Uneven acceleration, Nissan want £1000 to fix!

[silinda]

Hi all, i have mentioned this fault before in that i have an uneven acceleration mostly in 1st and second gear at low revs making for moving away and stop start traffic an utter pain! Local Nissan dealer has diagnosed and i quote " Check and report on hesitation when pulling away and acceleration, carried out self diagnosis ,found o2 sensors not switching. reguires all o2 sensors and oxygen sensors.

 

The quote for this work is well over £1000 as the sensors alone are hideously expensive, surely they dont need to replace ALL the sensors? I did challenge them on this but they say they do, i also said OK if this doesnt fix the problem whats next? They said they stand by the diagnosis as they are the Nissan experts and if that doesnt fix it they will sort it out for me.

 

Anyone else had this problem or am i being taken for a ride here, if i thought for a moment this would fix it i am tempted to pay up but just have a horrible feeling that the problem will still exist,

[coldel]

Sure someone will be along to help soon - plenty of traders on here who can help out with parts where needed. Whatever you do do not go throwing money at the stealers straight away.

[Aashenfox]

There's only one thing anyone can take away from your post for certain. You don't trust these guys. Why have people you don't trust work on the car? Take it for a second opinion somewhere else first. In the meantime, I'm sure someone will be along with some realistic prices on the sensors.

Edited June 13, 2017 by Aashenfox

[ZMANALEX]

Genuine Nissan low mileage sensors are in stock at the moment and good to go same/next day.

 

Just drop me a PM if I can help further with the year and model of your car.

 

Alex.

[coldel]

If it is O2 sensors, surely this is an easy job to replace you just need the diagnostic kit to test? Or am I being too simplistic in my basic mechanical knowledge?!

[Richf]

Where are you located , plenty of specialists will be able to confirm the diagnosis and likely sort it much cheaper , I very much doubt this is to do with the o2 sensors

[Tricky-Ricky]

I would very much doubt its down to the O2 sensors, and you would only need the main sensors not the cat monitor sensors, as these are not used for fuel metering anyway.

 

I would be looking at a throttle relearn as this is the most likly cause for erratic throttle/hesitation, followed by investigating cam/crank position sensors which can be expensive to replace, but i would not trust that particular garage.

[CLASSIX]

I would very much doubt its down to the O2 sensors, and you would only need the main sensors not the cat monitor sensors, as these are not used for fuel metering anyway.

 

I would be looking at a throttle relearn as this is the most likly cause for erratic throttle/hesitation, followed by investigating cam/crank position sensors which can be expensive to replace, but i would not trust that particular garage.

First thing to my mind was a Throttle relearn. & you are quite right not to have total faith in a main dealer, we had one try to rip us off a few years back, it did however cost that main dealer very heavily in the end. :-)

[Stutopia]

Sack the stealer off and get it to a specialist like Horsham or Cougarstore or one of the others. However far away you are from one, it surely can't cost a grand.

[davey_83]

I'd initially opt for a ecu, throttle body, idle control valve and throttle pedal resets in order on warm engine and see how you get on.

[TT350]

I had this problem and it turned out to be a Coil pack.

 

Took it to dealer first who diagnosed it as lambda sensor fault if I remember rightly. Whatever it was, they also wanted £1k.

[-G-]

As soon as you described the issue, I immediately thought coil pack.

[Tricky-Ricky]

Coil pack issues usually show up when the engine has thoroughly warmed up and under load rather than just pulling away etc, as the higher the cylinder pressures the harder it is for the coil/plug to ignite the mixture.

[silinda]

Thanks for all the replies its much appreciated, as for pedal dances etc its all been done many times before as has most other items easily replaced, filters plugs etc, but problem still persists, most unusual that any car can have a hesitation at a very set rev level ie 1000rpm below ok above ok! so negotiating slow moving traffic is a pain! Anyhoo i will update on any info i get which may help others in the same boat! Thanks

[Roscoe]

If your car is a Hr it Will be an exhaust cam control problem that can be sorted with an uprev remap. Also what is your oil pressure on hot idle?

 

 

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[silinda]

Hi, yes its an HR but surely not every HR needs a remap? Oil pressure at idle is around 30 bar and idles at around 500rpm

[Roscoe]

Not all hr's are as bad as others. Sometimes the hesitation at low rpm can be exaggerated if the oil gallery gaskets have failed which is a common problem on all hr's. That would show up as about 15 psi at hot idle.

 

 

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[Roscoe]

If your oil pressure is fine. I would just go for an uprev map. It transforms the drive of the car. Engine will be silky smooth at all revs. Also a lot cheaper than what Nissan are quoting you for something that won't even fix it.

 

 

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[Richf]

Give Jez at Horsham Dev a call , I know he has had a lot of success with various HR ecu niggles

 

http://h-dev.co.uk/2016/08/18/350z-hr-vq35hr-high-idle-fix/?v=79cba1185463

[coldel]

As others have said talk to specialists, Jez is very good

[silinda]

RESOLUTION !!! Hi all and again thanks very much for all the replies and help, after a lot of advice about many things relating to this fault i decided to carry out the exhaust valve timing relearn which seemed to make a small difference but certainly didn't fix the fault, so decided to change the oil to 10/40 oil in which i hoped would raise the oil pressure slightly, my thoughts being that this would somehow help with oil pressure fed variable valve fairies and goblins or however this all works inside these machines, anyhoo the upshot is that the fault has disappeared, i have tried my very best to get the niggle to happen but am now happy it has went away. OK it states in the handbook that 5/30 is preferable but in the absence of 5/30 you may use other grades dependent on outside temperature, and the car may have indeed been ran on thinner viscosity oil before i had it then when i took the car and changed the oil to 5/30 fully synthetic perhaps it was this that upset the apple cart? So now the car is accelerating through the dreaded 1100 rpm point without the niggle?? Hope this bit of info may help others with this HR engine problem.

[ZMANALEX]

Great news, every day is a school day.