Fuel Injector Cleaning

When running high boost situations you want your injectors to be flowing at their best. If you buy a set of used injectors especially DSM 450cc injectors its recommended you get them professionally cleaned. I have had two sets of fuel injectors cleaned. I really like the guys over at Deatschwerks These guys really know their stuff. They also go the extra mile in their service, they replace the filter in each injector as well as include new O-rings. Their basic service starts at $19 per injector. They also sell new 3000gt Vr4 injectors so be sure to check them out. Members of this site will receive a discount so join for free and read the details on how.


Here is the write up for my last fuel injector cleaning. I am installing my new 19T turbos and will get car re-tuned so i wanted to have the injectors running at their best and importantly spraying an even pattern of fuel.


When starting a service, the notes section of the service order form is checked first. A lot of the times, a customer will have a specific problem; so we do a physical check of the injectors. We look for blemishes such as dented nozzles, torn orings, or other damage that could be causing an issue.

Some of the Orings were torn, but most likely that was from removal. All the injectors are in excellent physical shape.

Second, I engrave each injector with a unique number so the customer can identify them on the report. The Injectors were individually bagged with numbers, so I corresponded my numbering with the customer.

At this point, we coil test the injectors. We check the voltage draw and ohms of each injector, looking for inconsistencies. A bad coil is a common problem especially among older injectors. Once a coil goes bad, the injector must be replaced. A bad coil automatically stops the service and we contact the customer to discuss his possible options. If we cannot replace an injector, or the customer wants to find a replacement on his own, we can either service the good injectors or send them back at no charge.

All the injectors tested within spec, so its time to move on to the pre-flow. For the Dynamic service, we do a pre-flow. The pre-flow test shows the state of the injectors as they arrived.  We test static and dynamic flow rates and also look for bad spray patterns and any sign of leaking. If the customer is concerned that one or more injectors is having a specific problem, this helps identify them.

None of theses injectors leaked, and all spray patterns were acceptable. The flow rates were consistent. Next we breakdown the injectors for cleaning. Top feed injectors have a small brass or plastic screen that acts as a small filter. They get checked for blockage when they are removed.

All o-rings and spacers are removed, and the injectors get a quick scrub in mineral spirits cleaning off any excess dirt. The ultra-sonication bath is the most important part of the cleaning process. The injectors are submerged in an ultrasonic cleaning detergent specifically for automotive parts. This bath breaks down dirt on the outside as well as the inside of the injector.  After twenty minutes, the injectors are removed from the ultrasonic cleaner and flushed. We flush the injector from the nozzle back out with solvent, making sure that all contaminants and excess detergent is removed from the injector.

At this point the Injectors are scrubbed in the parts washer one more time. New screens, and upper o-rings are put on, and the injectors are ready for the post-flow testing. During the final testing, we’re looking for any abnormalities in the spray patterns, flow rates, etc. We want to make sure they are 100% ready to be reinstalled before they are shipped back to the customer.

The results are checked over, and if any issues arise the customer is contacted right away.

As you can see in the results below, the injectors are have a much better balance, and the flow rates have increased. They are now ready to prep for shipping.

The ultra-sonication process can discolor and take paint off metal body injectors, so we wire wheel and spray with a high temp clear to protect them and make them look nice. Finally, the injectors are built for the application, pulsed with a oil blend to help keep the inside of the injector lubed, and packed. Also we include an o-ring lube for re-installing.

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