Each year, millions of dollars are spent on different cleaning methods for fuel injectors. The question now is which one among all works the best. To help our readers make an informed decision, we have performed a hands-on review for the most popular injector cleaning methods present for the general public.<\/p>\n\n\n\n
Having a load-bearing chassis dyno and an accurate air-fuel ratio analyzer available, we tried the most popular injector cleaning method. <\/p>\n\n\n\n
For this test, we used a 1993 Ford Mustang having 135000 miles, on an odometer. Before the experiment, the ca have not been driven for almost two months.<\/p>\n\n\n\n
To begin with, a leak down and a compression test was performed which resulted in a fine. The fuel tank was then drained. The fuel was nevertheless discolored slightly, but it did not have a bad odor and no indication of phase separation was present.<\/p>\n\n\n\n
The tailpipe was hooked up with an Autronic model B air-fuel analyzer, and 10 gallons of fresh gas was poured in the tank. On starting, the engine stumbled a bit but once it warmed up, it ran fairly smoothly. The throttle response was although fair but had some misfired under the free-revving. We then took the car on a road trip which included both an open road and some stop and go driving. <\/p>\n\n\n\n
The engine ran fairly smoothly on the cruise, but the Air Fuel Ratio was indicating constantly that it was running between rich and lean. Huge lean-rich fluctuations were displayed in the stop and go driving. Finally, the wide-open throttle acceleration produced certain misfires and was quite sluggish.<\/p>\n\n\n\n
The fuel tank emptied into a 5-gallon measuring can, back at the shop and 1.85 gallons were recorded. On the basis of this, 8.15 gallons of gas were used for the trip which was 102.7 miles and resulted in average fuel consumption of 12.6 miles\/gallon.<\/p>\n\n\n\n
Considering the engine size, fuel type and fuel injector size, etc. it was calculated that the car is able to produce 85-90 horsepower to wheels.<\/p>\n\n\n\n
5 gallons of fresh gas was entered into the fuel tank, and the vehicle then runs on a load-bearing chassis dynamometer. Lean engine conditions were indicated by the AFR ratios, and the vehicle then produced a horsepower of 72, which is approximately 15% less than expected.<\/p>\n\n\n\n
The old spark plugs indicated a lean condition when removed and checked. The new spark plugs gaping to appropriate size was installed once again and the car now produced a horsepower of 72. After this, the air filter was changed but again 72 hp. Following this, the fuel filter was replaced yet the car still produced just 72 hp\/<\/p>\n\n\n\n
The fuel pressure under load stayed at a constant pressure ranging between 43 \u2013 45 psi during a dyno testing, which indicated a healthy fuel pump. On the basis of these, it was felt that the fuel injectors were quite dirty and needed a cleanup. They were then removed and a flow test was conducted on them. the results were then 156, 168, 180, and 172 cc\/min.<\/p>\n\n\n\n
Fuel Injector Cleaner as the first method we put to test, which is also called injector cleaning additives. This cleaner is added and mixed to the fuel. The fuel injectors were then reinstalled without cleaning them, and the tank was drained. We added a good brand\u2019s fuel injection cleaner to the exact specifications mentioned by the manufacturer, with 5 gallons of fresh fuel, and was then poured in the fuel tank again. The cost of fuel injector cleaner was around $12.5. in a matter of just a few minutes after starting, we noticed that the engine was now running somewhat rougher than before.<\/p>\n\n\n\n
The car would now produce only 63 hp on the initial dyno pull, but it wasn\u2019t able to complete the second dyno pull as the engine started misfiring badly after bogging down. The AFR turned lean and indicated a 17:1 and above AFR.<\/p>\n\n\n\n
The engine was now unable to maintain idle and was to be kept alive just through additional throttling. The fuel injectors were now removed and put to test again, which this time flowed a 128, 162, 136 and 122. Moreover, two of the fuel injectors were leaking this time.<\/p>\n\n\n\n
The dirt in rail and fuel line is loosened while the injectors are partially clogged by the injector cleaner. They may be inexpensive but one should stay careful as it may also cause disastrous consequences. <\/p>\n\n\n\n
Now the injectors were reinstalled without being cleaned. This time a fuel rail was used with high pressure induced injector cleaner. This procedure may cost between $225 to $350 when done by an auto repair shop or mechanic. The engine managed to start without any additional input after the procedure, though once the throttle touched the engine would again die. The startup became tough and a smell of fuel was noticeable while cranking. In fact, strapping down the car on the dyno was just a waste of time.<\/p>\n\n\n\n
It was revealed during the injector flow test that the output was 142, 154, 146, and 128 but all four injectors were now leaking. It was noticed that two injectors had caused damage to filter baskets now. The remaining damaged filter baskets were now removed from the injectors and they were then proceeded back to flush them. besides the expected regular dirt, there was filter basket material present in the debris. The two injectors were again tested for leaks and flushed back. The flow increased to 168 and 180 this time with no leaks.<\/p>\n\n\n\n
The filter baskets on some injectors were damaged by the rail induced injection cleaning procedure. Debris chunks were forced past some injectors\u2019 filter baskets while some chunks were loosened from the pintle shafts. These chunks were too large to pass through the seat and pintle and were lodged between the seat and pintle leading to the leak in the injector. Meanwhile, the filter basket and debris of other injectors lodged between the pintle seats. This is exactly what was told to the dealer that was happening when the cleaning process was being performed.<\/p>\n\n\n\n
Without sidestepping the DIY cleaning process\u2019s proponents, we went into a 12V car battery with a syringe, carburetor cleaner, and a 12V auto battery with a push-type switch. The procedure was then followed as shown in some tutorials over YouTube. In order to ensure a thorough job was being done, the process was repeated around 5 times for each injector and then back to the flow bench. The results this time were 172, 174, 180, and 174 cc\/min. A slight improvement was noticed from the original flow test, which was quite small but not enough to warrant any additional dyno time.<\/p>\n\n\n\n
In our opinion, the DIY fuel cleaning methods can remove some of the loose debris but since the actual cleaning fluid does not remain in contact as much with the internal injector components for longer time periods, the baked hydrocarbons or and hard shellac cannot be loosened or dissolved by it.<\/p>\n\n\n\n
Finally, the fuel injector was put through a full ultrasonic fuel injector cleaning process. This injector cleaning method requires about 45 \u2013 60 minutes in the ultrasonic bath. Afterward, the injectors were flow tested, and this time the results were 192, 192, 194, and 192. New filter baskets and O-rings were installed. The injectors were installed using PTFE O-ring grease on the O-rings on both the manifold and fuel rail side.<\/p>\n\n\n\n
The gas tank was drained and 5 gallons of fresh gas were added and again we installed a new fuel filter. The engine fired up immediately and ran smoothly. Throttle response was good with no misfires. Free revving produced no misfires. Air to fuel ratios (AFR) stayed within 14.2: 1 \u2013 14.9:1<\/p>\n\n\n\n
The vehicle produced 87 HP on the dyno and AFR\u2019s stayed within an acceptable range during full power loads.<\/p>\n\n\n\n
Once again we drained all the gas and re-added exactly 10 gallons of fresh gas. We proceeded to complete the exact road and city trip we did in the beginning. This time we used 5.1 gallons of gas thus recording an average fuel consumption of 20.13 MPG. A fuel consumption decrees of 80%.<\/p>\n\n\n\n
Although fuel injection cleaners are cheap and \u201cmight\u201d work, extra precaution should be taken especially when used on older fuel systems. We recommend fuel injection cleaners for maintenance items and a precautionary solution on newer cars rather than a solution to cleaning fuel injectors.<\/p>\n\n\n\n
Based on our test on the above vehicle and subsequent newer models, a whole new range of variables are introduced when using high-pressure fuel rail induced injector cleaner. Some of these variables can have costly results. It is expensive and we do not recommend its use on older fuel systems. We also caution its use in newer fuel systems.<\/p>\n\n\n\n