Fuel injectors... Counterfeit? Fine? How to diagnose?

[leapdragon]

So hearing stories about failed injectors leading to engine failure, I replaced the injectors on my 240k mile '07 pre-emptively with a new set of Bosch injectors from FCP. They seemed to run a little rough at idle, but would smooth out >1k RPM.

But my understanding was that the ECU in a gasoline (i.e. non-diesel) engine would gradually learn over time and even them out. Well... Drove for a month and that didn't happen.

I couldn't be sure that the vibration was due to the new injectors, just had that sense, so today I swapped the original set back in. Much smoother at idle, and even feels smoother when driving. Note that no codes were ever set with the new set in, and the fuel trims were <1.0 (i.e. no vacuum leak at manifold or anything like that).

The new injector set looks identical the old set (apart from being much cleaner) and the markings are the same. Any experts here who can answer the following?

- Does the ECU on gasoline engines really auto-adapt to these?
- Do I need to trigger an adaptation manually?
- Do I need to enter injector code (thought this was for diesel only, and I don't see any differing markings on them...)
- Does this likely mean that 1+ injector(s) are either defective or not well flow-matched?
- Is there some easy (and inexpensive) way to test them?

I hate to just discard them since I paid good money for them, and of course now 240k injectors are back in, which is what I was trying to pre-empt in the first place, but I hate to install them given that rough running means that obviously something isn't ideal with combustion. I doubt I can send them back after driving on them for a month and I really don't want to try to figure out if Bosch has some sort of RMA procedure as that sounds like it'll take more time and aggravation than their cash value

Thoughts?

[abscate]

It’s possible the new ones didn’t seat right or an oring turned.

I would write FCP a note saying defective product and ask for return on warranty.

[Vova585]

All injector testing is associated with fire risk.
Best to test injectors outside of the car in the well ventilated area.
Assuming we dont have dedicated equipment, one can go to junk yard and remove fuel rail from similar style injector car. You will need fuel pump and battery as well. Get yourslef electrical connector while at junk yard as well.
Connect the fuel pump to the rail with oil resistant fuel injector grade hose. Can improvise fuel tank from 1 gallon container(old oil jug). Place battery several feet away from your tank and connect/disconect power supply through alligator clamps or similar. Get yourslef 200cc or bigger graduated cylinder and attach power supply to the injector. First test is to see pattern of spray. It should be cone shaped and not dripping/stream etc. Next test is to compare how many mls injector pumps during period of time and compare those values to the rest. (Usually 20sec time period)
But if your old ones are working great-just change file filter and periodically add your favorite injector cleaner(royal purple, ....).

[vtl]

Symptoms tell you had a vacuum leak. Or injectors were underdelivering fuel. But in latter case ECU would be able to adapt to it by adjusting fuel trim.

[jonesg]

there are bootleg injectors , complete with bar coded boxes you'd have difficulty catching, mostly sold on ebay.
You might want to ohm test the new ones.
Pity you dodn't do a misfire count test when they were installed.

[Vova585]

I can possibly see only 1 scenario where Jonesg's suggestion can be correct. Someone bought a set of cheap counterfeit injectos from ebay, amazon, alibaba..and then bought a set from fcp. Later counterfeit was placed into original boxes and sent back to fcp as "newer installed".
LeapDragon did everything he could to insure he bought quality part-bought from fcp. There were no reports of misfire in his original post as well. Given such, suggestions by abscate and vtl are better.

[vtl]

I can possibly see only 1 scenario where Jonesg's suggestion can be correct. Someone bought a set of cheap counterfeit injectos from ebay, amazon, alibaba..and then bought a set from fcp. Later counterfeit was placed into original boxes and sent back to fcp as "newer installed".
LeapDragon did everything he could to insure he bought quality part-bought from fcp. There were no reports of misfire in his original post as well. Given such, suggestions by abscate and vtl are better.

I once was bought CRP exhaust valves from FCP. What I've got was reground old cracked dinged valves sprayed with paint. Don't know if it's what CRP itself does or if it was counterfeit product, but FCP still sells them. Perhaps was counterfeit.

[DavidE7]

Send the old set of injectors to these guys for cleaning, rebuild, and balance testing:
https://www.hurstinjectorservice.com/index.html

Then put the originals back into the car.

[vtl]

I had mine rebuilt at home (new filter, O-rings, caps) and cleaned for consistent spray pattern. May need to redo it, this was 8 long years ago. Or, maybe, not. Fuel trims are nearly ideal.

[jonesg]

counterfeit parts plague the commercial aviation industry where a single screw can cost $30, plenty of money to be made there.
And aviation is heavily regulated.
Its also become a problem in healthcare , even the military deals with it.

how to spot fake bosch injectors.