Ask the Mechanic

WHY DOES MY CAR HAVE POOR FUEL ECONOMY?

Hello Paul, I recently bought a 2009 Toyota Premio 1.8L AWD but I am worried about its fuel consumption. On the dashboard, it is registering an average fuel consumption of eight to nine kilometers per litre.  I replaced the air filter, spark plugs, engine oil and got wheel alignment done, but the highest it has reflected on the dashboard is 10kms/litre when going downhill. The car is also slow when going uphill but gains speed on flat terrain. What could be the problem?  Dennis Muriithi Kubai.

Hello Dennis, the Toyota Premio 2009 with super CVT transmission and 2ZRFE 1.8 litre petrol engine should give you a fuel consumption of  17kms/litre or better depending on your driving style, use of efficient fuel and engine maintenance or running condition. Your car’s sluggish performance while driving uphill may have a direct link to the poor fuel economy you are experiencing.

While you have made an effort to carry out most of the regular maintenance requirements such as oil and filter service, air filter and spark plugs, you may need to consider servicing the fuel filter.

A clogged fuel filter will affect the fuel pump performance (fuel pressure delivered) or even damage it. This will have a noticeable effect on car performance, especially during uphill drives.

Restricted fuel pressure affects engine performance and to a great extent, leads to inefficient running as you need high revs to build engine power. There are engine management sensors such as the air flow metre and the oxygen sensor whose failure to perform can cause poor fuel economy.

These sensors help the engine computer to regulate fuel delivery, which has a direct link to fuel economy and performance uphill (especially the air flow metre).

A computer diagnosis can help confirm this.

IS MY CAR STARTER MOTOR FAULTY?

Hello Paul, I have recently acquired a locally used Toyota Ipsum 2002 model. Lately, it fails to start and only makes a click sound when I turn the key. Is the starter faulty?

Kabagambe

Hello Kabagambe, before you conclude that the starter motor is faulty, first check power supply and contacts. The battery terminals must be free of corrosion and tightly fastened. You will need a good car electrician to inspect the starter motor circuit, which includes the relay and connections to its power supply terminals. The other cause of a starter motor failure is a faulty solenoid.

You will rarely find a damaged or corroded circuit affecting the solenoid. If the solenoid is fine, the starter can be dismantled to inspect the starter brushes, which are supposed to make contact with the commutator. It is common to find that a faulty starter motor just needs a replacement of the contact brushes. The electrician will decide whether your starter motor can be repaired or not. A quality, used one from engine breakers is your next affordable option.

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