versa, and then go for a drive, I would expect to see bank 2's LTFT go up, bank 1's LTFT go down, they would meet at some point, and then eventually bank 2 would become the consistently higher of the two. So I swapped injector 1 <-> injector 4, 2 <->5, 3 <-> 6, and went for a nice looong drive. First of all, the car felt the best it's felt since I've owned it, and like it had "woken up", it was crazy. Second, I saw exactly the behavior in the LTFTs that I hypothesized: bank 1 went down, bank 2 went up, they met in the middle, then continued on their trajectories. By the end of the drive, they were stable at 7% for bank 1, 9.4% for bank 2, and had been sitting at those values for 20 minutes.

Then I hooked up INPA, reset adaptations and went for another drive. LTFTs again settled to the same thing: 7% for bank 1, 9.4% for bank 2.

So, the disparity between the fuel trims seems indeed to be due to differences between the injectors themselves.

It still remains true that my LTFTs are, in general, quite high, and that may be a separate issue. But it wouldn't shock me if there were just baseline problems with all of the injectors (causing high fuel trims in general) and some are just worse than others, which is what caused the consistent disparity between the two banks. But that's conjecture at this point, we'll see about that when I put the fresh injectors in. Either way, it definitely seems pretty clear that at least one aspect of my issue comes down to my injectors. The fact that the car automatically drove so much better after the swap is pretty surprising, though.

[Albertan]

Just a note. the link to ECS for new injectors are NOT Bosch injectors. I had an issue with my daughters e46 330ci. stock injectors were leaking in cold weather. I bought new from Rock auto. With in a mile I got check engine light. I fooled around and eventually figured something wrong so they sent another set. Same thing. Then I realized that they were Chinese. I bought a final set from a wreck and now the car is fine. So buying new injectors, make sure they are name brand. I learned my lesson.

[see.m3.go]

Just a note. the link to ECS for new injectors are NOT Bosch injectors. I had an issue with my daughters e46 330ci. stock injectors were leaking in cold weather. I bought new from Rock auto. With in a mile I got check engine light. I fooled around and eventually figured something wrong so they sent another set. Same thing. Then I realized that they were Chinese. I bought a final set from a wreck and now the car is fine. So buying new injectors, make sure they are name brand. I learned my lesson.

It says on the bottom of the page OP linked that they are Bosch injectors. Is there something I am missing? Are there two versions of the Bosch?

[ATB88]

Just a note. the link to ECS for new injectors are NOT Bosch injectors. I had an issue with my daughters e46 330ci. stock injectors were leaking in cold weather. I bought new from Rock auto. With in a mile I got check engine light. I fooled around and eventually figured something wrong so they sent another set. Same thing. Then I realized that they were Chinese. I bought a final set from a wreck and now the car is fine. So buying new injectors, make sure they are name brand. I learned my lesson.

To be fair, of the five injector options listed on rockauto for the 330CI, none of them say directly that they're Bosch or OE, which ones did you buy? ECS says theirs are Bosch, I'd be pretty shocked if they were knockoffs. How did you determine the ones you got were Chinese?

That said, I would (and did) go FCP Bosch for warranty. We'll see how they do tomorrow!

[Albertan]

It was very cold and I didn't want to go salvaging injectors. I figured they were cheap at Rock Auto. They were not listed as a name brand. I thought they would sort of work at least for a while. I was wrong. Look back at the ECS link. It says brand: ASSEMBLED by ECS Tuning. I don't know what the Bosch name is down below for unless it is for the clips. In any event, I would clarify with ECS before ordering. They might be very good parts. "Trust but verify" where have I heard that before?

[ATB88]

It was very cold and I didn't want to go salvaging injectors. I figured they were cheap at Rock Auto. They were not listed as a name brand. I thought they would sort of work at least for a while. I was wrong. Look back at the ECS link. It says brand: ASSEMBLED by ECS Tuning. I don't know what the Bosch name is down below for unless it is for the clips. In any event, I would clarify with ECS before ordering. They might be very good parts. "Trust but verify" where have I heard that before?

Yeah I've never actually checked out rock auto out before, but wow, my god those parts are cheap. Makes sense that they're not OEM, though.

"Assembled by ECS Tuning" means that it's a kit whose contents come from varying different brands, but the specific brands of each item in this kit are listed lower in the page. In this case it confirms directly there that the clips are BMW brand and that the injectors themselves are genuine Bosch, as seen below. Definitely good to be double checking what brand of parts you're ordering in kits like this, though!

[terra]

So for whatever it's worth, the clips are wrong (BMW themselves have it mislisted). These are the correct ones: 13531274729

[Epsilon]

Are new clips necessary?

[terra]

Are new clips necessary?

Shouldn't be. I'd probably buy a couple just in case I drop / lose one. At a buck a piece it's not too bad.