fuel injectors and ECM

[Jeff B]

The notion that because the ECU has electricity flowing through it during normal functioning somehow causes wear and tear is surely laughable isn't it!? Especially after just 44K miles!

I suspect your ECU problem was nothing to do with 'wear & tear' as such, but the ECU being unprotected internally against an external short circuit caused by the dead injector. What they are really saying is "it's nearly 10 years old, you've had your money's worth."

Stand by for a bit of waffle, but there is a serious point to it at the end.

There are a few problems that particularly afflict modern electronics as they age. Certain components deteriorate with age, and loads of cheap electronics have been manufactured using poor quality capacitors - up until very recently, there was an epidemic of cheap TVs failing after 18-36 months due to junk power supply capacitors. On this score, things have improved a bit.

The other thing that has caused problems is the introduction of lead free solder. It's prone to dry joints where heat cycling is involved, and in older equipment, weirdly grows conductive crystalline threads, causing short circuits. The fix in both cases is to remove it and re-solder with good old fashioned leaded solder.

That's progress for you.

Now comes the punchline. In ten years time, when people like us are looking at buying secondhand hybrid and electric cars, the electronics in these will be approaching the point when the problems start piling up. Even before you consider the batteries, the electronics are so complex, repairs will soon become uneconomic.

The car was actually only 6 years old and we had owned it for only the last 4 of those. I assumed we would have it for a least 10 years as we only do about 6000 miles p.a.  Is it worth pursuing this matter with the motor ombudsman do you think?

Agree 100% with what you say about hybrids/electric cars, especially the hybrid as, being a pessimist, surely there is a lot more to go wrong with these as you have the worst of both worlds - the complexity of the petrol engine combined with the electronic complexity of having the two systems trying to work in harmony.

The Mk3 has a lot more bells and whistles than the Mk2 but a lot of them I wouldn't miss if they went wrong like the automatic headlights and automatic windscreen wipers - that's assuming of course that they don't wreck the ECU if/when they do fail!

Funnily enough we were planning to have only one car from October on (car insurance renewal time) but after what has happened I am rather loathe to part with my trusty 2007 manual version Mk1 Jazz. It is not worth much in monetary terms but as a reliable back up and general workhorse somewhat more valuable!

[Riobinman]

Any thoughts on the ECU issue? It sounds a bit worrying although the Honda garage seems confident that the only issue is that of the faulty injector. I'm pretty sure if there was a way of getting extra cash from me then they would be delighted to do so! I'm thinking that this may be a rare problem and even when they have fixed the injector the other warning lights like EPS and VSA will reappear. I presume when they carry out the diagnostic test that the ECU would report if there was a fault within itself as well as other faults?

ECU damage from faulty injectors is not common, but not unheard of either. If anyone is faced with an expensive ECU replacement, I would recommend considering one of the specialist companies that repair ECUs, such as BBA-Reman or ECUtesting.

Random fault indications are often related to low system voltage - usually a low or failing battery, but can be triggered by a faulty component, such as a shorted sensor or injector.

A diagnostic test may not specifically report a fault that is within the ECU, but where this fault relates to the external interface, you would see error codes related to the running fault that the problem is causing - in the case of a dead injector, you should get an indication of a constant misfire.

IIRC failure of injector outputs is a known fault on the ECU of the mark 2. Really, the suspect injector needs to be tested, rather than the usual "change this and see if it fixes it" approach.

Further to this thread, I had a new 1.4 EX in 2012 and subsequently sold it within our family last year and last week this same issue arose.
I didn't get involved initially as I'm not local to the family member, but at the garage one injector was measured at 2.5 Ohm DC resistance where the other 3 were 11 Ohm.
Replacing the injector didn't fix it, so the ECM was sent to someone, who diagnosed a chip had blown. The chip was marked up as SSD 103 and a search on the web yielded just a datasheet and no stockist, could well be out of production. The chip manufacturer was ETC. The SSD 103 is a surface mount power transistor using lead-free solder on the PCB. the mechanical size of the chip is ~5mmx5mm. It is rated at 10amp max, which may tolerate the ~7 amps pulsing into the faulty injector, rather than the ~1.5 amps pulsing into the 3 good injectors. The duty cycle of injectors is higher when the engine is cold or at high speed/load, something around 60% per engine rev for each cylinder at full load.
There is no explanation for the injector failure which occurred within 5 minutes of starting the engine, other than the coil within the injector shorting turns out, reducing the resistance, increasing the current and exceeding the transistor rating, whilst not opening to deliver fuel. No amount of fuel treatment would have prevented this type of fault occurring.
Getting any progress at this time of year will be a struggle, but I've suggested sending the ECM it to one of the repair specialists mentioned in this thread.

[sparky Paul]

There is no explanation for the injector failure which occurred within 5 minutes of starting the engine, other than the coil within the injector shorting turns out, reducing the resistance, increasing the current and exceeding the transistor rating, whilst not opening to deliver fuel. No amount of fuel treatment would have prevented this type of fault occurring.

Yes, shorted coil windings is just one of those things - a faulty solenoid caused by poor insulation, encapsulation or some other manufacturing defect. That said, it's a poor circuit design that doesn't limit the current sufficiently on a shorted output.

As for the transistor, I can actually source these. They may indeed be obsolete, but a couple of overseas trade suppliers are still showing stock. Many of these more obscure components are simply not available here, some having only single manufacturing runs, but there is very likely a more easily available substitute.

Thanks for the useful info, well worth posting. I might add a strip of those next time I put an order in... we have a mk2, and you never know! 

[Jeff B]

Just a quick update after 3 years to say that our Mk3 Jazz has given no problems. Hope that's not a case of "famous last words"!