V70: Engine D3 hesitation

[tommyweaves]

My MY2011 D3 163 manual (105k miles, FVSH) has developed 2 distinct scenarios where there is a momentary hesitation in acceleration.

I first noticed something about a month ago: In urban driving when coming out of a sharp corner at 1500rpm in third gear the engine seems to lose power for about a second and then carries on just fine. Can't seem to replicate it in lower gears at the same revs.

Then last weekend on a long motorway journey I noticed the car hesitating for a couple of seconds when accelerating in 6th at about 1900 2100rpm. I could get it to replicate at similar rpm accelerating in fifth gear.

In all othe driving scenarios it goes as well as it always has.

In both scenarios it was high load (i.e. foot down) with lowish revs. The symptoms can best be described as "bogging down", as if it was under fuelling.

No Engine service lights or anything. Starts fine, tickover fine.

Before I ask my local Volvo dealer to look for any fault codes does anyone have any experience of something similar, ideas etc?

[cheshired5]

The description could feasibly be a boost issue or an ABS/traction control problem momentarily reducing power but if you have no diagnostics whatsoever, troubleshooting could be problematic.

I would find a nice clear stretch of road, stick it in 4th gear around 35-40mph, hover at that speed for about 10 seconds then floor it to see if it pulls continuously through to high revs then repeat.

[tommyweaves]

Thanks SiRobb. Was thinking similar on the boost issue. Doesn't feel like an ABS issue but interesting one I hadn't thought of.

Is it likely I'll have some sort of fault code stored that might give an indication of the issue?

[cheshired5]

You won't necessarily get a fault code.
Systems can misbehave but not "know" that they're misbehaving so no warnings or codes appear.

Live boost data, preferably in graph form would show up a boost loss or erratic boost behaviour and the cheap ELM327 dongles + a phone app can be good enough to show that.

[tommyweaves]

That's what I thought on the fault codes so thanks for confirming a similar view before I spent money at the dealer.

The boost from the turbo must be physically there otherwise it would need to respool before picking up again - and to have boost and then lose it again momentarily doesn't make sense. So I'm thinking boost sensor/MAF (or whatever gubbins is involved on the "air side") or something on the injector/fuelling side.

It has to be an ancillary component like ETM, EGR, TCV, MAF etc that's having a hiccup. The question is where to start!

If after following your suggestion of doing a steady 35-40 in 4th and then hoofing it, and it hesitated at some point, replicating the issue, what would that indicate?

[cheshired5]

Originally Posted by tommyweaves

If after following your suggestion of doing a steady 35-40 in 4th and then hoofing it, and it hesitated at some point, replicating the issue, what would that indicate?

Boost leak, sticky VNT plus others.
Diagnostics are the key though.

[tommyweaves]

Originally Posted by cheshired5

Live boost data, preferably in graph form would show up a boost loss or erratic boost behaviour and the cheap ELM327 dongles + a phone app can be good enough to show that.

If I understand correctly I can get a live readout of engine data with this? If that's the case it's definitely worth having a look!

Do you have any recommendations for ELM327 bluetooth dongles and apps?

[seanc]

Originally Posted by tommyweaves

My MY2011 D3 163 manual (105k miles, FVSH) has developed 2 distinct scenarios where there is a momentary hesitation in acceleration.

I first noticed something about a month ago: In urban driving when coming out of a sharp corner at 1500rpm in third gear the engine seems to lose power for about a second and then carries on just fine. Can't seem to replicate it in lower gears at the same revs.

Then last weekend on a long motorway journey I noticed the car hesitating for a couple of seconds when accelerating in 6th at about 1900 2100rpm. I could get it to replicate at similar rpm accelerating in fifth gear.

In all othe driving scenarios it goes as well as it always has.

In both scenarios it was high load (i.e. foot down) with lowish revs. The symptoms can best be described as "bogging down", as if it was under fuelling.

No Engine service lights or anything. Starts fine, tickover fine.

Before I ask my local Volvo dealer to look for any fault codes does anyone have any experience of something similar, ideas etc?

I've an auto D3 S80, just had the turbo pipe replaced (94500 miles) as it split on a bend, the one near the airbox I think.
It had started hissing and feeling a bit lumpy for a week or two, before it logged a fault and went into limp mode, but before that would otherwise boost and drive normally.

[cheshired5]

Originally Posted by tommyweaves

If I understand correctly I can get a live readout of engine data with this? If that's the case it's definitely worth having a look!

Do you have any recommendations for ELM327 bluetooth dongles and apps?

I'm on Android and use the mini Bluetooth ELM327 version 1.5 and the Torque Pro app.
£8 total and I get live engine data on my phone which looks like this.....



ios needs a WiFi ELM327 and an iTunes app like Dash Command.

[tommyweaves]

Excellent, thanks. At £8 I can't believe this approach to initial diagnostics isn't discussed on the forum more often!