Might as well do an update.

Solved the problem as of 3 weeks ago.

Found the rear mount was leaking (front already replace), TCV was changed, Boost pressure sensor changed and a replacement turbo.

All vac tested and smoke tested again, no problems visible and no codes.

Car is now quieter, averaging 2 mpg more on my 10 mile commute.

So hopefully that is that.

Lesson learnt: On a car thats 13 years old, change the lot, dont mess around with bits here and there. You may save a few pennies in the short term but its all going to need changing at that age.

Hi so if it was the mount that was bad,
why did you get a new turbo,tcv,map sensor, why did you not test it, it would have saved a lot of cash,
Dave

Simple answer to that my friend,

The turbo was sooted up where it would occasionally stick causing overboost. And no I was not going to go to the trouble of stripping and cleaning and the potential of have something else go wrong with it.

It also had the seals on the cold side leaking a little oil into the intake.

The TCV was marginal, in that it was not operating properly from time to time and the boost pressure sensor was just a matter of course.

So everything really needed some maintenance/replacement.

The rear mount was not leaking last year, but this year it was.

I had to take the decision to throw in the towel and get another car or dump some cash at it (for a lot less than a second hand car) and run it another couple of years.

So thats what I did.

Like I said, it runs smoother, it has less noise and better mpg and no recurring limp mode.

good that it is all sorted now,
my vacuum mounts have not got yet, but mine is an 2002 so I will keep my fingers crossed,
on a turbo car there will always be some oil in the intake pipes, but not bad, and that is where Volvo put the oil breather pipe,

Dave

I have been living this nightmare since Christmas, and tested everything - replaced a leaking front mount but didn't fix the problem, I bit the bullet and swapped the turbo for a known good one - and hey presto the engine service and limp mode has gone.

I will probably take the turbo apart at some point to see what the cause was - as mine too only did it when it was cold.

Thanks to this forum and SiRobb videos online as without them I wouldn't have managed to find the fault and didn't want to go buying Vida etc.

Worth mentioning that I managed to get the turbo out through the top also without removing the engine - although with the time taken I would argue it probably doesn't save too much time and if I were to do it again (prey not) I would lift the engine out - trying to get the two small screws in for the oil pipe when crawling underneath is a real PITA.

So it's my turn to battle the dreaded 6805 issue. Mine is very intermittent. It throws the 'ENGINE SERVICE REQUIRED' message and goes in to limp generally on the first hard acceleration of the day on a cold engine. If I creep up to 70mph in limp mode (it takes ages) the message will go away and power is restored for hundreds of miles!

I have no other faults whatsoever in VIDA, just the ECM-6805.
I've checked:

• Good Italian tune up done, although it generally gets a decent run and I use the performance, so it's not coked up
• Engine mounts hold vacuum for hours
• I've tested every single vacuum line on the car and they all hold vacuum
• Replaced the vacuum solenoid on the air box (I had a spare)
• Turbo actuator holds vacuum and it feels like it moves freely
• I've checked all the boost hoses off the car and they all seem pukka.
• 1 injector was very slightly over range at 3.2mm3(spec is 3mm3) so I replaced it and now all injectors are reading very nicely indeed.
• Turbo control valve (near the EGR) has been removed, inspected and cleaned. The diaphragm appears perfect.
• The accessible EGR pipework has been cleaned, although it really wasn't bad.
• The intercooler was replaced with a genuine Volvo new item about 2 years ago so I'm confident it's not that, and there's no signs of leaks.
• The car is well serviced (every 8k or so) and a major service including diesel filter was done 5k miles ago.

Other that when it goes into limp it drives fantastic, it's smooth and feels as powerful as ever. I can't see any smoke etc.

I'm really scratching my head now, and frustratingly it doesn't happen consistently and every time I put VIDA on to do some logging it behaves perfectly :angry_smile:.

Any ideas what to check next? I don't really want to throw parts at it on a whim. I think there's something in it being the first hard acceleration from cold, but the temp sensors read correctly etc., and ambient temps have been pretty warm. :confused_smile:

Any help appreciated!

Ok, so I managed to get some logs this morning.

Injectors reading perfect.

The first log shows 3rd and 4th gear pulls and going into limp.
The second log shows various pulls but not going into limp.

MAP readings seem high to me, indicating 23psi just before limp, and 22psi on the other pulls, so it looks like 23psi is the trigger for limp mode. I understand boost shouldn't really be over 17psi or so, so its definitely over boosting. (Its definitely a standard car, its not remapped).

Also, on the cold / limp log it seems like the MAP flatlines before going into limp at approx 3000rpm. You can clearly see the drop in rail pressure before it goes into limp which I'm sure is the ECU trying to pull it back before shutting it down.

On the hot / non-limp run there is a consistent spike in VNT request and MAP at about 2800rpm which then tails off, so I think when warm it can just about pull the boost back enough to prevent it from going into limp.

Fuel rail pressure seems to be as expected, as do MAP readings.

So I'm thinking that its a VNT issue, but I need to test the Turbo Control Solenoid (VNT Regulator). Does anyone have any other ideas? It looks to me like the turbo is going to have to come off for a strip and clean, eugh. :omg_smile:

Thanks for this long post!
I was following several discussions here with similar problem: too much smoke and limp mode sometimes.
Changed blown intercooler, TCV and MAF sensor. Got better but still smoky. Until I reached this last thread. So I compared readings from old MAF and new one, they were off by 3 kg/h on idle. (new one 15kg/h, old idles at 12kg/h)
Changed back to the old one and smoke is gone, no more limp mode.
It turns out that there are several versions of MAF sensors on market, depending on ECM, etc.
Hope this helps someone.

___
XC70 2005, D5, 120kw

Does this sound like a turbo/overboost problem?
 

Morning all,

My trusty S60 which has never had any occurrences of major engine warning messages in the last 80k miles ive had it (its a 2006 D5 euro 4 / 185) diesel recently proved me wrong, and has popped a red triangle and 'engine service urgent' message and running in limp home mode since,, arghh,,..

Reading through this thread, and i see a mention of foot to floor, when engine not fully warmed up,, hmm yes thats exactly what i had done overtaking a car and then some seconds after the warning message came up, probably only 1/2 mile from when the car was started up from cold, had
also had the battery disconnected prior (no idea if thats relevant..). Its on
150k miles btw.

Since ive tried checking for fault codes with end ELM327 and a few different apps (which in the past have shown they can detect fault codes and report when theres an issue) but all of these show no MIL on and no fault codes stored or impending, despite the red warning triangle & message (the engine one and a anti skid service one which comes and goes historically), so im wondering if its VNT related, have tried a few startup/warm up cycles and boost initially low, (previously when working fine was seeing 20psi typ) but now only up to 8psi at a push and running on reduced power.

Thoughts anyone, would be really useful to know what vida would report as to the source of these troubles.. anyone in the kent/sussex area ?