My X-Trail has become a constant ulcer-inducer. Around the time of the recent fuel shortage, I had to accelerate hard, and when I slowed down the vehicle went off.
Since then it has been doing it every now and then. On particularly bad days it can go off four times on a 10-kilometre stretch, yet other times it can go for weeks without as much as a whimper.
I have had the car checked and I changed the crankshaft sensor since that was the only error registering on the computer.
I also suspected the cause could be the fuel, so I changed the fuel filter — it had never been changed since I bought the car because my mechanic and some blogs say this does not have to be changed.
I have also noticed that if I refuel during one of those dying spells the car becomes perfect… until the fuel starts inching towards the quarter tank mark. Do you think I need a fuel system cleaner?
Regards,
Gitau
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Hello Mr Gitau,
Yours sounds like a fuel pressure problem. Maybe it is time you looked at the fuel pump if the filters are fine.
You say that, as the fuel gets less in the tank, the problem gets worse. You could be suffering from another fuel pressure problem called “running out of gas”.
I have seen this happen before, in a Toyota Ipsum (the old one), where the car would go off at exactly the quarter tank mark, and nothing less than Sh1,000 worth of fuel would get it moving again.
So another diagnosis would be a faulty fuel gauge. The constant stopping is usually a failsafe that is fitted in most cars: the first time it goes off is a warning that you are running on fumes.
The next few engine cranks will see you actually running on fumes, so coming to a dead stop would be a gamble.
About those blogs and those mechanics, depending on what you feed your car, where you feed it and where you drive, sometimes the fuel filter WILL need to be changed, just like the other filters: the oil one and the air one.
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Dear Baraza,
I drive an old model Subaru Impreza (1998). I have been having two problems with my hitherto well serving machine.
First, I one day woke up to some whistling sound from the engine when I turned it on, coming from around the bearings near the alternator, the fan belts and the bearings.
The whistling disappears after some minutes when I continue moving. Two, the vehicle is auto, and it jerks when I slow down and need to accelerate again.
I recently changed the fuel and ATF filters. Earlier I had changed the CC and ATF oils. The jerking has reduced, but it is still there. What could be causing these issues?
Thanks,
Mwangi.
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Hello Mr Mwangi,
Is the whistling more of a shriek or is it just a whistle? If it sounds like someone is stepping on a cat with a sore throat, then the fan belt is the problem: it could be worn out or out of kilter within the pulleys.
If old, replace. If out of place, push it back into place. One bush remedy I learnt from a motoring mentor is that a cure for the symptom is to splash some brake fluid on the fan belt, irrespective of the cause.
This is a temporary respite from the noise; you will still have to solve the problem. Then again, maybe the bearings have reached the end of their usefulness and are just expressing their need for change or replacement.
To confirm whether it is the fan belt is simple: while stationary, with the engine on, turn the steering wheel all the way to the end (either left or right, you decide).
At full lock (the very end), the shrieking should start again, and stop the moment you let go of the wheel. About the jerking transmission, I was going to suggest you check the ATF, but you beat me to it.
Now, which ATF are you using? One local brand (I dare not mention it) is notorious for its uselessness and unreliability, and is only used in power steering systems.
And I thought automatics only use ATF*, while manuals use CC*, so why did you put CC in your auto? (* this is pending confirmation).
The last suspicion would be that maybe it is time you got a new gearbox; your current one also having reached the end of its usefulness, in which case you have my sympathy because the repair bill that is coming your way will be horrendous. Let us hope this is not the case.
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Hello Baraza,
I have a 1997 Mitsubishi Galant VRG. When cornering hard left, I feel a pulsating tug to the right through the steering wheel, at the rhythm of a ticking clock.
There is no cracking noise to suggest any problems with the CV joints, but could this be a problem with the same?
And while you’re at it, Sir, please tell me at what rpm my engine should idle. I suffered low idling (as low as about 400rpm) and occasional stalling recently.’
Had a mechanic adjust it to 1,000rpm, but now it has an annoying vibration that only goes away when I engage ‘Drive’, bringing the rpms to about 700.
Regards,
Kuria.
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Hello Mr Kuria,
How bad is the pulsating? If mild, it could be what we road test people call “steering feel”, the pulsating could be the shock wave coming from the tyres as they scrabble for grip at the limit, as well as the self-centering I talked about last week (the harder you push, the more nature — and physics — fight back).
Then again maybe the bushes in your steering arms/tie-rods/knuckles are aging, so they do not do as much damping as they should, hence the feeling.
Four hundred rpm is ridiculously low for a petrol engine to idle, even though the larger displacement units idle at lower revs than smaller plants.
Your car should idle at about 850 rpm, so even the 1,000 you set is higher than normal. The prime suspect in the vibration at idle is a dying spark plug, or one problem commonly experienced but not commonly diagnosed correctly — and thus not commonly cured.
You might have a problem with a vacuum leak. Check the intake plenum, the PCV valve (Positive Crankshaft Ventilation), hose and elbow.
Also check the connection between the air cleaner and the throttle body. If a crack or a hole appears anywhere on these sections, then you have your culprit.
Silicon should shut these escape routes convincingly. IAC (Idle Air Control) is supposed to send more air through the engine to compensate for an additional load such as A/C or alternator.
Clean the terminals to it and take it off and spray some WD40 into the two chambers. It is located on top of the throttle body.
To check for a vacuum leak, put a vacuum gauge on any intake port and it should read 18 to 20 inches at idle.
If it has less than that you have a leak or the catalytic converter is plugged or the muffler is plugged. If you have normal power at speed this can be ruled out.
Another cause could be loss of compression in one of the cylinders. A simple compression test would confirm this, and from there your mechanics will tell you what is next: maybe a leaking gasket, worn piston rings or little oil (very unlikely).
The lack of equality in compression pressures across the cylinders causes vibrations.
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Hi,
I recently changed my tyre rim and size and now notice that, to achieve a 100kph on the speedometer, the car takes the acceleration needed to achieve 120kph on earlier tyres.
The vehicle seems slower now, yet I only changed from size 14 to 15. What is the effect of bigger rims/tyres?
Anthony.
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Hello Anthony,
I had discussed this before. Bigger tyres have the effect of gearing up a vehicle (takes more torque to turn the bigger tyres than it does smaller ones.
That is how gearboxes work). So, in effect, the gears in your powertrain are virtually “taller” courtesy of the bigger tyres.
Bigger rims on same-size tyres have no effect on torque delivery to the tyres: the low profiles look good and improve handling, but send the comfort levels to the dogs.
However, the difference between 14- and 15-inch tyres should be negligible. Consider looking at the tyre type and pressures you are using.
Lower pressures increases rolling resistance, causing you to overwork the engine, while low friction eco-tyres offer little push-back to reduce the need for hard acceleration.
