Monthly Archives: November 2016

Vehicle maintenance steps

“The thought of a breakdown, an engine not starting or otherwise being stranded is scary as it is, but those things happening in freezing winter weather adds another level of fear,” said Rich White, executive director, Car Care Council. “An investment of an hour or so to have your vehicle checked will pay off and help make sure your winter driving is less frightful and more delightful.”

The Car Care Council recommends the following steps for winterizing your vehicle:

  • Check the battery and charging system for optimum performance. Cold weather is hard on batteries.
  • Clean, flush and put new antifreeze in the cooling system. As a general rule of thumb, this should be done every two years.
  • Make sure heaters, defrosters and wipers work properly. Consider winter wiper blades and use cold weather washer fluid. Typically, wiper blades should be replaced every six months.
  • If you’re due for a tune-up, have it done before winter sets in. Winter magnifies existing problems such as pings, hard starts, sluggish performance or rough idling.
  • Check the tire tread depth and tire pressure. If snow and ice are a problem in your area, consider special tires designed to grip slick roads. During winter, tire pressure should be checked weekly.
  • Check the brakes. The braking system is the vehicle’s most important safety component.
  • Inspect the exhaust system for carbon monoxide leaks, which can be especially dangerous during cold weather driving when windows are closed.
  • Check to see that exterior and interior lights work and headlights are properly aimed.
  • Be diligent about changing the oil at recommended intervals as dirty oil can spell trouble in winter. Consider changing to “winter weight” oil if you live in a cold climate. Check the fuel, air and transmission filters at the same time.

Motorists should also keep the gas tank at least half full at all times to decrease the chances of moisture forming in the gas lines and possibly freezing. Drivers should check the tire pressure of the spare in the trunk and stock an emergency kit with an ice scraper and snowbrush, jumper cables, flashlight, flares, blanket, extra clothes, candles/matches, bottled water, dry food snacks and needed medication.

Automotive Master Technician

Every sensor on or in a computer-controlled car or truck talks to the “on-board PC” in a kind of language you’ve never heard or seen. All of the inputs are in a voltage-speak and are all numbers. All of these signals to and from the PC travel in and out at up to 300 times per second. That is some party line!

Your PC knows the amount of air going into or being inhaled by the engine. It knows the temperature of the air, the barometric pressure, the outside temperature, if it’s raining and if the engine is pinging. It knows if the engine has too much fuel or too little fuel being delivered to it. It knows the temperature of the coolant and the catalytic converter, and it knows how cold it is inside the car and how that compares to the temperature you are requesting.

Most of the voltages start at zero and have a high end of 5, 8 or 12 volts. For instance, 1.0v means low and 5.0v means high. Or 1.0 means cold and 5.0 means hot, hot, hot.

But most scanners convert these numbers to a range we can understand, like 20 grams or 212F or 45% throttle.

The mass air flow sensor (MAF) tells the PC how much air is flowing into the engine; we read that data in grams. So a little air means no foot on the throttle and lots of air means foot to the floor. Think of the mass air flow sensor as a goal post with a filament across the top arms. It actually looks like the filament inside a clear light bulb.

The PC sends voltage to the filament and then monitors the electricity needed to keep it warm or hot. The MAF starts lying when this filament gets covered with trash, bugs and dirt. Pretend you are in a tunnel and naked. You could easily tell how much air is flowing thru this tunnel and what the temperature is. How good of a job could you do if I covered you with 5 layers of clothing, gloves, hats and full face coverings? That is exactly what happens to your MAF: it gets covered up and starts lying about its environment.

We want to see about 5-10 grams depending on the size of the engine. This gram number determines fuel trim. A dirty MAF won’t see all the air, so it tells the PC to trim the fuel down. 1 gram at idle is a problem.

So if you want to save yourself from $45 to over $100, go to the auto parts store. Ask them to point out where the MAF is located on your car, and ask them to show you what it looks like. You may need special tools. Then buy some CRC Mass Air Flow Sensor Cleaner. The CRC product was developed specifically for cleaning this very delicate sensor.

Pull the negative battery cable. Remove the MAF sensor. DO NOT touch the filament. DO NOT get your wife’s toothbrush out and scrub it. If you damage it, you just cost yourself hundreds of dollars. Just spray it off like you would spray a small painted wire with carburetor cleaner when you only want to remove the paint. Do it maybe 3-4 times and once every 30-40,000 miles.

Let it dry, reinstall, connect the battery and drive away. It will take the PC just a few hours to reset those parameters that just changed because the MAF is now cleaner and working more precisely.

Car may not be cooling fast enough

If your car’s A/C system is not cooling you off in a reasonable time frame to make you happy, take it to your service professional for an A/C check-up. Here’s what he or she will look at: • Is the compressor weak? It may build up pressure slowly, or require high rpm to produce normal pressures, so it takes a while to produce adequate cooling. A pressure test should indicate this problem. • Outside air flap not closing. When the system is in Max A/C, the flap should be closed. Unless the flap is closed, hot outside air dilutes the effect of A/C, producing slow cool down. • Is the temperature (blend-air) door operating correctly? This doesn’t have to be an either-it-is-or-it-isn’t proposition.

 

If the temperature door isn’t in the Max Cool position, the heater core may contribute enough heat to slow down the cooling. Eventually, particularly when the system is set in Max A/C, the A/C may overcome a small heating effect. Even if there is a heater coolant control valve and it’s fully closed, a temperature door even just partly in the wrong position can slow down the cooling by redirecting some of the airflow through the heater. • Heater coolant valve failing to close completely, if at all. The temperature door may be in the right position, but on some systems hot coolant in the core still contributes enough heat to the HVAC case to slow cool down. • Is there a problem with the radiator fan? If it’s a clutch fan, it may be engaging late. If it’s an electric fan, it may be coming on late. In either case, the effect is to reduce airflow (thus affecting cooling), particularly in low speed driving and idle operation.

 

When the fan finally engages or comes on, the condensing improves and the A/C cooling improves. • Was the system retrofitted? We’re certainly not against retrofit, and we know it’s commonly done when an old compressor fails. But too often, the only parts replaced are the compressor and receiver-dryer, or the compressor, accumulator and orifice tube. On a system designed for R12, unless you do a complete retrofit, performance may be measurably lower. We all know there are many systems that just don’t do well with a basic retrofit, even if it includes a compressor replacement. • Any HVAC case air leaks? If the seals between the case and the cowl are deteriorated, hot engine compartment air gets blown into the case and the passenger compartment. It can take a really long time for the A/C to overcome that. • Slightly low on refrigerant. With some of today’s lower capacity systems, this can account for a huge difference in performance. Today, most systems have capacities of 14 to 32 ounces, so a five-ounce loss is substantial. If this sounds technical and complex, it is!