Engine: B5244: What i did this weekend (intake gunk cleaning)...

[aspireofbrixham]

So, 2007 V70 Mk11 2.4D (163PS EuroIV) with a couple of issues that despite forum searches and scanning the latest 600+ threads I haven't exactly come across any insight in to.

I've known the car from new, full Volvo service history for first 70K, annual services thereafter, generally changing oil well before specified miles. When I was doing high miles it would get changed twice a year, typically 9 - 13k. Always specified oil, and usually genuine filters and parts. Now 195K miles.

Recently resumed doing my own service and repair work since a new job means 1. I don't have money to burn, and 2. I actually have time to 'get a life'.

Serviced and brakes done (front rotors and pads, rear, added handbrake adjusters) in January to get it through the MOT (Pass 1st attempt, no advisories). Only thing ommited at service was fuel filter 'cos the plastic casing would not budge - ordered a tool. In any case, the filter has been changed every 2 years typically and never been bad.

A month ago the throttle resopnse went to rats, sticky response to throttle inputs, idle held high, typically around 1500rpm. Holts egr / carb cleaner was forced down it's throat and all returned to normal.

Problem returned last weekend, with nailed on consistent faults -
1. Idle perfect from cold, 1500rmp when warmed up.
2. Sticky throttle response, sometimes taking 3 seconds to respond to foot inputs.
(from cold, drove perfectly, instant response and no lack of power. No engine warnings, no fault codes on Torque Lite)
EGR cleaner made no difference.
One characteristic I did find was that by holding down the brake when stationary, the revs would drop over a period of 20 seconds or so, back to rock steady 700rpm.

Vacuum issue I immediately thought.

Filter tool arrived this week so ran fuel low in anticipation of changing filter. Left car on a slope on Wednesday and it wouldn't start. 10 year old battery died so new Yuesa Battery fitted from Halfords and 10 lit of fuel from a can resolved that one. Next day car ran perfectly once fuel had fully bled itself. Wondered if disconnecting battery might have reset something? Following day, all symptoms returned - pants!

Changed fuel filter on Friday with no trouble - advice, get the £20 tool off ebay / Amazon, turns a B of a job into a piece of cake. Had a bit of slow starting / uneven running thereafter which I will assign to air in the system. All other symptoms unchanged.

Had the vac gauge on it this w/e and found front engine mount holds max 12" but drops fairly quickly. Rear - can't really get at it but the pipe from the front was showing zero. The engine mount control valve was showing a steady 25" at idle (when tickover was actually slow enough), dropping to zero vacuum when reved over 1500. Put a blank end on the engine mount outlet of control valve and tested the vacuum pump - 25" from aux circuit, very strong vac from brake circuit (too much for 30" Mity vac tester, nearly bit my finger off!) All other connected pipes I could find held a 25" vacuum.

Did recommended vac pump / brake booster / check valve test (engine on / off, pumping pedal, holding down, waiting 1 min, restarting, pedal sinking etc. All to spec.

With engine mounts out of the circuit, took a test drive, and once warmed up, fast idle / sticky throttle returned - still pants!

Disantled inlet as far as butterfly valve which was a bit sticky, cleaned this immaculately, added a bit of oil to the spiggots til it was moving smoothly against it's return spring. Cleaned EGR mixer plenum (for want of a better term) in situ until very clean indeed (unlike me by this stage).

Put it all back together, congratulated myself that it started, and went for a shortish test drive and after a few coughs (maybe a bit of air still in fuel system I thought), all seemed to be back to spec. Then went for a longer test drive on motorway and all symptoms returned - big, baggy, pants!

Wondered if the fact that battery disconnected and main ecu removal to get at inlet tract to clean, might be responsible for temporary good behaviour until it learned how to be bad again?

(Still no fault codes on Toque Lite incidentally.)

Washed my hands a hundred times and went to bed with ipad to do more forum searches - to no avail.

Went out in car this morning and everything seems perfect. Tickover nailed on 700rpm at all times, no delays in throttle, pulling good and strong - appears fixed.

As there are many calls for help posted on here which often omit to reveal the outcome, I thought I would make sure I would reveal the answer.....

Sleep on it!!! (no doubt I will be back next week, but fingers crossed eh?

Meanwhile, lots of mentions of Torque App on here, but Car Scanner seems to give lots more info for my car. However, neither are showing any fault codes as a result of these issues, or anything else, bearing in mind i have had a flat battery which experience suggests throws up loads. Car scanner advises none in last 45000 miles.

My main question is, the inlet plenum (egr mixer) has a vacuum supply to a control valve (with electrical connection - looks similar to engine mount control valve) on top of unit. Vac outlet disappears underneath. Applying Mity vac up to 25" causes an invisible control arm to move on underside, springs back when pressure released.

Anybody know what this is / does and if there are any diagnostic tests?

Second question is, are there any instructions / help / pictures etc. for getting the EGR cooler off this engine? I didn't do the gynacology course and wondered just how much needs dismantling to get the next stage of this system cleaned out, and where the hidden fasteners are?

If you read this far... thank you!

[colinbos]

You still need access to VIDA to correctly tell if you have any Diagnostic Trouble Codes, and to rest them if needed. The app isn't enough to make sure the car is right.

Good job though, we've all been up to are elbows in that crud.

Once a year job for me now, to keep on top of it.

[aspireofbrixham]

Hi Colinbos, just wondered if you’ve had the egr cooler off yours and what’s the procedure? I’m guessing it’s the same or very similar to mine?

[petey]

I took the EGR heat exchanger off of my friend’s XC60 D3 and once you get the inlet pipes and throttle off of it, it wasn’t so hard. There’s an annoying T30 torx bolt near the back that’s easy to miss but the real strain is the two 10mm nuts where it joins the exhaust manifold. The top was ok, but the lower one is a b’tard to get at with the engine in situ.

VIDA will have the process (with sketchomatic super low quality pencil images) for your specific engine.

[colinbos]

Originally Posted by aspireofbrixham

Hi Colinbos, just wondered if you’ve had the egr cooler off yours and what’s the procedure? I’m guessing it’s the same or very similar to mine?

Nah. At the time it looked to time consuming for me. So I bought a Wynns EGR cleaner and sprayed it as per the instructions. After each spray I could hear the EGR knocking it nuts off, and I imagine it was knocking the carbon off too.

Anyway, Ive got/had no issues, so apart from keeping the intake and ETM clean, Ive left alone.