Fuel injector cleaning


Do you guys think fuel injector cleaning is neccessary? doesnt the gasoline contain chemicals to “clean” the fuel injectors? I have worked a both Dealerships, independant and the inbetweens I dont want to mention by name but you know the guys who specialize in brakes but do other services the guys who specialize in mufflers but do other services the guys who are the service department for a up front retail store. Its these inbetweens who always pushed us to sell these cleanses or these flushes, but powersteering flushes and injector cleanings I wasnt convinced GM never tried to sell these things. Also what about the super oil changes where you were told (and the customer was charged extra) to put cleaning chemicals in the old oil,run the car 5 min. then drop the oil is there really any benifit to a car that has been kept on a current service plan? I do agree coolant needs to be changed but isnt drop and fill good enough?. What about selling new brake hardware (not just springs) with every brake job, nice but neccesssary?


Modern gasolines have a lot of cleaning agents in them and injectors normally don’t plug. Just had my wife’s 1994 car in for new plugs and I asked my mechanic (who builds dragsters and restores old cars as well) about injector cleaning. He said they seldom need this with today’s fuels,and he’s had cars in with ober 300,000 miles with the original injectors and never haveing been cleaned.


These services may be desirable in rare cases, those in which a car is showing specific symptoms. The problem is that most shops push these services on every unwary customer who walks through the door. Just say no.


These “services” are big money makers for repairers. That’s why the management wants you to push them, and that’s why they are generally a waste of money. The basic services like oil changes are frequently low profit teases to get the customer into the shop, where the employees are supposed to scare them to death that the car will die without a dose of Magical Mystery Motor Scrub, some turn signal fluid and rotate the air in the tires.


“Dirty fuel injectors” is one of those things that is frequently misdiagnosed. It ranks right up there with “cracked heads and blocks” and head gaskets; the latter also being frequently misdiagnosed.
All of these things irritate me to no end.

If one is curious as to whether an injector(s) might have a problem simply note how it’s idling. If an injector is acting up (even one with a poor spray pattern) the engine will idle rough or have a slight stumble, depending on just how bad it is.

I don’t normally consider new brake hardware an absolute must, but it all depends on the age/mileage of the vehicle in question. If the hardware shows signs of moderate rust it gets a new hardware kit. Most kits are only a few bucks anyway so why risk having a brake job come back (2 most evil words in the mechanic world) the next day with a broken spring.


How often is the fuel filter changed??? If it’s NEVER changed then it may lead to dirty injectors. But most likely this is one of those revenue adding services dealers charge.

The motor flushes are NOT needed unless you never change your oil and it’s really really dirty and sludge buildup. If you change your oil regularly it’s NOT necessary.

I agree with OK in that it’s probably cheap insurance…but most of the time it’s probably NOT necessary. Now the question you have to ask…are they really replacing all the hardware with new or just cleaning it all up and charging you for it??? Probably the latter.


The most frequent problem that I have run into with injectors is that the electrical signal to one injector is not acting right. The 8 times that I did checks on injectors was always a very low on non-existent resistance reading on only 1 injector. All other injectors on all engines were fine–all within specs. This can easily be checked simply by, one at a time, remove the two or three wires off of each injector and doing a resistance check on each injector. You’re checking the internal resistance of the injector so you don’t even need the engine to start or run. Those wires are clipped on in different ways, but those clips are all fairly simple to get off without breaking anything. Any repair manual that covers your year, make, model, engine has the resistance specs. for the injectors. They’ll also have what type of clip your car/engine uses and how to properly separate the clip/wires from the injector contacts. Then you need a simple V.O.M. (volt/ohm meter). Try to do this with a cool or at least just warm engine. Whoever does these injector checks will be setting right over that hot engine. That is not a pleasant experience.
Today’s fuel additives are adequate for keeping your injectors clean. Changing out the fuel filter, (no, it’s not the fine mesh screen in the tank connected to the fuel pump), as per manufacturer’s recommendations is a good idea, always. See above about my experiences with injectors. I’ve never run into a “clogged” injector.

All brake jobs, especially drum/shoe parts, should have all new hardware for each wheel. Just ask for the old parts back. Now there are still a couple of ways that unscrupulous shops can get away with not putting in the whole new kit, but just you asking for the old parts back almost always sends red flags up to the shop that they’d better do an honest, dependable and correct job as the shop doesn’t know whether or not you’re an undercover consumer advocate inspector or a reporter, or if you might be from a State agency, (State A.G., D.M.V., annual vehicle inspection investigator, whatever!) or you might simply take it to another known reputable shop for a post-repair inspection. They don’t know, but I’ll bet the hairs on the back of their necks will stand straight up!

Unless you have a bunch of sludge as mentioned by MikeInNH, engine oil system flushes are not necessary or needed. If you do let the oil/filter changes get away from you, then there are less expensive ways to flush the engine’s lube system. That is so rare that I won’t go any further unless requested to explain. (By the way, Mike, where in NH? I’m formerly from Nausea. OOPS! Freudian slip–Nashua).