Ins and outs of fuel-injector cleaners

Hey there, time traveller!
This article was published 30/10/2009 (5859 days ago), so information in it may no longer be current.

QUESTION: With our last car, the service department wanted us to add fuel-injector cleaner to the fuel at each oil change. We now have a different make and the injector cleaner is not mentioned. The engines in both cases were not high-performance. Does the injector cleaner help in any way and, if so, what brand would you recommend?

ANSWER: Fuel-injector cleaner helps keep injector tips free of gummy fuel deposits and also helps clean deposits off the back of intake valves. Valve deposits disrupt air and fuel flow, which can cause hesitations and decrease fuel economy. There are three ways to put fuel-injector cleaner into your vehicle.

The first and easiest way is to fill the vehicle with gasoline. Most gasolines contain fuel-injector cleaner as part of their mix, but some brands do have more and advertise their gasoline as containing injector-cleaning additives. Usually there is more in premium fuel than regular fuel.

Fuel-injector cleaner also comes from aftermarket chemical companies that sell it in consumer-sized containers. Usually, one container of cleaner is added with a full tank of fuel. The cleaner isn’t needed in every tank of fuel and you should never add more cleaner than recommended or it can damage rubber parts in the fuel system. I recommend adding cleaner occasionally for vehicles that spend most of the time in stop-and-go driving, idle a lot or drive at slow speeds. Vehicles driven mostly on the highway seldom need it.

A repair shop can run concentrated injector cleaner through the fuel system, bypassing the fuel tank so it doesn’t harm fuel-system parts. This is more of a repair procedure than routine maintenance, but it’s often offered as a service from repair shops to keep vehicles operating at peak performance. As for brands, I have tried many and they all seem to work fine, so choose on value.

QUESTION: I have a question for you about my daughter’s 2000 Hyundai Sonata. While driving down the road, her power steering went and then she had no power. After shutting the car off she tried to start it, but it wouldn’t run. She was told that it was her timing belt, but her belt isn’t broken. There was a smaller belt broken. We were also told that it could be a sensor. Thanks.

ANSWER: I am assuming your daughter’s car has the 2.4-litre four-cylinder engine in it, as the V6 engine uses a serpentine belt rather than a separate power-steering belt. A broken power-steering belt could cause the problems. The first symptom would be a loss of power steering. Usually, this is the only problem it would cause, but it’s possible for a small part of the broken belt to get under the covers of the timing belt and cause the rest of the problems there.

The timing belt is a notched or toothed belt that drives the camshaft from the crankshaft. The teeth on the belt match notches in the pulleys, so there is a positive drive that remains always in the correct sequence. If a small piece of rubber gets between the timing belt and a pulley, it could cause the timing belt to jump a notch and become out-of-time or sequence. If it is only one or two teeth out, the car would be difficult to start. If the belt is out-of-time by several teeth, the valves could come in contact with the pistons, bending them and requiring major engine work to repair it.

A simple test of crank-sensor operation is to remove a spark-plug wire and install a spare spark plug in it. Have someone crank the engine while holding the spark plug against a metal part of the engine. If there is spark across the spark plug electrodes, the crank sensor is sending a signal and you should be looking at timing-belt or fuel-delivery problems. If there is no spark, the crank sensor circuit is the most likely fault. Look carefully for broken wiring at the front of the engine and you may find the fault.

Jim Kerr is an experienced mechanic, instructor and member of the Automobile Journalists’ Association of Canada.

kerr.jim@sasktel.net