3 Ways To Clear Out Your SR20DET Injectors After A Long Off Season

8 April 2015
 Categories: , Articles


If you have not driven your car in a long time, starting it back up may reveal a host of problems. Even after getting the engine to stay running, you may notice noisy injectors or intermittent misfires. Both of those problems point toward clogged SR20DET injector nozzles as the cause. Although you could drive your vehicle with those problems, you may notice a loss of power at high RPMs or excessive detonation in the cylinder. If any of the injectors clog all the way shut, engine damage could occur. Luckily, there are several ways to clean out your injectors to restore their spray pattern and quiet operation.

High RPM Runs

Sometimes just driving the car at its limits can clear out debris in the fuel system. You will want to run through the gears, taking the car up to redline and letting it naturally slow back down again, in hopes of cleaning out the injectors naturally. Repeat this maneuver several times for each gear while staying under local speed limits.

You can also take your car to the local racetrack to perform this type of tune up without worry about driving laws. No matter where you run, make sure you have all of your fluids topped off to the right levels before attempting to tune up your car by revving aggressively. After each run, listen to the injectors using a stethoscope to see if the noises evened out or quieted down.

Pressurized Cleanser

Pressurized fuel system cleaners rapidly send a strong solvent through the injectors in an effort to dissolve or dislodge carbon buildup in the nozzle. You can place this type of cleanser in the gas tank or suck it directly through the vacuum lines to clean the injectors from multiple points. When adding this cleanser to the gas tank, fill up and then add one ounce of cleaner for each gallon of fuel.

To feed it through the vacuum lines, locate the brake booster line for your vehicle. Feeding the cleaner through the brake booster cleans out the entire top end of the engine, injectors and all. To perform this task, start the car and then disconnect the main line from the brake booster. Stick it in the canister of cleanser for one second and reconnect to the booster. You should hear your engine rev up for a second as the high-octane cleanser makes its way through the engine.

Soaking With A Solvent

If the two above steps do not properly clean out the injectors, you will need to remove them from the vehicle for manual cleaning. You will need to soak the injectors in a bucket of solvent for at least 24 hours to dislodge crud built up inside.

Use a heavy-duty carburetor cleaner for the best results. Swish the injectors around in the solution a few times a day to push carbon and dirt buildup into the bucket. If the solvent turns a dirty brown or black color, replace it with new solution and put the injectors back in for another round of soaking.

Enjoying The Benefits

Once you have your injectors cleaned out properly, the proper spray pattern and flow rate will allow for perfect combustion in the chamber. Depending on your model year, the stock injectors deliver between 270 to 480 cubic centimeters of fuel per minute, with a three bar regulator, for a perfect mix of air and fuel in the combustion chamber.

If you upgrade any of your air delivery components, you can upgrade your injectors all the way up to the 740cc size or install a four bar regulator to increase the amount of fuel going into your engine. Work with a qualified shop to find the ideal injector flow rates for your unique build. If you're unsure about the benefits gained from injector service and upgrades, have your car placed on the dynamometer to measure power output before and after each change to gauge your progress.