fuel injectors and ECM

[guest7791]

Has anyone else had a problem with fuel injectors and ECM? We have our first Jazz from 2013 and sad to say the engine is bust after 5 years: there are 4 injectors: diagnostics said injector 3 was broken but this then broke the ECM which is the expensive computer part. Honda can't tell if any of the other 3 are broken without replacing them ( £250 each) so total bill £1750. If they dont replace them risk is they break the new ECM. Spoken to our garage and they say another car the injector breaking wouldnt have broken the ECM and also other cars you can test if the injectors are broken. I think this is a design fault and been waiting nearly 2 weeks for Honda to get back to me. At least 2 other care in our local area have had the same problem. anyone else come across this?

[Jeff B]

I realise this thread is 2 years old but only in the last week my 2014 Jazz automatic has had a similar problem. Apparently it needs injector 3 replacing. The engine management light came on but the engine was running really rough so we didn't need the light to tell us to stop the car immediately!

The injector is going to cost £390 to replace but I am more concerned now having read this post as this event may have damaged the computer. It was noticeable at the time that the VSA and EPS lights also came on although these obviously have nothing to do with fuel injection so it could indeed mean that the ECM is affected. The local Honda garage seem confident that just a new injector will do the trick, so fingers crossed!

[Jeff B]

Further to my earlier post, would it help to use Redex regularly to prevent injector problems? I have been reluctant to use any additives up to now in case it affected the warranty but that has expired now. I have always used Redex in my Honda petrol engine on my lawn mower and it starts and runs like a dream 13 years on!

I should add that the car is used very infrequently and is quite low mileage: 44,000 in 6 years. Virtually all short trips.

[culzean]

Further to my earlier post, would it help to use Redex regularly to prevent injector problems? I have been reluctant to use any additives up to now in case it affected the warranty but that has expired now. I have always used Redex in my Honda petrol engine on my lawn mower and it starts and runs like a dream 13 years on!

I should add that the car is used very infrequently and is quite low mileage: 44,000 in 6 years. Virtually all short trips.

A bit of redex will certainly do no harm,  think of the injectors as your shower head and petrol as dinosaur juice ( it isn't as clean as it seems ) when the shower head blocks up with limescale most people reach for the de-scaler to clean it up, your injector nozzles and finer than the ones on a shower and when petrol is left on them it evaporates and leaves a film behind ( like the resin of the trees that made crude oil in first place ), this happens more on low mileage cars used for short trips and redex is even more beneficial - petrol itself will not dissolve the gunge left behind in fuel system because it came from petrol in the first place - it is a bit like asking water to dissolve limescale ( it would at  ph less than 7, but water companies don't like acidic water - it corrodes their equipment and pipes, it has even been known to cause pinholes in copper pipes ).

I have used redex for many years,  and have used it to clean carburetors - amazing how quickly it shifts the gunge off an old dirty motorbike carb.

[Jeff B]

Further to my earlier post, would it help to use Redex regularly to prevent injector problems? I have been reluctant to use any additives up to now in case it affected the warranty but that has expired now. I have always used Redex in my Honda petrol engine on my lawn mower and it starts and runs like a dream 13 years on!

I should add that the car is used very infrequently and is quite low mileage: 44,000 in 6 years. Virtually all short trips.

A bit of redex will certainly do no harm,  think of the injectors as your shower head and petrol as dinosaur juice ( it isn't as clean as it seems ) when the shower head blocks up with limescale most people reach for the de-scaler to clean it up, your injector nozzles and finer than the ones on a shower and when petrol is left on them it evaporates and leaves a film behind ( like the resin of the trees that made crude oil in first place ), this happens more on low mileage cars used for short trips and redex is even more beneficial - petrol itself will not dissolve the gunge left behind in fuel system because it came from petrol in the first place - it is a bit like asking water to dissolve limescale ( it would at  ph less than 7, but water companies don't like acidic water - it corrodes their equipment and pipes, it has even been known to cause pinholes in copper pipes ).

I have used redex for many years,  and have used it to clean carburetors - amazing how quickly it shifts the gunge off an old dirty motorbike carb.

Thanks for your response. A case of closing the stable door after the horse has bolted in my case, but I'll definitely be using it from now on!

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?

[Derkie54]

Would super unleaded like V power help occasionally, it's supposed to have more detergents to keep the engine cleaner.

[123Drive!]

Definitely Shell V Power helps. Plus my Jazz seems to go faster with it. But now petrol price has gone up, it's now more expensive.

[sparky Paul]

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.

[Jeff B]

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.

Thank you for your reply. In my case I think there is definitely a fault with the injector rather than some spurious signal to the ECU as the engine sounds really rough and lacks power. What I am concerned about is the other warning lights that appeared at the same time viz the EPS and VSA lights - is this an indication that the ECU has been "damaged" as in like a file corruption in the software of a computer? I suppose we won't know for sure until the injector is replaced and the engine is running.

[olduser1]

+1 for ECUtesting they sorted issue on VW Scirroco sometime back.

[Jeff B]

Bad news. ECU has been damaged because of a short in the fuel injector. New ECU is £980 + VAT! Ecutesting will refurbish for £318 all in, with lifetime warranty. I don't need to think about the decision too long somehow! Thanks for the tip Olduser1.

[culzean]

You think they would put fuses in ECU outputs to things like ignition coils and injectors to protect ECU from short circuits when peripherals go bad...

[sparky Paul]

You think they would put fuses in ECU outputs to things like ignition coils and injectors to protect ECU from short circuits when peripherals go bad...

Indeed, a nice row of externally replaceable miniature fuses would be much more useful than a dead ECU 

The transistor outputs normally incorporate a current limiting resistor to protect the output device to some extent, but if the current is high enough for long enough, these blow to protect the rest of the circuit. It is possible to protect a transistor output from a direct short with a few more components, but components cost money... Some manufacturer's ECUs seem to be far more robust than others, and as said earlier, the mark 2 Jazz ECU is prone to this failure.

[Jeff B]

You think they would put fuses in ECU outputs to things like ignition coils and injectors to protect ECU from short circuits when peripherals go bad...

Indeed, a nice row of externally replaceable miniature fuses would be much more useful than a dead ECU 

The transistor outputs normally incorporate a current limiting resistor to protect the output device to some extent, but if the current is high enough for long enough, these blow to protect the rest of the circuit. It is possible to protect a transistor output from a direct short with a few more components, but components cost money... Some manufacturer's ECUs seem to be far more robust than others, and as said earlier, the mark 2 Jazz ECU is prone to this failure.

The guy at Ecutesting says that they will replace some components with more resilient types so this may address the issues you mention - hopefully! This is my third Jazz - never had any problems with the first two. Would there be any mileage in my writing to Honda to express my disappointment? As the OP said, could this be considered to be a design fault?

[sparky Paul]

The guy at Ecutesting says that they will replace some components with more resilient types so this may address the issues you mention - hopefully! This is my third Jazz - never had any problems with the first two. Would there be any mileage in my writing to Honda to express my disappointment? As the OP said, could this be considered to be a design fault?

I'm guessing they will fit uprated output transistors and perhaps some ancilliary components, but I don't think there will be significant changes to the circuit. Just a guess, mind. Whilst that would help in future, it won't make it indestructible.

You can usually tell when an ECU has a particular weakness when ECU repairing companies offer a service dealing with a specific, documented fault. I think it's clear that the mark 2 Jazz ECU has a weakness, but proving it would be difficult, and I would think getting the manufacturer to admit it, impossible.

However, there is a train of thought that says, "don't ask, don't get"... though any offers of assistance from the manufacturer usually come in the form of goodwill - normally a contribution to the cost of the work at a franchised dealer. Obviously, that doesn't stop you from pointing out that the issue is known one, and expressing your disappointment - you might get lucky with some goodwill vouchers towards future dealer costs... do they still do stuff like that?