Mazda CX-5 SE-LUX 2.2 2WD Diesel. - Engine failure - Gary Bauer

I have a 2013 CX-5 Lux 2WD with approx 55,000 miles on the clock. Driving at around 30mph, the engine cut out without any warning - no spluttering, no failure lights. I just coasted to the side of the road to park at the kerb. The engine hasn't started since. Starter turns well, but just won't fire.

It's been with the dealer for three weeks now. They initially replaced the PCM (main computer) to no avail, and since then they have struggled to identify the cause.

Their latest theory is that it may be the fuel pump, and they are trying to suggest it was caused by me filling it with petrol instead of diesel two years ago, despite havingthe tank drained before the engine was started.

My questions are:

1. Is it really likely that even if the tank was drained, this could have such a devastating effect two years later? If so, is the correct thing to do really to replace the petrol tank after a misfueling?

2. If it is a fault with the fuel pump, would I have not noticed at least some spluttering, and shouldn't a waring light have come on before the engine died?

3. Would such a major failure take over three weeeks to identify and confirm on a modern car with all its diagnostics?

A lot of questions, I know, but I'd appreciate any advice.

Mazda CX-5 SE-LUX 2.2 2WD Diesel. - Engine failure - RobJP

My questions are:

1. Is it really likely that even if the tank was drained, this could have such a devastating effect two years later? If so, is the correct thing to do really to replace the petrol tank after a misfueling?

2. If it is a fault with the fuel pump, would I have not noticed at least some spluttering, and shouldn't a waring light have come on before the engine died?

3. Would such a major failure take over three weeeks to identify and confirm on a modern car with all its diagnostics?

A lot of questions, I know, but I'd appreciate any advice.

1. Yes. Basically, a fuel pump in a diesel engine is lubricated by the diesel itself. Running petrol through it (and that would happen just by it pressuring up on the ignition, not even running the engine) could well have caused lots of accelerated wear, which has taken a long time to show up.

2. Maybe. But when a fuel pump fails, it often just fails. Running one minute, dead the next.

3. Maybe, maybe not. Diagnostics aren't infallible, and it might have been registering faults that were unrelated to the problem.

Mazda CX-5 SE-LUX 2.2 2WD Diesel. - Engine failure - hardway

3 weeks?

They don't have a clue.

And swapping out the PCM doesn't inspire me either.

If it were here I'd start by checking the crank angle signal on the scan tool maybe the 'scope.

Once that is checked as good I'd want to know the rail pressure.

IF that was low then I'd be thinking possible pump/supply fault.

Forget this modern electronics and diagnostics.

It means squat if you don't understand the prinicipals.

I'd be taking it to a diesel specialist if they haven't got a solid diagnostic in a day and that's being easy on them.

Usually I have a pretty good idea of any fault in way less than a day.

Unless it's electrical wiring faults as they can be a b*****.

3 weeks is out of order.

Mazda CX-5 SE-LUX 2.2 2WD Diesel. - Engine failure - liammcl


Can I ask a general question here...

If a car's fault can't be found easily,
do garages, try a few attempts, (3-4 hours say)
and then put it on a backburner to get on with the money jobs
as surely they can't keep charging hourly rates over silly hours for a undiagnosis nor a fix?..or can they?

I know they have overheads etc etc
but when do they call it a day...and when do they inform the customer that the price is going up and up, but no cure in sight.

Just wondering ....
not going into the man hours, skill, diagnostic machines, insurance overheads, wages , tools costs etc

I just wondered what happens if the garage can't find or fix the fault
do they do a few hours, and rinf the customer and say "do you want to continue"

What if they start swapping bits ,and the bits aren't curing the problem?

Just wondering what happens in garages these days

In my work , (computers)
I do a no fix, no fee guarantee....
Some of my competitors, charge for no fixes, when the problem is that they do not have the knowledge to fix things...
This means that the customer is paying a computer technicians, big bucks, just for the technician to learn the skills which they should've had,
or the technician walks away with a paypacket for a no fix.

Cheers
Liam

Edited by liammcl on 06/03/2017 at 20:20

Mazda CX-5 SE-LUX 2.2 2WD Diesel. - Engine failure - gordonbennet

Last car i had that visited a main dealer was Outlander 1, selling dealer put it into Mitsi dealer to suss out hard hot starting, nothing came up on diagnostics and basically they were clueless...edit, no i did put the previous Landcruiser into Toyota for cambelt change, job done.

I got cheesed off, collected the car cos as you say Liam they'd stuck it outside presumably till the wizard of oz did the business with his wand, and slipped it round to my LPG man, who daignosed it as valve seat recession and had the adjustable tappets adjusted up in about an hour.

As above, i'd have this car straight into a Diesel specialist, the very last place it would go would be a main dealer, goodness knows what the current bill is at Clueless Inc.

Edited by gordonbennet on 06/03/2017 at 20:37

Mazda CX-5 SE-LUX 2.2 2WD Diesel. - Engine failure - Peter.N.

I would agree with the advice above, take it to a diesel specialist, they usually know what they are doing, many garages don't.

 

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