V70: Engine Hello all v70 d5 misfire

[saltyjim]

Hi guys,

Sorry long weekend.

So I have looked underneath and had it running to visually check for any boost leaks into the plumbing under the car. Equally smoke tested it again today via the air intake and found a small air leak on intake on the pcv nipple but I highly doubt that would be causing the issue although obviously I will seal it up anyway to make sure .

A live read at the stutter point is a good idea to try and see what is happening, as I say I have checked the wiring resistance of each injector wire at the connectors so don't think it is that and they have been thoroughly cleaned.

How do you get to fuel trims in vida I havent come across that one yet ? Still learning how to use it all.

Beginning to wonder if there is something wrong with the ecu.. is there any way to tell if someone has tried to put a funny map or something on it and messed it up like that ?? Just an idea

[saltyjim]

Also checked turbo actuator from underneath with someone revving it above me and hoping it didn't fall on my head .. and it seems to be working very well

[camturbo]

What does the rev counter show at idle and is there any fluctuation? Is manual or auto could it be slippage

[37 RUBY]

With regards fuel trim, I've just read an interesting article in relation to this.

It would seem that the long term fuel trim (ltft) values adapt to what the sensors are doing, engine wear, fuel pressure changes, injector wear and so on.

If a sensor begin to operate at the outer edges of its parameters or it begins to fail, the ltft values shift to accomodate.

What they don't do is automatically return to base line values even though the errant component is replaced.

That needs a reset. Some vehicles such as BMW's need a hard reset using software, some including some Volvo's need a soft reset, ie disconnect the battery and discharge the system by say operating the brake pedal and leaving it disconnected long enough.

Upon reconnection and start up a drive out to allow the ltft values to adapt to the new hardware, ie replacement MAF, MAP sensor etc...

I know that is way out there in the scheme of things and I'm ready to be shot down in flames but it's worth a try and costs nothing.

[saltyjim]

Hi guys just spent more time on it again this afternoon, took ecu out and checked all pins for corrosion and checked loom.. None there but cleaned anyway. It is a 6 speed manual and no slippage, it seems to be almost running rich if that makes sense which is what I think is causing it to bog down at low engine speeds under load whereas when you are on boost it can clear it. Thats my theory anyway, just don't know why. Triple checked all air intake pipework with pressurised smoke machine and made sure there are 0 air leaks anywhere. Also while ecu was out battery was off for an extended period so hopefully that reset the trims ? Again didnt seem to make a difference at idle it seems to be fairly smooth and consistent idling around 800, its only when you blip the throttle do then you feel the shuddering/ misfire which obviously you feel also when out on the road, seems to be around 1200-1800 it shudders misses etc and then it clears. I wonder if there is anyway to force a fuel trim reset. And I wonder also how.much volvo charge to flash a stock map back onto it in case it is that.

[37 RUBY]

within this post - https://www.volvoforums.org.uk/showthread.php?t=217209
there are three conclusions for owners suffering similar to you.

1. Fuel filter issue. I know you changed this but perhaps revisit to check for a leak at the
filter head or blocked filter from excess debris

2. Split vacuum hose somewhere. You could include leaking engine mounts (If applicable).

3. Chaffed wiring under air box

[camturbo]

Mine is 07 euro 4 185 and it sits bang on 700 revs at idle if you blip the throttle its smooth. Not sure if there is an accelerator sensor/switch on the pedal that maybe out. Not sure if there is such a thing eh! Is there a way on vida to see if it is ideling properly. Only a thought. You seem fairly clued up on cars.

[saltyjim]

Thanks all for your replies I really do appreciate them. I will try anything at this point, I'm going to get it on vida again and see what its showing and have a good old dig about again
Annoyingly I have been trying different things so no doubt it will give me erroneous codes where I have been messing but still I need to focus on the live data to see what should be normal. Mine certainly isn't smooth at all if blipped, stutters and shudders. And I can certainly recheck filter, although previous one I took out seemed in very good condition so not sure it has a blockage but as you say worth another check. Checked vacuum by physically sucking on the end of it and its definitely holding vacuum ( i know im weird) .. wiring is definitely worth a check though for sure thank you

[37 RUBY]

Originally Posted by saltyjim

Checked vacuum by physically sucking on the end of it and its definitely holding vacuum

Whilst your ingenuity is to be admired, I do think a cheap vacuum gauge is in order here.

You can then at least monitor for a consistent or fluctuating vacuum.

[saltyjim]

This is true, I will have a look to see if I can get a good cheap one