2.4 Tdci, 120,000 miles.

Twice now a month or so apart having come off the dual carriageway and around a few roundabouts I've lost a lot of power. Throttle flat to the floor, 3500 revs and no torque. Struggling up the hills. Thought turbo may be playing up but no strange noises, no split hoses etc.

Had a nose around on here and I think it may be the VCV? No warning light bringing up a fault code.

Is the VCV the logical place to start?

If it is, is it best to go for genuine or are aftermarket ok? Is there any real difference?

Thanks

Yes, do you know how old it is?

It would be useful to plug it in to check for any fault codes. (DTC’s).

Bearing in mind the VCV doesn’t produce any but MAF and other items do.

Might be worth cleaning the MAP and MAF sensors too.

I got my VCV from PF Jones diesel specialist, the part fits various models mine came in a Nissan genuine box.
The part was brand new, fitted and really good.
The biggest different you’ll notice is high end power restored.

You are probably getting some fuel starvation at higher speeds hence the issues you’ve had.
It will get worse and can just cut right out, especially dangerous at junctions and roundabouts as this happened to me twice.

No programming required once fitted, however, I would recommend to disconnect battery first before working on it which is good practice.

There is a two stage tightening process of the fixings in the WSM with torque settings if you can get that, or it’s may be on here or it can be looked up for you.
If you would like to not do that or you don’t have the tools. Just don’t over tighten, they are just nipped up.
Not loose, but don’t over tighten tighten.
Just secured.

IIRC is was 8nm max possibly 6nm, but don’t quote me on that, it’s a relatively simple job and the electrical connector is best removed once the part is removed for ease of access.

Worth having a bit of paper / kitchen towel and disposable gloves if you have any lying around too.

I find mine is running very sweet now, full power is restored and you will notice the difference.  Diesels Lives Matter

Thanks Steve

Don't rule out turbo. Does it reset with an ignition cycle? Cheers

James
110 XS Utility
130 Puma Station wagon/camper (in the making)
90 Puma Hardtop

James is right above, so worth doing some checks but seeing as the VCV is relatively cheap it’s worth doing and can then be ruled out if it isn’t the issue in the end.

Good luck.  Diesels Lives Matter

jst wrote:

Don't rule out turbo. Does it reset with an ignition cycle?

Does it always happen after coming off boost only? Cheers

James
110 XS Utility
130 Puma Station wagon/camper (in the making)
90 Puma Hardtop

I have the same problem. It only happens rarely. Temporary fix is to switch the ignition off and on again. So I am following with some interest.

Similar problem here, same engine, same mileage. I think mine is turbo related as when the power goes there is no longer that distinctive whistle from the turbo. Engine off and cool down - off we go again.

I've spoken to the guys at Bass tuning and need to wait until it happens again and plug in the code reader before turning off the ignition. Will keep you posted

My fix was - new fuel filter (full of crap, so fixed breather pipe first), foamy turbo cleaner thru turbo and a new vcv. No probs since, and was occurring every few days beforehand. Prob belt and braces but covered all bases for me 👍 2.4TDCI 90 - everyday brilliance
S3 V8 Lightweight - in the garage being ignored #newchassistime
S3 lightweight - 2nd car 24V fire risk with a full tilt and the windscreen down
S1 80" - first car fun - 75mph in neutral downhill once #wobblesallround

i have had the fuel tank breather issue, but that cures itself once you have slowed down and some air has made its way into the tank then it goes again.

i think you have a turbo overboost register issue which is going to limp mode, assuming it does it after a longish session on full load/boost.

try holding it under full boost for 5 to 10s, ie uphill on a motorway and see if it does it. Cheers

James
110 XS Utility
130 Puma Station wagon/camper (in the making)
90 Puma Hardtop

Is the actuator operating smoothly too? Diesels Lives Matter

^^^ i expect it is moving but not responding quick enough when coming off power and pressure ouput correlation is lost. Cheers

James
110 XS Utility
130 Puma Station wagon/camper (in the making)
90 Puma Hardtop

That makes lot of sense. I tend to put a drip or two of oil on mine (turbo actuator) every once in a while. Like 3in1 oil in a dropper bottle.
Only very little though for obvious reasons and seems to keep mine in good order. Diesels Lives Matter