Mazda 6 - SCBS warning, turbo lag

devildolly5

Hi

I was wondering if anyone could shed some light on whats up with my car. First off, I intend to get it to a garage in January, but just cant do it this side of christmas as money is a bit tight.

Its a Mazda 6, 2.2 turbo diesel, 2013. A few months into owning the car (and when the car was 2 years old) the turbo completely went. Replaced under warranty and has been fine until recently.

A few weeks ago I noticed the acceleration has been very slow, and what I assume being the turbo not kicking in until very late, much later than usual for the car since I have had it (think joining a motorway at 40-50 on a shortish sliproad because I just cant get fast enough quickly enough anymore, whereas before I could get there super quick if I wanted to).

Then a couple of days later, every time the car gets to the point when the turbo? kicks in and the car accelerates quickly, an SCBS (smart city braking system) warning light comes on, and sometime with it an engine warning light. It doesnt matter what gear I do this in. I have tried 1-6 and it does it in each gear at the same point.

This doesn't happen if I don't take the car over 2500 revs and keep it below the point where the acceleration kicks in (if you see what I mean). I hope I am explaining this OK.

There is no smoke from the engine, it drives OK apart from being sluggish to accelerate. I have cleaned the windows in case the censors were causing the problem but this didn't help.

I did have the tyres replaced a couple of months ago. Could this be linked?

I appreciate its hard to know without seeing the car, but my question is do you think its likely to be an engine problem, or a censor/engine management problem? Any quick things I can do to check whats up before I get it booked in.

Should I still be driving it?

Cheers

Warwick_Hunt

Will money be even tighter in January if you continue to drive it and it goes bang?

facade

I'd get it looked at, but sounds like the exhaust or the intercooler is blocked to me, which could be a DPF problem if it has one, or one of those strange catalysts that some diesels had.
If there are no warning lights on, I'd assume it was safe to drive for a short while as long as you keep them off, but I wouldn't be driving from Land's End to John O' Groats, keep it to a minimum, as you could be doing more harm.

Obviously, check the oil & fluid levels and a look at the air cleaner and pipework for broken/displaced/flattened pipes is about all you can do really.

IamNotAllowedToUseMyName

Could be all sorts of things, but generally sounds like engine management is baffled by what it is trying to deal with. That normally means some damage somewhere is taking something out of bounds, beyond what the engine management can deal with.

Don't know Mazda's that well, but they are less mainstream than some and may do things a little differently.

So, it could be a sensor fault, a wiring fault, low battery (I've had weird stuff happen with an out of sorts battery), pipework leaking on air intake or exhaust, pipework blocked on intakes or exhausts, or possibly something nasty with the turbo like bearings failing.

Get the idea?

If engine management has come on then there will be a code stored. At least get the code read.

You might think that the worst that can happen is a breakdown, but breakdowns on the motorway can be dangerous, so planning to drive with a potentially breakdown-prone car is unwise, and as others have implied, there could be something on the way out that might take a lot more with it.

cajef

devildolly5 wrote: »

Should I still be driving it?
Cheers

That is your choice if you want to risk a breakdown or possibly causing more expensive damage to the car.

wgl2014

At the very least I would get it booked in for a diagnostic session at a garage. Even if you can't afford the repair you should be able to find out what's wrong and the cost/ risk of continuing to drive.

daveyjp

The Mazda 2.2 diesel is well known for some serious issues which can lead to very expensive problems, including new engines.

Diesel can contaminate the engine oil during DPF regeneration, leading to dilution and this may well be why the turbo failed. Check the engine oil on a weekly basis and if the level is rising it does need to be changed.

Your car needs a diagnosis asap. It is not wise to drive a car you know isn't performing correctly for any length of time, especially a complicated modern diesel.

devildolly5

Thanks all.

I'll get it checked in before christmas if I can.

I don't have any choice about driving it just a few more days for work/nursery as there are no public transport options (work in the sticks). Its a risk I'll have to take, but I'm doing so knowingly. I don't drive it on the motorway anymore (not since this problem appeared).

Thanks again. I'll let you know what the problem was

System

Buy a cheap OBD2 reader you can connect to your laptop or Android phone, one that says it will work with a Ford which will have a switch on the top. This is the Bluetooth one I got from Amazon:

https://www.amazon.co.uk/gp/product/B06XPLSQRS/ref=oh_aui_detailpage_o06_s00?ie=UTF8&psc=1

Download Forscan or install it on your phone from the Google Play Store. It is free for PCs, £3 I think for phones/tablets. It is an in depth tool for Fords and Mazdas and it'll read more than just the OBDII fault codes.

Read everything, post what it finds.

The other thing it'll do is live logging so you can set a sensor, say turbo boost, and log what it does and it'll save that data. That'll give you an idea if the turbo is trying to spin up or not.

It has another trick up its sleeve that might help and that is that it can monitor the DPF internal pressure. The car has two sensors which measure air pressure inside the DPF at its feed and the outlet. Now if either of them show zero it doesn't necessarily mean a blocked DPF as the Mondeo and therefore assuming the Mazda, has a design fault where the two rubber pipes going from the DPF to these sensors harden over time and split. On my Mondeo that threw up a warning light. My garage just charged me 30 minutes labour to change the pipes and provided the pipe for free as its nothing more than 50cm of braided rubber hose.

weejangus

As others have said, this particular engine does have some (potentially expensive) niggles.

1 - Your issue could be a number of things like a blockage in the DPF / exhaust. It could also be caused by a clogged fuel filter. When was it last replaced? If the filter is dirty, it can restrict the flow of fuel. When the turbo kicks in, the demand for fuel is significantly increased so a partially blocked filter will give symptoms similar to a failing / failed turbo. Car will struggle to accelerate.
2 - This is less likely to be your issue but do keep it in mind. The injector seals in this engine are prone to failure at about the 40k - 50k mark. When that happens, fuel can make its way into the engine oil which results in a build up of carbon. Over time, this carbon builds up on the oil pump which will then fail and engine will be starved of oil which will take out the engine AND turbo. Mazda quote approx £5000 to replace the short engine block and turbo (speaking from experience!). Keep an eye on your oil level. If you ever notice the oil light coming on - even just for a second or two - switch the car off and have it recovered.

Hope you get to the bottom of your issue. Highly recommend having it looked at as soon as possible.

J

Londoner_1

A blocked dpf would show a different engine warning sound, best is get the codes read from a good garage.

As someone said mazda 6 diesels are not the best on the market, just google the problems with older mazdas right upto the latest 2.2 model.

Thats why i drive a mazda 6 2.0 petrol which are very good.