False Economy Focus – A Case Study That Could Save You Hundreds!


What do I mean by a false economy focus? I mean that there is a still a perception with some people that it’s OK to buy the cheapest possible items. On paper it should make sense. You buy the cheap items, you save money, you’re on your way right? Unfortunately, life and cars are not this simple. There is a difference between an item that is cheap, and an item that is good value. At MotorKwirks, we are after the items that are good value. This could be either because they have been discounted from a higher price, or because they have a long life expectancy to offset the higher purchase price. There is an increasingly popular saying in the motoring world. ‘ Buy it cheap, buy it twice’. Allow me to explain with the latest example that affected me.

(Before we get into the details, don’t forget our 10% Referral Refund Scheme, for anyone who sends a customer to Motorkwirks Finder and Consultancy Services. Could you be the next to benefit?)

As you should hopefully know by now, I run a Mk1 Focus and in general the car is great, and doesn’t actually go wrong that often. It’s never once failed to complete a journey, ever. Even with me behind the wheel, it just keeps on going. However in late February, just before we were asked to stay at home, stay alert, and stay in bed or (whatever the phrase was back then), the car started to hesitate slightly as I drove along. Important note here coming up:

This device nearly ruined my holiday. But didn’t!

I changed most of the items in the engine to try and solve this. New spark plugs went in, along with new HT leads and a new coil pack. I changed the air filter, and the mass air flow sensor for a discounted one. You can probably see where this is going. I also cleaned out the throttle body, cleaned the battery terminals and even roped in my father-in-law to help me access and clean out the idle control valve. The culprit turned out to be the mass air flow sensor.

For those that don’t know, a mass-air flow sensor has an important role in the car. It tells the engine management system how much air is entering the engine, taking temperature and density into account, rather than just sheer volume. With this information, the engine management system can then ‘tell’ the fuelling system how much fuel the engine should receive. The ratio of fuel to air needs to be kept reasonably constant for the engine to run efficiently. Too little fuel for the air, the engine runs lean and we lose power. Too much fuel, the engine runs rich, engine damage could occur, and we waste fuel. So what was the issue?

Unplugging is only a temporary solution

In early March, I drove to France with the wife and in-laws, as mentioned in my holiday post. The car was still hesitating slightly. Luckily I had read on forums that if I simply unplug the air flow sensor, the engine would switch to a default mode and run better if the sensor was at fault. So I did this, and the engine did indeed run more smoothly. I left it unplugged all the way to France. And then the engine warning light came on. I had no idea what was wrong. The car was running better in the main so why was it complaining?

We continued into France, and tried resetting the car while we were there. The warning light went off for a few miles (enough to get to the supermarket and back with a car full of cheese). The light came back on the following day. I was now a bit worried. I’m quite particular when it comes to things like this, but I also didn’t want it to ruin the holiday. Countries were just starting to talk about the virus, so we had enough to worry about without the Focus starting to whinge as well. I decided to just put it to the back of my mind and attempt to enjoy the holiday since we didn’t know when our next one would be. But how would I find out what’s causing the car’s problem?

The car made it back from France in one piece, and we stopped off at the in-law’s on the way back home. My FIL is also very into his cars, and does a lot of the servicing himself. He lent me a diagnostic tool that plugs into the car’s computer. The computer then tells the tool what’s wrong with the car and what may need to be changed. In this case, it told me there was a fault with the airflow, as caused by the mass air flow sensor. When I plugged the old sensor back in, the warning light did not go away. So what’s the explanation?

There is now a more expensive version inside the focus. As there should be

You see, what I had done was replace an original life expired mass air flow sensor with a discounted one that turned out to be faulty. So of course, when the replacement took place and there was no improvement to the car’s drive-ability. This therefore made me move onto the next item to change. If I had bought the diagnostics kit to start with, I may have tackled the problem much sooner. But more importantly, if I had purchased a slightly more expensive air flow sensor, I would not have had this problem. The diagnostics kit told me the engine had been running too rich and too hot (probably because after 100,000 miles, default settings don’t always work).

My advice on the back of this would be to use reputable brands, and search for items that have been heavily discounted (from a high retail price). I would leave the cheaper brands alone. The sensor I had bought was actually advertised as a different brand. I was suspicious when I was handed the item, and the item brand didn’t match what was on the website. Once I’ve checked all my legal requirements, I will share the names concerned! This may have been changed since I made the purchase. I also recommend purchasing a diagnostics tool. You can buy them for a few pounds and will save a tonne of heartache. You can even get wireless ones that talk to your smartphone!

I ended up purchasing a replacement sensor from a different store, and the car has been much happier since then. My advice is to always spend the extra, especially when it comes to the engine. Normally, this is exactly what I do. The car runs on posh fully synthetic oil for maximum protection. I occasionally give it a tankful of super unleaded, for its (alleged) extra cleaning properties. The air filter is from a big brand, as is the battery. The plugs and leads are reputable too. It really pays to take care of our cars, so that they can take care of us. If you have any questions or comments about this false economy focus, feel free to join the family and get in touch. Thanks for reading!

What are your thoughts?