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Mechanical issues remind us cars are fiendishly complex machines

Wednesday December 11 2019

car engine block

Last week, l visited my mechanic for service and there were some engine oil spills on the engine block. PHOTO | COURTESY  

BARAZA JM
By BARAZA JM
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Dear Baraza,

I truly and humbly appreciate your response to my cry for help. I would like to share some good news about one of the articles you responded to on October 9, 2019.

As you were contemplating your response, I was also doing a lot of research and brainstorming sessions with other car enthusiasts. I eventually got an honourable mechanic who worked closely with me to resolve the issues my car had.

I replaced the cylinder heads, which were measured and confirmed to be standard. I had the engine block tested again and we found that due to excess misfires, the block was overheating and thus had bent slightly. This was schemed and restored.

We assembled the engine but the misfires didn’t go away and so dissembled the engine several times until we sat down with the mechanic and realised our compression ratios were completely off.

We decided to recheck the block and, after a sixth disassembly, we found the two bank piston rings were stuck. The beauty of this engine is that it has sleeves or/liners since it’s an aluminium cast block and so we took the block to the machine shop to be re-bored and re-sleeved afresh for all cylinders. The block came back and we assembled the car but the misfires persisted. After some further brainstorming and calling a wiring guy, we removed the pre cat O2 sensor and drove the car without it and all firing came back to normal.

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We checked the cat converters and found the previous mechanic had drilled holes but left them half way and upon further checking, all the four cat converters had been completely blocked and thus were choking the engine due to excess back pressure. This is what had been creating the misfires all along.

We gutted all the cats and changed the Bank 2 Sensor 1 precat but we had some micro misfires. The car’s power and push jumped two-fold and the engine was restored with all timing counterchecked and combustion at optimum. I picked the car last Saturday, after spending two weeks at the garage.

I have driven the car now since last week and so far the only problem is the post cat O2 sensor projecting an engine light on my dashboard due to the gutting of the cat converters.

After further research, I stumbled on information about how Europeans cheat on emission tests, (we don’t have emissions tests in Kenya so I can use this option) by using a spark plug non-fouler which are used to extend the O2 sensor element such that the amount of flow in the exhaust is limited, thereby removing the engine light and also controlling feedback to the ECU on oxygen levels in the fuel which in turn sends a signal to the precat and ECU and injectors on fuel management.

I have ordered the parts from Amazon and I will share an update once it’s installed but, all in all, your response in the paper has helped me get a new front as I work towards another one.

The lesson picked is that my cat converters were the main problem from day one and if I had gutted them beforehand I wouldn’t have reached these lengths. I have also learnt that I can sleeve a cast iron engine block which is my next project for my Pajero IO Farina Pinin 1999 Model (I love this car).

I learnt more about my engine in two weeks than I have in 10 years.

Thanks in advance,

Morris K.

Hi Morris,

What a read! It all points out to the response I gave on October 9: that cars are fiendishly complex machines and sometimes the root of a problem is something that is not immediately apparent despite the obviousness of the symptoms. Who would have thought that the catalytic converters were the culprit since they had blocked holes in them?

I am glad the car is running again, even after two weeks of trial and tribulation, and I am glad this column was instrumental towards that end. That emissions cheat of yours is a new one to me (live and learn); the path I would have taken is simply access the ECU and delete that entry in the programming.

It is the same way a DPF-delete operation works: remove the DPF then hack the ECU to tell the car that it doesn’t have a DPF, so could it please stop throwing a check engine light? Let us know how the parts from Jeff Bezos’ pantry treat you.

It is possible to re-sleeve an engine, which is usually a critical component in the engine overhauling process; but before you embark on this, first find out if it is possible on a particular engine that you want to work on. For some, all it takes is to replace the sleeves; in others you may need to do reboring, which is carving away at the engine block itself along the cylinder walls. This one is usually a lot more delicate and involving, so not many people opt for it.

Welcome to the dark side of motor vehicle ownership. Many people can share your experience: there will be one major breakdown or mechanical issue that will teach you infinitely more about an engine or how cars work than you have learnt over the rest of your life. Many of us can identify with that.

My alternator drive belts don’t last

Dear Baraza,

I have owned a 2005 ex-UK Pajero Shogun for the past three years. All was well until I replaced the alternator drive belts. They hardly go for more than three months. The car has stalled on three occasions because of the same. I buy them at Simba Colt Motors.

Kindly tell me what the problem could be and a possible remedy. Thanks.

Regards, Irungu

Hello Irungu,

It seems that as much as I try to avoid them, certain brand names and franchise labels will just not go away, then I’m told in very harsh language that I have something against them. Well, they should see the emails I ignored before choosing to answer this one. The picture is very grim.

So, you have a belt-eating Mitsubishi. Despite what I said in response to that lengthy message from Morris, your problem seems a bit straightforward: whoever is replacing those belts is not fitting them properly. He needs to exercise more precision when dressing the belt over the pulleys; right now it’s the belts that are getting destroyed, but in future a pulley could seize as a result, with more disastrous results.

Of course it is entirely possible that so-and-so is selling you substandard belts, which is why they go after only a short time, but surely, they wouldn’t do that... would they?

This is Kenya, after all. Try a new source of parts, as well as a new mechanic, and see if things will improve.

What’s your take on the BMW X5?

Hi JM,

Your vast knowledge on matters motoring has been a big help to people like us, thank you. Having said that, I am a big fan of the BMW and currently have a 320i E46M54 engine.

I am thinking of an X5 but I was advised that the E53 is the best model for X5 ever made. However, I seek your indulgence and advice as regards the X5.

Regards, Mtei

Hi Mtei,

Those who say the E53 is the best X5 ever made have most likely never driven anything else except an E53. Sure, the E53 is a good vehicle in and of itself, but come on, it’s what now? 20 years old?

The E70 that followed was objectively better than its predecessor in all measurable ways (and immeasurable ones, like the looks department), the F15 received rave reviews on these very pages (DN2, March 29, 2017) and finally the current G05 came dangerously close to winning the Motoring Press Agency Car of the Year Award, only losing out because it costs as much as a Range Rover Sport, which is a car for 1%ers and is out of reach for the majority of us. To put it comparatively, the cost of one G05 X5 could get you two Toyota Fortuners (the eventual winner of the award in 2018).

That being said, it seems you are shopping for a used X5, in which case get an E70. The E53 is outdated and getting a clean one is going to be difficult. The F15 is still relatively new despite being replaced by the G05, so it is likely to be pricey even on the used front.

The G05 has four turbos in certain forms, a trait it shares with a Bugatti Veyron/Chiron: names that are associated with unrealistic amounts of money, so unless you have a purse stretching towards 8 figures, that car is out of reach as well. The E70 thus wins by elimination.

I like the E70 on its own merit, not just by eliminating other cars from the list of nominees. The looks are proper German: staid, reservedly handsome and with thoughtful proportioning of parts and panels. Get it in the right colour and with the correct rims and it is not a bad sight, at all.

Mechanic who wants car’s muffler removed needs to be slapped twice

Dear Baraza,

Thank you for your impressive matters concerning motor cars. I’m a lady owner of a Toyota Rush 2008. Last week, l visited my mechanic for service and there were some engine oil spills on the engine block.

He told me that the muffler should be removed from the exhaust pipe so that the car gets breathing space. Please advise me before I go on to remove the muffler, and what are the side effects of removing it?

Regards,

Grace

Hi Grace,

Please slap that mechanic for me the next time you meet him. Then slap him again, for yourself. When that car left the factory it already had “breathing” space in the form of ports, valves and manifolds; I don’t know what other breathing space he is on about — in fact, that same muffler he is asking to remove is part of the vehicle’s breathing apparatus.

Removal of the muffler will just lead to a noisy car; and not in a pleasant way like some tuned aftermarket exhaust systems. Worst case scenario: your car will lose a bit of power and there is the possibility of burnt exhaust valves, so it looks like this guy is trying to guarantee himself future business by feeding you silly-sounding balderdash. He might as well ask you to get a rhinoplasty done so YOU can breathe better.

Ask him to clean up his oil spill and leave the muffler intact, or else... open palms await.

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