The market for Denso replacement injectors has changed dramatically in the past few years. While vast numbers of aftermarket options have become available (Blogs on the quality of these to come), so too have counterfeit injectors—many of which are now nearly impossible to visibly distinguish from the real deal.
At Diesel Geeks, we’ve always been cautious with sourcing, but even we’ve been shocked at just detailed these counterfeits have become. In the past, it was fairly easy to spot a fake injector. Poor packaging, incorrect markings, or sloppy machining were all dead giveaways. But today, some of these counterfeits are externally so on-point that even experienced diesel specialists struggle to tell them apart.
The Growing Problem of Counterfeit Injectors
Just yesterday, we received a set of injectors that simply would not code. At first, we assumed a minor issue, but after some digging, we discovered the injectors were counterfeit. What made this even more concerning? They were purchased from a well-known and reputable supplier here in Australia—who had no idea they were fake.
This highlights a major issue in the industry. More and more suppliers are unknowingly selling non-genuine injectors, believing them to be real. The packaging, markings, and even serial numbers often match what you’d expect from Denso, but these units simply do not perform to the correct specifications.
How to Identify a Fake Denso Injector
While counterfeits are becoming harder to spot, there are still a few telltale signs:
Coding Issues: One of the biggest red flags. If an injector won’t accept coding, there’s a high chance it’s not genuine.
Slight Variations in Finish: Small machining inconsistencies, fonts on the injectors or codes, the missing of the stars or circles on the end of the code, the wrong cap nut finish - Serial numbers are another good one - 0-12 are the first 2 digits, the letter is a year of manufacture based on a part number. These ones yesterday were 32X00353 (there's no 32 nor X)
Unusual Packaging: While counterfeiters are improving, incorrect labeling, missing holograms, or unusual fonts (in the case of the blue boxes - the word injector is the wrong font and THE ONLY GIVE-AWAY!) can still be giveaways.
Price That’s Too Good to Be True: If the price is significantly lower than what genuine units sell for, be cautious.
We’ve included four photos of injectors that appeared legitimate at first glance but turned out to be counterfeit. These images highlight just how convincing these fakes have become.
The Risks of Running Counterfeit Injectors
The biggest concern with counterfeit injectors isn’t just that they don’t perform anywhere near as well as the genuine product. We recently tested 36 injectors over 3 different part numbers (1KD, 4JJ1, 4D56 - 3 sets each) and all failed.
Issues include:
- Increased wear on the rest of the fuel system
- Poor fuel economy and performance issues
- Premature injector failure
- Engine smoothness, missing at idle, lack of performance
What Diesel Geeks Is Doing for the Injectors We Supply
At Diesel Geeks, we take this issue seriously. We try and source every injector from Authorized Denso Distributors, and when we cannot, it goes through strict verification processes to ensure it is 100% genuine. If we can’t verify the authenticity of a product, we simply won’t sell it - we don't want to supply inferior products, and frankly, we don't want the warranty risk
We also encourage workshops and diesel owners to be extra vigilant. If you suspect you’ve been sold a counterfeit injector, get in touch with us. We’re more than happy to help verify your injectors and guide you on what to look for.
Final Thoughts
The rise of counterfeit Denso injectors is a real problem in the industry. Even reputable suppliers are being caught out, and it’s becoming harder than ever to spot the fakes. If you’re buying injectors, be cautious. Stick to trusted suppliers, verify your products, and if something doesn’t seem right—question it.
At Diesel Geeks, we’re committed to ensuring you get the real deal every time. If you have concerns or need help verifying an injector, give us a call. We’re here to help keep your diesel running right.
The word injector, and the "c" in the serial number was the only tell. Otherwise, we don't know how else you'd know this was not legit
In the above case, the word injector was again the tell, and the fact that this part number has had a 'dull gray matte' finish on the cap nut for the past few years. If you were not familiar with these, you'd easily think this was genuine.
These were harder to distinguish. There was no indication at all in the above image.
Notice the code is missing the shape that is at the end of these injectors on genuine injectors. it's a SUPER minor point and not easy to spot.
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Tim
I have a late 2011 Hiace commuter 1KD 5 speed manual, ex hot swap disability taxi with 526,000km on the original injectors and motor, the pickup and inlets were cleaned at 300,000(which is a whole other story when I pulled the sump to check) and the lines and rocker cover were replaced by the original owner at 510,000. Just done 5,000km touring with the best economy 9.3l/100, worst 9.8l/100. Ran the aircon the whole time and didn’t overly baby it. Love the 1kd, love your site and will probably go down the new injector path soon as it is rattly cold, cheers.
dieselgeeks.com.au
Thanks so much for the kind words. I agree these engines are very good. They just need to be serviced well and on time and they just go and go and go.
Please don’t ever hesitate to reach out with any questions. We’re here to help!
Matty B