Ask the Mechanic

TOYOTA PICNIC 1AZ-FE VS TOYOTA WISH 1ZZFE

I would like to know the pros and cons of a Toyota Picnic engine 1AZ-FE 2000cc. Kindly let me know its fuel economy compared to, say, Toyota Wish 1ZZFE 1800cc, acceleration and toggle issues, as well as the current resale value of the 2003 model.

Hello, The 1AZFE 2.0 Litre (1998cc) engine in the 2003 Toyota Picnic (Ipsum) and the 1ZZFE 1.8L (1794cc) engine in the Toyota WISH are part of the revolutionary AZ and ZZ engines that replaced the renowned and robust Toyota S engines. The AZ and ZZ engines were designed with lighter aluminium engine cylinder heads and blocks, newer technology for electronic fuel delivery, variable valve timing of the air intake, electronic throttle and idle air control, double overhead camshafts in order to improve fuel economy, engine power and reduced emissions. This new technology gives these engines better fuel economy and performance. However, it also has challenges that affect the reliability of AZ and ZZ engines in different ways.

The 1AZFE and 1ZZFE aluminium cylinder heads were intended to reduce engine weight and improve fuel economy. However, they are susceptible to easy damage during overheating or failure of the head bolt threads during repair, necessitating costly replacement. This can be mitigated by periodically servicing the coolant fluid in order to keep the cooling system free of harmful corrosion and damage due to overheating. The fuel efficient continuous Variable Valve timing (VVTi) and chain driven camshaft timing systems improve fuel economy, performance and peace of mind. However, their reliability is challenged when the timing chain system and VVTi solenoid valves fail if you do not adhere to a strict high quality engine oil lubrication regime. You ought to use 5W30 fully synthetic or 10W40 semi synthetic reputable engine oil. These engines, at 80,000 -100,000 kms, tend to experience engine vibrations and loss of power at 500-600rpm. This is usually due to build-up of carbon deposit or dirt in the idle air control and throttle valves. This can be prevented by periodically replacing the air cleaner or cleaning the idle air control and throttle valves.

The fuel economy for the 2.0 litre Toyota Picnic and the 1.8 litre WISH is almost the same despite the different size engine (city:10 km per litre and highway: 15km per litre).

LEAVE THE J TURN IN THE MOVIES

 Some time ago I came across the phrase “J-turn” but did not think much about it. Recently, I heard the phrase again. What does it mean?

A J-turn is a tactic for turning a car through 180 degrees without pause in its speed or direction of travel. It is much favoured by Hollywood movie makers and stunt driving shows, and is taught as an “escape” manoeuvre to close protection officers (bodyguards) who chauffeur VIPs who may be in danger of kidnapping or assassination,

Trouble up ahead? Stop, engage reverse and go backwards at full speed. Then slam on the brakes and simultaneously turn the steering to full lock. The body of the car will skid-pivot around its back wheels. When it has started that pivot (which only takes a second) change to first gear, and when the car has rotated 180 degrees straighten the steering and accelerate.

The car will be going at about the same speed and in the same direction as the original reverse but will now be pointing/driving forwards and accelerating away from the trouble spot.

Getting it right takes practice, preferably starting on a purpose-built skid pan, then on a similarly large and open space with a grippier surface.

Handbrake turn

An equivalent manoeuvre for changing direction (but pointing forwards all the time) is called a handbrake turn. Trouble ahead? Pull on the handbrake and turn full lock. This breaks the traction on the rear wheels and the car will skid-pivot around its front wheels and come to a halt. While it is skidding, change down to first gear ready for an instant get-away in the opposite direction.

A version of this tactic is widely used in rally sport for turning at very tight hairpin bends. The gear change is often combined with turning on the windscreen wipers because the car will be turning (and proceeding) into its own dust.

Some principles of when to give way

 When two cars travelling in opposite directions both want to turn off into the same side road, which one of them has right of way? Is there a rule that governs all similar circumstances, and can, therefore, be taught and enforced?

Andrew

Hello Andrew, There are so many different case-by-case circumstances involved that there cannot be a single all-embracing rule to cover them. But there are some general principles.

The absolute first is a poem:

“Here lies the body of Edward Grey,

Who died maintaining his right of way.

His right was clear

And his will was strong

But he’s dead, just as dead,

As if he’d been wrong”.

Another is “Give Way To Cars On Your Right”. Like you do at roundabouts. In many situations, the sensible pecking order is obvious. An increasingly common situation where it is not is when cars turning left off a major highway enter a slip lane to decelerate just before the turn and a vehicle coming from the opposite direction is turning right.

 Both the principle and common sense point to “Give Way To Cars On Your Right”. The car in the slip road is safely out of the main high-speed stream and slowing down. The car turning right is crossing the main stream, and accelerating, with high speed traffic oncoming. It is more important that the car turning right is not obstructed, indeed, does not even have to hesitate.

 In many instances, all the traffic is moving slowly, and the “filtering” principle of one-for-one is the more rational procedure. The lesson in this that seems to escape the imaginations of many is that taking turns to give way in two intermingling streams is not a sacrifice. It allows both streams to keep moving and prevents a tailback which, in almost any urban context, ultimately blocks everything. Giving way to keep the flow moving not only helps the receiver. It also helps the giver.

So a fourth principle is: Use your common sense.

And a fifth is the mantra of the Institute of Advanced Motorists: “Care, Courtesy and Consideration”. Know about Rights of Way, but do not obsess about claiming them. Do what is safe. Do what is helpful.

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