If your engine cuts off in motion, most likely cause is vapour lock

I am an avid reader of your column and finally,  here I am with a problem.

I have a Toyota Runx whose problem is the engine cutting off  when in motion. This happens frequently, sometimes three times on a 50km trip. I have been to several mechanics who have tried changing the fuel filter, cleaning the throttle as well as the sensors, all in vain. What could be the problem?

Julius Ouma

 

Hello Julius,

The information you submitted is very sketchy, but we will still give it a shot. An engine cutting out while you’re driving is most likely a victim of vapour lock, caused by excessive heat in the engine.

So, does the stalling occur only when the engine is abnormally hot? If yes, then vapour lock is the culprit.

The excessive heat boils the petrol in the fuel lines, causing bubbles within the liquid and thus the engine runs lean, that is, there is not enough fuel in the intake charge; the air:fuel ratio is off.

Since the engine can’t run like this for long, it stalls every now and then. If the engine temperature is within the normal operating range — and given that you have fuel injection — then the cause of the stalling could be a faulty fuel pressure regulator.

 

I sometimes read your articles and I must say they are educative.

I bought a Toyota Avensis 2008 model in June 2015. When I took it for the first service, the mechanical report showed that it needed a new starter as well as a strainer. I decided to wait on the strainer.

I now feel that the vehicle does not have power. In addition, the brakes are too low and irrespective of how much the mechanic adjusts them, they still remain low.

What should I do? This is my first car.

Jullie

 

Hi Jullie,

The lack of power could be from the need of a new strainer. I believe by “strainer” you mean filter, and by filter I mean the fuel filter since it is the part of a car that most resembles a kitchen strainer.

The filter might be clogged, which in turn means it is not allowing enough fuel through to get the car to reach higher revs (engine speed).

The car thus feels strangled and underperforms. Similar symptoms can also be experienced with a clogged air filter, but this should have been sorted during one of the regular service procedures. You do take

your car for service, don’t you?

What exactly do you mean the brakes are too low? Can’t your feet reach them? You do know that the driver’s seat (as well as the steering wheel) is adjustable to cater for all sorts of body types, don’t you?

If you can’t reach the brake pedal, perhaps you could try moving the driver’s seat forward? One cause of a “low” brake pedal is low levels of brake fluid within the braking system, but this is typically accompanied by reduced brake force at the wheels (the

car takes a longer distance to slow down compared to before), as well as a spongy pedal feel. If the fluid levels are so low that the brake pedal sinks to the floor, you probably wouldn’t be sending me an email right now (Crash, smash, weep, weep!).

I’m assuming your mechanic is intelligent enough to have thought of that before he started adjusting the pedal position.

My apologies if I sounded condescending or patronising. Being a first-time car owner, keep it here for general advice and helpful, handy tips and hints on how to keep your car from causing you grief.

 

Hi,

I love your column on car-related issues. I live in London and am considering buying a Vauxhall Insignia because it’s cheaper here. I plan to use it when I am in Kenya, and that is twice a year. I would like your advice on this.

Moses Papilito

 

Hello Papilito,

The Insignia is a nice car. It even won a Car of The Year (COTY) Award in Europe. That said, COTY awards typically go to brand new cars for setting one benchmark or the other, and they bear no reflection

of the real-world, day-to-day operations of that car.

There could be the option of visiting some Internet forums to find out if they have recurrent problems but that will not solve much: the vehicle might run fine in Europe but once it gets to the third world, the engineering in it starts showing its weakness at the most unlikely of places. The car was never sold here new, and I don’t think anyone has imported one yet, and if they have, they haven’t had it long enough to discover its loopholes.

  1. The Car Itself

That said, do not feel smug or rejoice yet in considering a COTY winner. The Insignia forums might contain only isolated incidents — the most recurrent being electrical gremlins — but I did manage to get hold of a technical service bulletin (TSB) from Vauxhall about the Insignia and… well, fire extinguishers are not very expensive, are they?

Let’s just say that a TSB is an “undercover” recall. We’ve discussed recalls here before, the most famous being Toyota’s stuck-throttle, self-acceleration issues and the Ford vs Firestone Explorer-rollover debacle.

Most recalls are publicly announced and followed up keenly by manufacturers; in some cases, they’ll even hire private investigators to find you if you refuse to give back your car for rectification, lest your car

kill you and your family sue the company for more money than any life insurance policy could ever accommodate.

With a TSB, the recall is done more quietly, without the knowledge of the general public, and is not a recall per se. It is more a silent switching of faulty parts before they fail, usually during normal service and

mostly under warranty, sometimes even without the owner’s knowledge.

The company sends an internal memo or private notice to dealers and garages to replace parts or the faults as soon as humanly possible for a particular set of affected vehicles.

What the owner does not know won’t hurt them.

Vauxhall’s TSB, dated October 2011, specifies that the pressure pipe that carries power steering fluid is susceptible to cracks and leaks due to “insufficient design”. The remedy was, or is, to replace the power steering pressure pipe and clip.

I remember removing the one in the Mazdalago at one point, an aluminium pipe that snaked its way around the right headlamp, because it, too, had a leak and welding looked like too much work. So I just

bypassed it and connected the reservoir straight to the pump.

Loss of power assistance for the steering is a bit dangerous, but is not something that cannot be overcome with a little presence of mind and a lot of forearm effort when parking. That was not the extent of Vauxhall’s potential problem.

The real danger lay in the leak itself: being a high-pressure line, a leak would be more like a spray if the aperture got big enough.

That spray could get to very hot engine parts, such as the exhaust manifold or the diesel particulate filter (DPF) in diesel cars. Power steering fluid is an oil, and oils are flammable. You can see where this is

going: conflagration.

Did I say potential problem? I meant actual problem, because there is a car that caught fire, which in turn is what prompted Vauxhall to issue the TSB in the first place. BBC carried a story about a man and his

wife  who were driving in their 2010 Insignia when the car (long story short) got written off in a roadside case of self-barbecue.

Vauxhall commissioned a forensic report which  concluded that the fire was fluid based, identifying stains on the DPF as the probable cause.

The report ruled out fuel or engine oil and hinted at power steering fluid being the responsible accelerant. However, Vauxhall later backtracked and said no such thing happened; there was nothing wrong with the pressure hoses or their fittings, and that the

cause of fire remains “unknown”. This was an interesting outcome, keeping in mind an earlier phone call between the badly shaken couple and the company.

Even before the report was commissioned, Vauxhall explained to the man on phone that the dramatic flame-out was because the pipe on the power steering had come off, dropping fluid onto the hot DPF. Vauxhall then said they have no content of the alleged

phone call between them and Martin Webb (the poor, fire-afflicted Insignia driver), hence their conclusion that the cause of the fire was “unknown”.

There are a lot more facets to this case that we will ignore for now, but Vauxhall’s TSB affects 6,900 vehicles, all of which were manufactured in Germany between 2009 and 2010. I haven’t been able to

acquire the VINs of the affected vehicles so that you can eliminate them from your search (I’ll look harder, I promise). About 63 per cent of the 6,900 vehicles have had the problem rectified, but this still raises a question: the cars were manufactured in

Germany, yes, but Mr Webb was in England (driving to Dorset) in what I presume was a UK-registered Vauxhall when the car caught fire.

Also, Vauxhall specifically said that his car was not part of the TSB lineup, but how does that absolve them in any way if it still underwent the very disaster that the TSB later tried to avert?

You can still get an Insignia, though. The reviews are very encouraging, with the focus being on reliability. My advice would be to go through a particular vehicle’s history to find out if it had been part of the recall and if it hadn’t, to replace the high pressure

hose and clips as a pre-emptive measure. Check the electricals too; as I said earlier, they can be an annoyance (sometimes the mirrors won’t retract and such).

  1. Your schedule

Then there is the “twice a year”. Twice a year could mean anything: it could mean twice in 365 days in which only hours are spent around on those occasions, or it could be twice annually in which each stint

lasts several months.

Which is it? If the car stays idle for too long, air will condense in the fuel tank and the engine sump, becoming water and thus necessitating frequent service and filter replacements, and the battery might drain

if the vehicle is not equipped with a kill switch.

Hi, Marvelous job you are doing. I have been driving a Nissan Datsun pick-up with a petrol engine for the last 15years. The last two years has been a hell of a time due to distributor problems, resulting

in unending misses and reduced power output, coupled with increased fuel consumption. I replaced the point distributor with a magneto one, which didn’t last long before blowing out. Please help.

Stephen Kurenja

I hate to sound cynical, but get another distributor. Also, if it has got to the point where a problem is recurrent despite constant rectification, perhaps it is time to get rid of the car before it drives you into a depression.

The process for swapping from a single-point distributor to an electronic one is to get the replacement one complete with its mount from a similar but newer engine, e.g an electronic distributor from a newer  engine could go right into an older L20 – hook up the wires and you’re good to go. I think the mistake that led to the “blowing out” was in the wiring part, because it is not that easy for non-electricians.

Due to timing variations, wrong distributor-pedestal combinations are likely, and there is a way in which the spark plugs can be rewired to compensate for this, but like I said, you have to know what you are doing

Comments

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One thought on “If your engine cuts off in motion, most likely cause is vapour lock

  1. Hi I like your advise on Car related issues and now Need your expert opinion
    Im Planning on buying a privately Used Nissan Caravan in a few weeks time here in Kenya preferably the new model and finding that most sellers have changed the engine from the zd30 engine to qd32 engine or td27 engine. All are citing that the zd30 engine is a headache and very problematic.I would like your advise on this.

    Brian

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