I just got an oil change at one of the those quick change places. They suggested that they can put in some fuel additives for $50 to improve performance and economy. They said they will do a "fuel injection" and use a IV (like used by hospitals). Good idea or quack?

 

Unless they are pulling your injectors and putting them in one of those nifty cleaning machines that run them for awhile, its a waste of money.

Usually those oil changes places make very little on the actual oil change. They make up for it by charging you $50 bucks for $5 worth of work.

I'd smile at them and say "No thanks".

 

Run some Techron thru your fuel system about every 10,000 miles and forget the scam from those types of places. Better yet, do your own oil changes.

 

Actually, those FI system cleaners can be very beneficial.
However, it can be done too soon. At my shop, I relay the opinion that 75000mi is probably the point at which the vehicle driver will notice SOMETHING better after performing this work. Better idle, throttle response, mileage, etc. The further over 75k, the more likely there will be a difference. By that mileage, it is not a waste of money. The IV portion of this job gets into the intake, as well as cleaning the throttle body. Carbon does deposit in there. Idle air control motors get boogered up, and throttle plates start to stick because of it. After we are done doing all this, the more smoke that comes out of the exhaust, the more junk it cleaned out. This is sometimes all that is needed to get an ailing car back in good running condition again.
The stuff you pour in the tank will only go where the fuel flows. This goes further.
Again, this isnt something that needs to be done on a regular basis. And I'm not pushing it as such. It does have it place in automotive maintenance.

 

If you have the tools and time, it's still better and cheaper to pull parts like the throttle body and IAC Valve out and clean them independently. It can be done in an hour and for 10% of the cost that the oil place wants to charge.

Smoking out of the exhaust can simply be the engine burning the chemical used to clean the motor. Doesn't necessarily mean it's cleaning anything. Anything that alters the general 'good' mixture of air/fuel can cause it to smoke. Oil, water, too much fuel, as well as additives can cause an engine to smoke out of the exhaust.

 

Its always cheaper to do it yourself, no matter what the subject.
Like anything, if people feel it's over their head, they pay someone to do it for them. Today, I needed springs put on my garage door at home. $200. Torsion type springs, not the simple stretch ones. Worth it. Done in an hour. And I didnt lose a hand or head over it.
You are correct to an extant about the level of smoke. Having gone through many, many, many CASES of the 3 part, on a whole BUNCH of different cars, I can say the amount of crap that gets burned out varies from car to car. The level of smoke that comes out varies from car to car. Yet, the same amount is used each time at the same rate of consumption. The apparatus to dispense the cleaner regulates its flow, it is not poured in, as the home video earlier shows. The higher mileage cars, generally, have the most smoke, and the smelliest exhaust fumes. Not really a coincidence there.