JM Baraza: Stop believing these fuel saving myths

Good afternoon,

I am a zealous reader of your articles. To me, you are a superman of cars. Let me say you are an expert. My questions for today are:

1. Does filling a car tank, especially while stepping on the metal stand, reduce fuel consumption?

2. And is it true that when the tank is full, the consumption reduces?

3. Is it advisable to fill the tank while stepping on that metal?

Thanks,

Brian Bakanjo

Hi Bakanjo.

Thanks for the glowing accolades; I can’t get enough of them.

1. No, it doesn’t. Not at all. Never.

2. No, it’s not. Not at all. Never.

3. No, it’s not. Not at all. Never.

Let me explain a few things here: fuel consumption depends entirely on where and how a vehicle is driven, not where and how it is fuelled. Other secondary factors that will determine fuel consumption are the mass of the car (load on board), condition or roadworthiness, use of accessories such as air conditioning, and whether or not the windows are open (aerodynamic profile).

As to the fullness of the tank, the consumption will not reduce. Scientifically, it should increase because a full tank means more weight, and as we saw in the preceding paragraph, weight is the enemy of consumption. However, the difference between a full tank and an empty one could be as little as 36kg for a small-ish car (or one with a tiny tank). The effect 36kg has on the fuel economy, especially in engines with four-figure displacements, is negligible and can easily be undone or overcome by adjusting driving style or switching off the AC for a few minutes.

Filling the tank while parked on a ramp is a Chinese fire drill, a lot of effort accomplishing nothing. Matatu drivers, holders of doctorates in automotive engineering and geometrical meisters that they aren’t, will argue passionately for it, and the basis of their aggressiveness will be this: they have driven matatus since before your dad met your mum, so “shut up, kid. You know nothing”.

They’re the ones who know nothing. The fuel tank is always below the fuel filler pipe, meaning if you fill up the tank to the nozzle cut-off level, the tank is as complete as it will ever be. No amount of gymnastics is going to create space where none exists. Parking on a ramp to fuel your vehicle is exactly like wearing a lab coat and placing ballpoint pens in the breast pocket to look like a STEM practitioner (Science, Technology, Engineering and Mathematics, for the roomy-skulled). It serves zero purposes besides pointless visuals.

Honda CR-V, Mazda Cx5 or Honda Vezel for Sh2.5million?

Hello Baraza,

First things first. I know zilch about cars. Yes. I know that isn’t good for a grown-up man to admit.

However, I own a 2013 Honda Fit that has served me very well for the last 3 years without ever breaking down. I have never been to a garage other than for the routine service.

I am now considering upgrading. My budget is a maximum 2.5M.

I am considering a Honda CR-V, Mazda Cx5 or Honda Vezel

I know you have done some writing on CRV/Mazda, but I still want to hear your take.

Alternatively, which decent car can I get for that budget? Reliability is my topmost concern. Certainly not aesthetics.

Would you mind hiding the embarrassment of not knowing about cars by using my initials JM in the newspaper?

Hello,

I see you are proactive about hiding your embarrassment. You didn’t sign off on your message, so I don’t even have initials to use, let alone a full name.

Yes, I have done a bit of writing about the CRV and the CX5, and my take is the same as the others: the CRV is reliable (somewhat), while the CX5 is pretty and pleasant to drive.

A decent car for that budget would be a RAV4. It ticks the same boxes you are keenest over: reliable and not necessarily pretty. Bang on! It has the bonus of being in the same crossover segment as the Honda and the Mazda while countering their USPs by packing them in its repertoire. The CRV’s advantage over the CX5 is seven-seat potential, huh? The RAV4 has a priapic twin called the Vanguard. The CX5 is pretty and pleasant to drive, huh? Well, er.. the RAV4, hmmm, aah... the RAV4 is reliable. So there! Moving on

Get a RAV4.... or a Vanguard

Why does my car have trouble going uphill?

Dear Baraza,

Thank you for always taking the time to respond to your readers’ questions and doing so with great humour while at it.

So the other day, I was driving up the hill from AIC Cure Kijabe Hospital and, my car dragged itself uphill. I was even overtaken by a loaded minibus. I have on previous occasions noticed this behaviour, and a mechanic once told me that the engine was choked and therefore I needed Cat regeneration.

Of course, he has given me a huge bill. My dad, who is quite advanced in age and the driving experience, was quick to caution me against spending that considerable amount of money but unfortunately never gave me a solution. He ideally is not very concerned, noting that most of my driving is within Nairobi.

So here I am, hoping to get some answers from the guru.

Thanks and Regards,

Catherine

Dear Catherine,

There is a lot to unpack here, to be honest. Let’s start with the fact that power loss from an engine could result from any of a thousand different occurrences in the car. The loss of power doesn’t even have to have an under bonnet cause; things like clogged fuel filters or failing fuel pumps could contribute to this.

That means I don’t have an answer for you unless and until I see the car because guesswork by correspondence serves no purpose besides filling space and wasting paper. Some ailments can be narrowed down to a few possible suspects, but others like power loss have a list of causes too long to exhaust comprehensively.

Your dad is right, don’t cough up any cabbage unless and until the problem is solved. It could be the cat needs de-clogging, but I seriously doubt it. Ideally, the cat should regenerate itself somewhat. If the mechanic says the engine was choked, perhaps he should have started with the air cleaner, but since he made a beeline for the cat and brandished a massive bill to boot, I wouldn’t trust him as far as I can throw him, and I have never thrown anyone since I left high school.

It would help if you had another mech, one less knavish. I don’t do motor vehicle repairs, though I do diagnostics in my spare time. Find a way to find me then we see if we can resolve your loss of power.

I want to buy the Mercedes you wrote about

Good afternoon,

In your article in the Daily Nation on August 18, 2021, you mentioned that some

units costing around 0.7 to 0.9m had come across your desk. Do you mind sharing the contact details of the sellers? I’m an avid reader of your column and currently looking for a well-maintained car within this price range.

Thank you.

Kind regards,

Elizabeth

Hi Elizabeth,

See me in my office (my editor will share my contact details with you summarily...)

I am not allowed to share the contacts of sellers of cars here for two reasons: that is advertising that they have not paid for, and secondly, for some of these, the contacts are their private lines, and I wouldn’t want them inundated with phone calls when they’re trying to get some sleep.

Like your lady friend above, find a way to find me, then together we’ll find these friends who sell W140s at prices below seven figures. You won’t be disappointed.

What’s your take on the Honda Stepwagon?

Hey Baraza,

I’m kindly requesting a review of the Honda Stepwagon, the Noah/Voxy look alike,

I was checking on the prices, and the difference is enormous.

I want to use it for airport transfer services.

Thanks

Mbogo W.

Hi Mbogo,

Yes, the price difference is noticeable between a Noxy/Voah and the Honda What-Is-A-Vowel-Anyway. I have reviewed and compared these vehicles before, and we found that the winner is a Toyota Alphard. If you do airport transfers, you want to look important, and you want to give your passengers the sensation of being in a commercial airliner even before the boarding call is made. It doesn’t get any closer to an aeroplane than an Alphard, for size if not for anything else.

The Stepwgn is OK for airport transfers. The occupants won’t be in it long enough to let its inherent weaknesses get on their nerves, and as the operator, whatever sticking points you find can be easily overcome by meditation. Adopt the lotus position, touch your middle fingers to your thumbs forming little circles at the end of your partially outstretched arms, close your eyes and chant repeatedly: “The price difference is huuuuuge.... the price difference is huuuuuge... the price difference is....”

You will recover quickly from your hangups.

Case of my wobbly Toyota Harrier

Baraza,

Why is my Toyota Harrier constantly wobbling when I apply brakes when doing 100km per hour even after replacing almost everything within the braking system and doing both alignment and wheel balancing?

F.K. Njuguna.

Njuguna,

What exactly does that mean when you say you have done “almost everything within the braking system”? My list of potential causes comprises exclusively of braking system components, so how do I know not to ask you to repeat something you have already tried?

The most apparent cause of the vibration would be warped brake discs, and the only cure for them is a replacement.

Other causes are the tyres. You have done both alignment and balancing. Guess what? Could you do it again?

The rims could be bent, it could even be a bad front shock absorber, or some suspension gubbins are either missing or need repair/replacement, a wheel bearing may be faulty, or the problem could be in the steering rack. You have a lot of diagnoses to do; I suggest you get cracking. At least you know which end of the car to look into, unlike Catherine who’s problems could be stemming from anywhere...

Got a motoring question? Email [email protected]