2014 nissan qashqai jerking in cruise control

alan8373 · 11-12-2023 8:25pm #1

HELP PLEASE just got a 2014 qashqai 1.5 dci when driving in cruise control its jerking a lot and if set at 110 the speedo is saying 118 . I know going down hill sometimes the car might be going faster and sometimes it will feel like a jerking. But this is happening even going on flat or up hill.

I've used cruise control for year's on my old renault.. no problem

mikeecho · 12-12-2023 4:30am

Manual or Automatic?

alan8373 · 12-12-2023 7:51am

Manual .

alan8373 · 12-12-2023 7:52am

Manual .

alan8373 · 13-12-2023 8:12am

Now I've noticed when driving on motorway can be driving fine at 110 and car seems fine but going up even sligh hill and put the foot down to overtake something no power... but on the down hill have power but still not great power .. 😕

13-12-2023 9:42am

https://www.boards.ie/discussion/comment/121489613#Comment_121489613

Do you find a general loss in power, or is it only at speed?

BlakeS94 · 13-12-2023 10:28am

https://www.boards.ie/discussion/comment/121489613#Comment_121489613

Typically if the power is going flat when you you try to floor it, it's a fuel delivery issue. Try changing the fuel filter If it hasn't been done in a while.

alan8373 · 13-12-2023 1:26pm

Thanks for replying. Just serviced and new filter in it .

alan8373 · 13-12-2023 1:28pm

Car seem fine but yes general lose of power now . Car will drive OK but if put foot down no real power. I would not try overtaking anything..

pooley124 · 13-12-2023 2:25pm

Is the clutch slipping? Do the revs increase when you put your foot down but the car doesn't go any faster?

alan8373 · 13-12-2023 2:31pm

No clutch is fine. Not at the car at the moment revs didn't seem to be going up much when it happened. From memory. Could be be DPF ?

kirving · 13-12-2023 5:39pm

Is it only happening when cruise control is set?

Your speedometer is also reading 118 when you have cruise control set to 110.

I'd be looking at a wheel speed, or transmission speed sensor. If either are faulty, the cruise control may not read correctly, but importantly, the difference between engine speed and wheel speed is used to measure wheel spin. If the car thinks the wheels are slipping, it it will cut power to the engine, causing a jerking feeling.

alan8373 · 13-12-2023 5:45pm

Thank you I'll get that checked.

mk7r · 13-12-2023 5:57pm

https://www.boards.ie/discussion/comment/121490038#Comment_121490038

On what basis are you making that claim?

BlakeS94 · 13-12-2023 6:41pm

https://www.boards.ie/discussion/comment/121491940#Comment_121491940

Why is everyone so hostile on boards :,)

Correct me if I'm wrong anywhere,

Using WOT on a diesel tells the ECU to demand maximum output of diesel from the injectors. If say the fuel filter was blocked, the supply of fuel wouldn't be constant/consistent which would cause flat spots on the power band.

Or if an injector was leaking off too much diesel, which would cause a low fuel pressure scenario because the HPP couldn't maintain the high pressure needed.

I'm sure there's a few other things that could cause a loss of power, which is why I said "typically"

MK7R you're one of the members on here that's given me solid advice in the past for my own issue's I've posted, I'm just trying to do the same for somebody else.

Please feel free to enlighten me and the OP what could be more likely causing the issue

mk7r · 13-12-2023 9:21pm

https://www.boards.ie/discussion/comment/121492067#Comment_121492067

Ah there is no hostility it just seemed an odd claim to me 😅

If a fuel filter was to be blocked on a common rail diesel and the pump starved of fuel it would immediately throw a code and go into limp mode because it thinks there is a leak and a leak in the hp circuit can be quite dangerous so the tolerance is sensitive.

Same scenario for an injector that's leaking off too much, it won't cause a loss in power it would just immediately shut down once it hits the point where the pump can't deliver enough pressure anymore. (Fun fact, the early generations of common rail such as the 2.0 hdi used to just cut out no matter what speed you were driving when this happened, which was pretty dangerous in itself 😬)

And when you put you foot down for max throttle there is a list of lookup tables in the ECU (these are what get edited during a remap) so you might have throttle requesting 100% fuelling, mass air flow is at 50% and boost pressure is requesting 40% so in that scenario only 40% fuelling is delivered. There are many more lookup tables involved than those 3 but the lowest value is what gets delivered, as soon as boost rises to 50% assuming the maf hasn't changed then you get 50% of the 100% requested by the pedal.

There are many factors that can affect a car losing power but a fuel filter is almost never one in a common rail diesel.

alan8373 · 14-12-2023 7:39am

Thanks everyone. I've been told it the DPF needs clearing. Come up on diagnostic .

14-12-2023 11:00am

https://www.boards.ie/discussion/comment/121491866#Comment_121491866

Wrong size tyres or using a skinny spare could cause it to think a wheel is slipping

FortunaMan · 17-12-2023 10:49pm

I had the jerking issue on a 2010 qusaqhi when in cruise control. Also happened when I put the foot down on the motorway. Eventually I got an engine light and it was a turbo fault. I ran a few bottles of turbo cleaner additive through and it did the trick. I put one in every few months now and the fault hasn't come back.

alan8373 · 17-12-2023 10:51pm

Thanks fortunaMan

2014 nissan qashqai jerking in cruise control

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