[NoControl]

Originally Posted by BikerChrisV70

Thanks Mike
I have a V70 D5 163bhp 2004 with around 115k. I had the dreaded ECM6805 code diagnosed by a local garage but they weren’t sure how to resolve the issue as Volvos are not their specialism. Booked the car in with the main dealer who confirmed the code running a diagnostics and investigation (costing £60) to test the vac lines which showed no issues and suggested I rebook the car in for a further diagnostics assessment by the Master Technician (who was on holiday at the time of the first visit). I declined their offer of paying a further £100 and decided to carry out searches on the web and I landed at the Volvo Forum. I came across your post with what seemed to be a very useful guide/checklist to work through which would hopefully eliminate the problem and restore the V70 D5 back to its former best. I am not a mechanic and am going through a steep learning curve.
As I was on a tight budget, the first job I decided to tackle bizarrely (for the cost of the gasket set) was to get the turbo out and give the internals a de-coke. Having read up how to do it (I did find a really good set of step by step instructions) ... how hard could it be! 12 hours later job done. Fire up the engine, sounds fine and took car for a spin. Wonderful, accelerate hard and pulled like a train. Revved well past the 2500rpm problem point and no sign of any problems ... for about 3 weeks. Then the problem came back. That was last October. More surfing the web as a result.
I have recently invested some more time and money trying resolve the problem including the following new parts:
1. New Turbo Control Governor (operating the turbo actuator)
2. New Turbo Control Valve (for the engine mounts)
3. All the small bore rubber vacuum pipes replaced with silicone hoses (used 5mm int dia).
I have invested in a Mity Vac as identified in your article to check all the vac pipe pressures and this is now where I hit a strange anomaly. According to your article the main vac pressure at idle should be around 45 Hg. My Mity vac only goes up to 30 Hg but I only get an idle pressure of 22 Hg. Revving up to 2500rpm this figure rises slightly to 24.5 Hg and doesn’t go any higher.
Using the Mity in line between the TCV and the engine mount at idle is 22 Hg (which give the softer engine mounts). Increasing the revs above around 1100rpm the reading drops to 0 Hg (meaning harder mounts) and doesn’t change once over 1200rpm.
Working from underneath (it seemed easier) I connected directly to the VNT and the arm moves pretty smoothly in and out using the Mity vac. I did this several times just to make sure. Then connecting the Mity in line with the VNT I get the following readings. At idle 22 Hg, at 1500rpm 21Hg, at 2000rpm 14 Hg, 2500rpm 11 Hg, 3000rpm 8 Hg and at 3500rpm around 6 Hg. It is these readings on the VNT side of the TCG that baffle me. The article I says the reading at idle is 5Hg, at 2000rpm 43Hg and at 2500rpm 35Hg. My readings seem to do the complete opposite curve.
I thought I was very systematic in changing all the vac pipes by only changing one length at a time to avoid mixing up which vac pipe connected to the inlet and outlet ports on the TCV and TCG. Is it possible that I have still managed to transpose them somehow? For ease of identification I even used different colour silicone hoses for the turbo pipe and vac inlet.
A test run in the car after changing the vac lines, TCG and TCV has made no difference under hard acceleration. Under very gentle acceleration building up the revs in 4th very very slowly on a long stretch of dual carriageway we got to 3500rpm with no issues. Once I had eased off and then tried to overtake ‘with gusto’ same old problem .... instant limp mode which is real a problem halfway through overtaking!
The next item on the list to change seems to be the turbo fresh air intake hose. My local dealer has offered me the bottom hose only for a mere £74 or the entire hose from the air box to the turbo for £93 including the metal section. To ease the pain (his words) he was prepared to offer a 10% discount to me. I have seen the bottom hose (not OEM) on Ebay for £28. The dealer also said he often sells a sensor (£93) on the intercooler outlet pipe at the same time when people are replacing the turbo air inlet pipes. I’ve not seen any mention of this on any of the posts that I have read. Anybody come across this one?
Any help, comments or advice on any of the above would be appreciated. I’m running out of ideas (and money) to resolve this matter to a successful conclusion.

Have you sorted out the TCG readings, because I got the same results what were opposite with the Mike readings?