What is a TPS? (Throttle Position Sensor)

You know you have an accelerator pedal; step on it and your vehicle is supposed to go.  But did you know there is a part in your vehicle that keeps track of where the throttle is? It’s called the Throttle Position Sensor, or TPS.

The TPS is a sensor that helps your vehicle figure out the right mix of air and fuel is reaching your engine.  It does that by keeping track of the throttle and sending that information to your vehicle’s computer.  Other factors play a role in how well your engine is performing, including air temperature, how fast the engine is turning over and air flow. 

When the TPS isn’t working right, you may find your vehicle won’t accelerate or doesn’t have the power you’re expecting when you press on the accelerator.  In some cases, it may accelerate on its own.  Sometimes your vehicle won’t go over a certain speed.  Your Check Engine light may go on.

Any of these symptoms should be checked out soon.  If your TPS stops working right, your vehicle may not be safe to drive.  Fortunately, most vehicles have a “limp home” mode that will allow you to get off a busy road to a safe spot. 

Your service advisor can let you know which TPS is the correct replacement for your vehicle.  Your shop may have to re-program the new TPS so it works correctly with other software in your vehicle.

It’s a fact of life these days that computers control many of a vehicle’s functions. The sensors that feed information to those computers help make your vehicle work the way it was engineered to and keep you motoring down the road safely and efficiently.

Autotronics of St. Peter
111 Jefferson Avenue
St. Peter, MN 56082
507.934.9290
http://autotronicsstpeter.com

Before You Buy that Used Vehicle (Having a Used Car Inspected Before Buying)

Let’s face it.  New vehicles are expensive, so finding a good used one can save drivers a lot of money.  It’s tempting to look through ads, find a private seller who has what you’re looking for and pay a price you think is a great deal.  But when you go over to look at a used car, do you really know what to look for to uncover potential problems with it?

The answer is probably no.  Used cars can look great on the outside, maybe even have lustrous paint and a super clean interior. But is it possible that vehicle’s been in an accident? Does it have electrical problems you can’t detect easily? Is any fluid leaking that you don’t know about?

Think about it.  You are about to spend thousands of dollars for a complex machine and you’re considering judging its condition without much expertise.  That’s why it makes sense to have a qualified technician inspect any used vehicle you’re considering buying.

Many vehicle repair facilities will do it for around $100-$200.  They’ll check to see what’s working right and what’s not working.  They’ll check for leaks and how strong the battery is; they’ll look for signs it’s been in an accident or has been painted. They’ll look in places you’d find inaccessible, and they’ll take it for a test drive to see what noises, vibrations and smells might give clues to any major problems.  An inspection usually takes about an hour.

You should have an inspection done by a technician you know and trust.  They’ll have your best interests in mind.  And the inspection should be done before you start negotiating a price with the seller.  It’s money well spent to either give you peace of mind that you’re getting a good vehicle or steer you away from a lemon. 

One sign a used vehicle isn’t a good deal? If the buyer refuses to let you have it inspected.  That says just about everything that needs to be said.    

Autotronics of St. Peter
111 Jefferson Avenue
St. Peter, MN 56082
507.934.9290
http://autotronicsstpeter.com

Don’t Start with That (Bad Starter Motor)

We’ve all heard that expression, “That’s a non starter.” When it comes to your vehicle, that’s not music to a driver’s ears. That sickening sound when you start the ignition and instead of hearing the engine crank, you hear it slowly turn over and your dash lights go dim. 

There can be many reasons a vehicle won’t start, so here’s a little history of how the starter came to be an important component of modern vehicles.

You have to move the engine’s components to start it. The first cars had a crank that the driver would insert into the front, then start turning things over by hand.  When the engine started, you had to release that crank immediately or risk a broken arm.  Yes, it happened many times.  So, they came up with a better idea: an electric starter, which was a big advance in automotive technology.

With this system, an electric motor rotated a series of gears that turned the gasoline engine’s crankshaft so its pistons and parts moved and the engine drew in air.  While this happened, electricity went to the spark plugs and fuel headed to the cylinders.  When the gasoline engine caught, the starter quickly disengaged. Hey, no more broken arms!

Modern systems use the same principle, so when your vehicle won’t start, here are a few things to look out for that might point to the starter. 

If the engine turns over s-l-o-w-l-y, it may mean the electric starter motor may just be wearing out and doesn’t have enough cranking power.  Bushings, brushes, wire windings and a special switch called a commutator may be going bad.

If when you engage the ignition you hear a faint click, that could be a symptom one or more of the starter’s components have failed. If you hear a loud click, it could mean that an electrical switch called a solenoid may not be switching the motor on.

If you hear your engine start to turn over but then it stops and is followed by a grinding sound, some gears may not be meshing the way they should.

There may be many more causes (bad alternator, relay, battery, engine, key fob), so this is when it’s time to turn it over to your service facility.  Sometimes they can send out their own tow truck or recommend a reputable towing company.

But it’s best not to let it get to this point.  Starter problems often give you advance warning that there is a problem with “almost” not starting or “almost” not turning over.  So when you see that very first sign, “start” on over to talk this one over with your service advisor.  The opposite of a “non-starter” is a starter, and that is music to anyone’s ears.

Autotronics of St. Peter
111 Jefferson Avenue
St. Peter, MN 56082
507.934.9290
http://autotronicsstpeter.com