[zak]

Are you certain then that its a misfire? Have heard of cam journals getting worn out at low mileage

 

[Markm87]

UK laws are different, but within 6 months, maybe. I think they updated protection on used cars like some states here do.

As you say UK laws are different unfortunately, not so much protection for the consumer instead favouring the business.

 

[Markm87]

What buggles my mind about these giant car companies. How do they not have a knowledge base of videos and advices from different problems of their cars from around the world.... With video and probably solution or flow charts especially if it goes to techs at headquarters. I'm pretty sure that is not the first time this problem arises. And the incompetent techs at the dealers are unreal....
My brother in law just took his ram truck to dealer for 4wd service light under warranty.. Charged him $900 . Two days later the light came back.. went there they wanted to charge him some more....

The vip warranty for example should require video evidence and steps took to diagnose..

I completely agree, this can't be the only Volvo with this problem ever. I would be surprised if there isn't already some sort of Volvo knowledge base linking specific symptoms to faults, I wouldn't be surprised however if the dealerships aren't aware of it or simply choose not to make use of it.

 

[Markm87]

Can you list all of the codes that you have seen and that the Volvo dealership has recorded? Since you purchased the car used 6 months ago any ideal about past repair history? I am not sure about your market, here in the US, Volvo is very helpful about diagnosing problems like this. Any idea if the dealership has inspected the spark plus for being worn out, loose or have installed a new set? The injectors could be an issue or high pressure fuel pump?. If the engine has had internal repairs, it is possible that the balance shaft backlash was not adjusted properly. Below is a pic of the balance shaft assembly. The balance shaft assembly will cause engine shake, not sure about the misfire codes.
You may have more that 1 problem. Hopefully the dealer and Volvo will get this corrected.
---------------------
The task of the balancer shafts is to smooth out the engine's oscillations and they are driven by a gear on the crankshaft. The two counter-rotating balancer shafts are located in their own housing in the oil sump. Drive to the balancer shafts is via the crankshaft to one balance shaft, which in turn drives the second balance shaft. One of the balancer shafts' gears is two-piece. The "narrow" half (Scissor gear) is spring tensioned in the opposite direction to the "wide" half. It provides silent backlash elimination. This technology is already found in the gear on engine B63x4x. To ensure correct backlash, the balance shaft housing is shimmed to the engine block at the assembly plant.

View attachment 187955 View attachment 187956

The dealership have told me they have not seen any fault codes. As for the history, I have requested this from Volvo but they are only able to share service history, and from this I can see it has been serviced by Volvo at regular intervals since new. I asked the dealership to show me any other history on their database and this only included software updates etc. no record of previous repair work.

In the last 6 months, in attempt to resolve the problem, the dealership has done the following that I am aware of:

• Changed Crankshaft Pulley, Auxiliary Belt & Tensioner - This made no difference.
• Changed Spark Plugs - This made no difference.
• Changed 1x Coil Pack - This made no difference.
• Performed Compression Test - All OK (At the time they mentioned if anything it was very slightly higher than expected)
• Checked Cambelt Tensioner & Timing - Tensioner slightly under tensioned, otherwise all OK, no difference after adjustment.
• Observed a small amount of milky fluid on oil filler cap (suspected due to short journeys in the winter months, disappears after a slightly longer journeys)
• Removed interior carpet to check for water ingress - No sign of water.
• Removed ECU and various other components to check for water ingress - No sign of water.
• Observed random misfires on all four cylinders.

That's an interesting point regarding the balance shaft, I will have a read into this.

 

[orcking]

The dealership have told me they have not seen any fault codes. As for the history, I have requested this from Volvo but they are only able to share service history, and from this I can see it has been serviced by Volvo at regular intervals since new. I asked the dealership to show me any other history on their database and this only included software updates etc. no record of previous repair work.

In the last 6 months, in attempt to resolve the problem, the dealership has done the following that I am aware of:

• Changed Crankshaft Pulley, Auxiliary Belt & Tensioner - This made no difference.
• Changed Spark Plugs - This made no difference.
• Changed 1x Coil Pack - This made no difference.
• Performed Compression Test - All OK (At the time they mentioned if anything it was very slightly higher than expected)
• Checked Cambelt Tensioner & Timing - Tensioner slightly under tensioned, otherwise all OK, no difference after adjustment.
• Observed a small amount of milky fluid on oil filler cap (suspected due to short journeys in the winter months, disappears after a slightly longer journeys)
• Removed interior carpet to check for water ingress - No sign of water.
• Removed ECU and various other components to check for water ingress - No sign of water.
• Observed random misfires on all four cylinders.

That's an interesting point regarding the balance shaft, I will have a read into this.

Wow....
Misfire is either a mechanical issue or ignition fuel delivery issue ...
Did they do compression test?
It could be that the timing is off? Are the valves bent?
How could they not find the issue after 6 months is beyond me. I'm not a mechanic but I think logically. Mechanics 101...
If they just change parts and cross their figures they are incompetant.
Find a mechanic that knows what they are doing like scoty kilmer or the carcarenut

 

[BolboLubber]

How's the battery? How old is it? (there should be a date code on it).

 

[Markm87]

Are you certain then that its a misfire? Have heard of cam journals getting worn out at low mileage

I think there is more to it than just a misfire, certainly.

I don't believe the noise itself to be a misfire as it makes the noise almost continuously whilst driving around town, logging misfires randomly. It's possible to drive around for a few minutes when the noise is clearly there, without having logged any misfires.

My guess is that whatever is making the noise is also causing the misfires?

I have wondered a few times if it could be the knock sensor sensitivity, with the ECU advancing timing too far because it doesn't detect knock. Apparently this has been checked though.

 

[Markm87]

Wow....
Misfire is either a mechanical issue or ignition fuel delivery issue ...
Did they do compression test?
It could be that the timing is off? Are the valves bent?
How could they not find the issue after 6 months is beyond me. I'm not a mechanic but I think logically. Mechanics 101...
If they just change parts and cross their figures they are incompetant.
Find a mechanic that knows what they are doing like scoty kilmer or the carcarenut

The Volvo techs said they have done a compression test and was all ok.

They checked the timing belt and at the time suggested it could be a vvt solenoid but didn't change them as there was not enough evidence to justify changing then under the warranty!

 

[Markm87]

How's the battery? How old is it? (there should be a date code on it).

This has crossed my mind, I don't really understand how this all works with the hybrid system though.

Which battery sources current for spark plugs etc. is it the standard 12v battery or is this derived from the high voltage battery, or both? I don't believe there is a standard alternator driven from the auxiliary belt, so assume the high voltage battery system also charges the 12v battery?

I will check the 12v battery voltage later today though.

 

[Dyno]

Look for odd behavior in manifold pressure, fuel pressure, timing, coolant temperature, pedal position, etc.

It's been a long time since I've done this and I'm not a pro, but in the US at least, a Freeze Frame is recorded at the moment a fault occurs. That would be valuable. I don't know if happens when a fault occurrence happens, or when a fault code is set. Two different things.

 

[Pioneer4x4]

I'll chuck a W.A.G. out there. Loose mounting of crankshaft to transmission components/ISG type area. Something loose in ISG itself maybe. Or something like the supercharger way loose/out of balance.
Only because all the obvious stuff seems done already. No matter what, it really seems mechanical, but then it can go away...

 

[Markm87]

How's the battery? How old is it? (there should be a date code on it).

Checked the battery voltage today, after being parked for a while it was at 12.7V so that looks ok to me.

 

[Markm87]

Look for odd behavior in manifold pressure, fuel pressure, timing, coolant temperature, pedal position, etc.

It's been a long time since I've done this and I'm not a pro, but in the US at least, a Freeze Frame is recorded at the moment a fault occurs. That would be valuable. I don't know if happens when a fault occurrence happens, or when a fault code is set. Two different things.

View attachment 188054

The Freeze Frame data would be really useful. I have used this before to help diagnose problems on my previous Audi's and it always worked well.

I don't quite understand why no fault codes are being logged here though, I am sure there is a threshold to allow the odd misfire to slip through without a code but surely several per cylinder, per journey, should flag something in the ECU? It would be great to find out what the threshold is.

 

[Markm87]

I'll chuck a W.A.G. out there. Loose mounting of crankshaft to transmission components/ISG type area. Something loose in ISG itself maybe. Or something like the supercharger way loose/out of balance.
Only because all the obvious stuff seems done already. No matter what, it really seems mechanical, but then it can go away...

I haven't considered ISG before, however I did suspect the supercharger for a while as the noise seems to disappear at higher RPM and i know the supercharger disconnects at 3.5K RPM.

These are probably both quite difficult parts to check mechanically without first removing many other components and so the dealership will probably be reluctant to do so without good reason to suspect them, not sure if there is any easier way to check these?

 

[Markm87]

I managed to capture some data from various sensors during the first few minutes of starting the engine.

The vertical red line shows the transition between the two symptoms, to the left of the line is when the noise/shake will be apparent as shown in the video on my original post, to the red of the red line will be when the knocking noise under load whilst driving would be apparent.

As I said previously, I believe this transition to be when the ECU switches between open/closed loop feedback, although I may be wrong so be good if someone can confirm this.

If i am correct then the ECU will most likely be running some default map initially then to the right of the red line is when it starts to use the vast array of sensors to make adjustments.

It would be really great if someone else with a T8 and an ELM327 OBDII dongle could run a similar capture for comparison though.

 

[Glennda5id]

Take an oil sample and mail to blackstone labs.

 

[Tank010]

Maybe it would be better at the bottom of a deep lake?

 

[Peter1234]

There is indeed a sharp change in some parameters. If the noise is related to recharging of the hybrid battery, you should monitor the BECM HV battery current and voltage. Maybe some hybrid components cause this issue?

Any ECM misfires cyl 1 - 2 - 3 - 4, and total?

Please check and post screenshots of the Noncontinuos Monitors and the Emission Tests in the OBD2 app, maybe there are some clues...

 

[831t5r]

That sucks. You have an obvious issue. I would have replaced injectors in a heart beat under warranty since they fail so much and cause misfires or fuel trim issues if compression/leakdown are good and misfire counters go crazy with good compression

 

[Pioneer4x4]

...It would be really great if someone else with a T8 and an ELM327 OBDII dongle could run a similar capture for comparison though.
...

How do I do that? I have several different dongles.