Found the fault but need help from a dieselhead

[Kentish]

You may have read a thread or two about a long standing issue we have had with a Nissan we bought brand new and has made a terrible noise (since new) but the main dealer has been too inept to trace and rectify.

This has gone on for nearly 2 years and the dealer honestly can't be bothered.

Anyway, I have found where the fault is associated with but need help with the cause please.

The noise is a horrible oscillating whine, sometimes a steady whine sometime no whine at all. It is so loud at times that the stereo has to be very loud to drown it out. The main dealer said this is normal and "they all do that sir".

They concluded that it is the turbo vacuum pump which is shown in the area of the photo below marked 'A'

What a load of cack!

With the noise evident, I pulled both vacuum lines off this pump and it made no difference and furthermore the sound did not appear to be coming from there anyway.

With the noise still present and very loud, oscilatiing up and down, I decided to pump the rubber priming 'bulb' on the opposite side of the engine bay, in the area marked 'B'.



Hey presto!

The noise immediately stopped.



I does return again after a few minutes but the more pressure you pump with the priming 'bulb' the longer it takes for the noise to return.

Now, my question is, what could be the cause?

I'm suspecting something like a faulty diesel pump diaphram or seal or perhaps a non-retun valve or something like that?

I am not that clued up on diesels (as you can tell)

I'd be eternally grateful if anyone with more knowledge can shed some light on the purpose of the priming bulb and the possible cause of the noise please.

At long last and with no thanks to the main dealer, I appear to be getting closer to resolving this terrible noise!

You'd think that an issue like this would be easy to have sorted on a brand new car but fault diagnosis appears to not be something the techies at Nissan are capable of and their attitude was "you'll just have to put up with it".

They were a lot more customer focussed prior to us parting with the £18.5k for the car!

Anyway, all help is really appreciated - thanks

Edited by Kentish on Tuesday 11th May 13:51

Edited by Kentish on Tuesday 11th May 13:55

[TheRoadWarrior]

need help from a dieselhead




:-D

[Kentish]

TheRoadWarrior said:

need help from a dieselhead




:-D

Is there a site such as?

Dieselheads ....smoke matters

Edited by Kentish on Tuesday 11th May 14:06

[Simbu]

Sorry i can't help you with the problem, but i hope you've been raising hell with the dealership - i'd be threatening to go to Nissan UK since they're not resolving the problem to your satisfaction. Just keep escalating the problem (trading standards etc) until they pay enough attention!

[Kentish]

Yes, completely agree and I have been in touch with Nissan CS UK.

They came back with a page of questions which they could easily answer themselves if they pulled our file out but I guess they all like to make the customer jump through hoops as many will just give up.

[Bill]

I am by no means a dieselhead but on a Landy you need to prime the fuel pump manually if you've run it dry, it looks like that bulb serves a similar purpose. Could it be air in the system that gets compressed when you pump??

[Kentish]

Bill said:

I am by no means a dieselhead but on a Landy you need to prime the fuel pump manually if you've run it dry, it looks like that bulb serves a similar purpose. Could it be air in the system that gets compressed when you pump??

OK thanks, could be??

Would there not be some sort of bleed valve for this - like a hydrostatic relief valve to automatically vent the system?

To have to do this manually would appear to be quite primitive on a 2008 car with a modern DCi engine, to have to manually bleed the fuel system periodically and I'd be quite disappointed (but not too surprised) that the Nissan techs do not know about this.

Maybe an air leak, again - why on earth are the Nissan guys clueless?

Why was I able to pinpoint where the fault is when they had the car 4 days to find the fault and other occasions too but have failed to do so for nearly 2 years?

Quite disappointing that the main dealer has a workshop full of highly skilled and qualified specialists and equipment but don't know what to look for but I'm able to pinpoint where the fault is with just my ears and eyes and a bit of poking and proding.

[Bill]

Kentish said:

Would there not be some sort of bleed valve for this - like a hydrostatic relief valve to automatically vent the system?

- Not if air isn't expected.

To have to do this manually would appear to be quite primitive on a 2008 car with a modern DCi engine, to have to manually bleed the fuel system periodically and I'd be quite disappointed (but not too surprised) that the Nissan techs do not know about this.

- I wouldn't have thought it'd would need it routinely, only to prime the pump if it's been run dry. Diesel pumps rely on the fuel for lubrication.

Maybe an air leak, again - why on earth are the Nissan guys clueless?

Why was I able to pinpoint where the fault is when they had the car 4 days to find the fault and other occasions too but have failed to do so for nearly 2 years?

Quite disappointing that the main dealer has a workshop full of highly skilled and qualified specialists and equipment but don't know what to look for but I'm able to pinpoint where the fault is with just my ears and eyes and a bit of poking and proding.

- Because all they know how to do is plug a laptop/diagnostics in?

If the fuel system is a closed loop with no air entering or leaving it might be that pumping the bulb compresses it so there's less cavitation, or possibly you pump it through.

Dunno really, I'm guessing

I'd try to find a decent independent as they're more likely to be able to think outside the box rather than just being used to simple servicing.

[Kentish]

I know what you mean about an independent but I don't feel that we should have to pay for it when the car was brand new when the fault became evident (2 days old) and is still under warranty for 14 months.

Makes you wonder what a warranty is for!

Thanks for your help and suggestions

[Bill]

I agree, but given the PITA element and that Nissan aren't sorting it that's the way I'd be going.

[skyslimit]

Those priming bulbs have a one way valve in them, which do, after time, start to leak back and allow fuel, if the car has been standing for a while/overnight, back to the tank. Car be be a bh to start then.

Old fords are notorious for it.

Good news is they cost virtually nothing. I'd try that first.

[Kentish]

Yes, I might bang out a letter to them 1st to say that I am going elsewhere on such a date and that if I don't hear back that I will get the work done at the diesel specialist and forward Nissan the invoice for payment.

Perhaps they will then take it in and seek the advice of the specilais themselves.

Fortunately, we have an excellent diesel specialist nearby.

Think I'll give Nissan the opportunity to sort it again first now that I am able to point them in the direction of where the fault is.

[gshughes]

Try another Nissan garage?

[busta]

Sounds like a problem with not enough fuel getting to the pump. Whats the performance like when it's being noisy?

Is there another pump delivering fuel from the tank to the injection pump? If so, it sounds like the pressure switch for this is set too low and it's not pumping enough fuel to keep up with the injection pump.

Have they tried simple things like re-loading the software on the ECU?

[Kentish]

busta said:

Sounds like a problem with not enough fuel getting to the pump. Whats the performance like when it's being noisy?

Is there another pump delivering fuel from the tank to the injection pump? If so, it sounds like the pressure switch for this is set too low and it's not pumping enough fuel to keep up with the injection pump.

Have they tried simple things like re-loading the software on the ECU?

It's perhaps a bit lacking in throttle response.

It has always had a big dead spot where it hesitates at motorway speeds if you lift off then back on again (to overtake for example).

I did tell the local main dealer when it went in for its 1st & 2nd services and they commented that "it is a characteristic of the car, they all do that Sir".

I'm thinking that perhaps the 2 issues are related and that was just more main dealer B/S.

They haven't physically done anything to address the issue so far, just said it is how it is supposed to be and that the noise it makes is normal. Funny that none of the 3 demonstrators we tried were like it!

We seriously would not have spent £18.5k (even £2k) on a car sounding like ours does on a daily basis as it sounds like an old nail!

I'll make sure the points you mention are looked into. Thnaks very much for your help

[P9]

busta said:

Is there another pump delivering fuel from the tank to the injection pump? If so, it sounds like the pressure switch for this is set too low and it's not pumping enough fuel to keep up with the injection pump.

I think this is the issue (was the issue)

I took the car into a different Nissan dealer today who were really helpful and above all, interested in sorting the problem.

I pointed out where the problem is and that pumping the priming bulb stops it and suggested that perhaps it could be an NRV in the filter head.

Sure enough that is what it was!

The cause though was as you said. They told me they had increased the fuel pressure too whilst testing and that had stopped the issue reoccurring and they also fitted a new filter head assembly in case that one had a fault.

Job done!

They also adjusted the tailgate to sort out the rattle and they inverstigated my complaint about a knotchy and noisy gear selector. I'm sure the original dealer would not have bothered and just told me it is "normal" but not this dealer, no - they inverstigated the noise and sloppy feel and reported back that it needs new selector cables.

Great that they checked it and are going to replace them but also a bit disappointing that a car less then 2 years old with 20k miles on the clock needs new gear selector cables!

Anyway....

Very impressed with Dumpton Park Nissan though, great service - very pleased with them and the car will go there from now on.

I did escalate a complaint to Nissan UK and will be very pleased to let them know that the new dealer has done an excellent job.

[Dog Star]

Kentish said:

You may have read a thread or two about a long standing issue we have had with a Nissan we bought brand new and has made a terrible noise (since new) but the main dealer has been too inept to trace and rectify.

Unreal! A mate of mine bought a Z4 3.0 coupe brand new. Whining diff - it was hardly audible IMO. BM chaned diff, gearbox, tried everything. In the end a year later they gave him a new Z4 - by which time the spec had gone up.

Guess what: yep! Whining diff. More moaning and in the end he's ended up with ANOTHER new Beemer - a 335 coupe thing. So he's basically managed 3 years (with a better car each time) of zero deprecitation motoring.

And you've endured two years of this?

[skyslimit]

So I was right about it being a one way valve and leaking back then?

Yeah, your welcome.

[busta]

Glad you got it sorted and gald I could be of assistance!

[busta]

skyslimit said:

So I was right about it being a one way valve and leaking back then?

Yeah, your welcome.

Don't think the valve was necessarily at fault- as you said before the symptoms for this are poor starting which Kentish didn't mention as a problem. It seems they changed it as a precaution though, as like you say, loads of diesels suffer from this.