Volvo v70 D3 2014 misfire/engine cutting off

[hpeter79]

Hi everyone, I'm a new member although I've been reading threads here for a while as a guest. I have trouble with my 2014 V70 D3 136 50k miles, I'm stuck now and not fancy to spend silly money just to find out the problem is not what I paid for.

The symptoms:
Car starts fine any time every time, no delay whatsoever however the engine sometimes shaking sometimes not. Reading with the Vida the fault is always 'Cylinder 5 misfire' tried to swap injectors in many patterns, cleared the code than driving the car it's always been the same after a short drive. Car cuts out constantly for a fraction of a second on easy acceleration and cruising, however perfectly fine on harsh accelerations and feels like it has full power, bit slower than expected to kick in but once it's there it goes well.

Sometimes it smokes after a few minutes for a little while, smoke is grey in colour and smells like spicy fuel?

Before it kicks in put the pedal down engine rattles badly, sounds like over fueling injector - probably is - but comes back to normal once the power comes. Power comes with some delay I believe, I'd expect the turbo come into life quicker.


What we've tried:
Injector swaps as mentioned above, no change, however injector no 5 was way worse looking than any of the others, burnt fuel deposit all around, not very bad in my view only when considering the rest of them were exceptionally clean. New washers used on final installation.

Leak off test, all injectors were ok running the car for about half an hour the difference between the most and the least leaking was sort of 15% cylinder 5 and the odd looking injector being somewhere between. When we removed the leak off connectors and started the engine (pipes and bottles reinstalled) a lot of fuel came though the leak off return pipe, from the pump. As I understand the leak off pipe connected to the fuel line between the tank pump and the high pressure pump feed side, so the tank pump should make the pressure there.

There is a small cylinder shaped plastic 'bean' on the return pipe assembly (part number 31321198 ) close to the connection to the fuel line what I was told by Volvo mechanic supposed to be a non return valve. Removing the whole leak off pipe I was able to blow and suck the air so I thought it might have been the problem I bought another one, but it worked the same was as the original one. I cut and opened one of these 'beans' and apparently it's a sort of resistor rather than a non return valve, two very fine filter and a small metal circle with a small - 0.2-0.3 mm - hole in the middle, clearly no moving part so it's not a valve its purpose is to make resistance in the pipe.

When the first time I removed the whole leak off pipe system to check and blow in, I put it back and the car was ok, drove it for about half an hour before stopped, only a tiny rattle for a second or so till the power came, I picked it up next day and it started the cuts again after a very short distance less than 5 minutes, and smoked for a minute or so when it started the cuts.

Before I received the new part and cut the old one I inserted a cheap one way valve off eBay, and the engine stopped cutting off for a little while till I believe the valve stopped working, as when it started cutting off again I checked the cheap valve and it didn't work anymore, a piece of rubber circle on a weak spring does the trick but the rubber moved and sort of smashed. I tried another valve but no luck with that one.

Also tried to divert the leak off return pipe into plastic bottle and left the one way valve on the pipe coming from the connection to the main fuel pipe, in which case no fuel came back to the injectors' direction and all the leak off collected separately instead sending into the main line, cut off still remains.

As the trouble is always with cylinder 5, and the leak off pipe designed that way all leak off goes through injector 5 the rest of the injectors joined to the main return pipe with a 'T' piece, I changed the design and inserted an extra 'T' piece into the system, using the old return pipe connector now the main stream not going through on injector 5, I thought the tank pump pushes fuel back into the injector causing either bad values so computer cuts the injection out or simply pushing fuel back to the injector and so the engine can only deal with this sort of mix once the pedal is all the way down, this theory obviously broke when I collected all the leak off fuel into the bottle.

Bought a second hand excellent looking injector from a reputable seller from a low mileage car just to try if that one makes any difference if I swap with injector 5 but no luck at all, same story.

This is all I can think of now, I'm sure I'll need to update it.
I'd really appreciate any idea what should I try or where to go with it.
Sorry if it's not 100% clear I'm actually writing it second time as computer decided to install the upgrades while I was on the phone.

Thanks in advance, all the best.

Peter

[GrahamBrown1]

When you fitted your new injector to number 5 was it coded to the car? This is done via a software upload with a Vida account not just the copy programme.

Have you checked the injector wiring and pins in the connector?

[hpeter79]

Hi Graham

Thanks for your time looking into my case.
No I haven't coded the injector, be honest I was actually convinced these bosch injectors don't need to be coded.

I checked the pins, any wire damage, removed and cleaned all connectors really related to the injectors with no change whatsoever.

The only time the synthoms had gone - only temporary though - when I was messing around with the leak off pipes.

My vida is a copy therefore I won't be able to program the spare injector, but the leak off test was OK so I put the old one back anyway.

During driving I tried to record live values of pump and injector related pressures and voltages whatever the Vida can do but I found it pretty useless without the knowledge what to look for and without the expected values.

Thank you
Peter

[Globalscouse]

Hi, I seem to have a similar issue that no one seems to be able to fix. Had a new EGR valve fitted but the car still missfires and on low revs sounds as if its over fuelling (actually sounds like all the head gear is loose)/ Injectors have been checked but all ok. about to be sent to a 3rd garage as the last two have exhausted all their knowledge.

Did you ever find your fault?